Building a 383 Stroker

[joewithaboat]

Re: Building a 383 Stroker

I'll definitely loook into MKos1980's post. I'll see if I can find him and see the specs of the motor he is running. Looks like I'll skip the port work on the heads. As for the cam, I want to get a retro-fit roller but we'll see what the budget allows after I buy everything else. I'll take a look at those cams - maybe I'll even give Comp Cams or Crane a call and see what they recommend for a ~375 hp 383.

Joe, that article was really interesting. I'm surprised a stingray maxim hull could handle 100 mph without falling apart. I did notice a few things in that article that looked like they may help my build.

1. Is it true that a water crossover system instead of a circulation pump will increase power and keep the engine cooler? I asked a friend who works on "go fast" boats he says the best thing about them to him is less stuff in the way to work on them and one less thing to fail. I know from being in a dyno room & from many years of drag racing that it takes around 5 hp to run the pump. I have heard others question the cooling (helping or hindering) I would run one with a t-stat if you choose to do it.
2. They installed a bravo coupler and mated it to an alpha drive. Are the shaft/splines the same, and would it make sense to get a bravo coupler for 375 hp? I dont know, but i dont think you need it. Remember they were using over 600lb of torque.
3. Exhaust. Seems like I need a good one. Those CMI headers look so cool... but are they worth the 2grand... At very least, I'll switch out the iron manifolds for some aluminum ones to get rid of some weight in the back. Anyone ever used these tail pipes? they claim to add 10hp. (http://www.cpperformance.com/p-1341...ce-mercury-manifolds-standard-dimensions.aspx) Aside from a good engine exhaust is very important, the good stuff is $$$ look on ebay but be carefull buying used!
4. I think the aluminum intake/exhaust, and crossover should remove about 80 or so pounds from the back of the boat. Will this make any noticeable difference?

Prob hard to tell in the seat of your pants, but any weight savings will add up in the end.

 

[greg82255]

Re: Building a 383 Stroker

I've done some research and apparently the splines/shaft on the bravo coupler are the same, so it would probably work, but I'll do some more research and see if it's really necessary (really doubt it is). As for the crossover vs the circulation pump, I'll probably buy a crossover. They look cool in addition to saving some HP. The only thing I'd be worried about is that the Alpha impeller will be responsible for pushing water through the entire motor..

I'm not having much luck with exhaust on ebay. I've tried looking for CMI, Stainless Marine, IMCO and a few others without much luck. I'll keep looking over the winter.

 

[greg82255]

Re: Building a 383 Stroker

So I spoke to the machinist again today. I'm going to by a set of used vortec heads from him, and he said that he still recommends the performer intake over the performer rpm air gap because the performer operating range is idle-5500 RPM whereas the RPM is 2300-6500. He said I want the engine making power right out of the hole and that there isn't need for power above 5500. He does make a good point. Anyways, I'm going to buy the heads from him so at least I can get those going. Any thoughts on what he said about the intake?

 

[joewithaboat]

Re: Building a 383 Stroker

So I spoke to the machinist again today. I'm going to by a set of used vortec heads from him, and he said that he still recommends the performer intake over the performer rpm air gap because the performer operating range is idle-5500 RPM whereas the RPM is 2300-6500. He said I want the engine making power right out of the hole and that there isn't need for power above 5500. He does make a good point. Anyways, I'm going to buy the heads from him so at least I can get those going. Any thoughts on what he said about the intake?

Look here

http://www.popularhotrodding.com/te...gap_performer_intake_manifold_tech/index.html

I have never used the air gap personally. I have used both performer and performer rpm on both small block fords and small block chevy's. With the power level you are shooting for you will gain a little hp up top and give a little TQ down low, RPM vs regular performer. Vortec heads make a lot of TQ so .... you can aford to loose some down low, your alpha will think so too.

If you choose to not buy that intake from your machinest i would put off telling him until later. I find that people that are trying to sell you parts are sometimes get an attitude when you dont want to buy what they are selling. You don't want him to have an attitude untill he is done with your machine work.

Based on my having used both on a small block chevy, I would use the RPM. Im sure if you called Edelbrock and told them you were building a 375Hp vortec headed 383 to operate in a boat at 5,000rpm they will tell you the same. You could also ask the cam manufacturer as you are selecting a cam.
my .02

 

[joewithaboat]

Re: Building a 383 Stroker

I've done some research and apparently the splines/shaft on the bravo coupler are the same, so it would probably work, but I'll do some more research and see if it's really necessary (really doubt it is). As for the crossover vs the circulation pump, I'll probably buy a crossover. They look cool in addition to saving some HP. The only thing I'd be worried about is that the Alpha impeller will be responsible for pushing water through the entire motor..

I'm not having much luck with exhaust on ebay. I've tried looking for CMI, Stainless Marine, IMCO and a few others without much luck. I'll keep looking over the winter.

Again i dont think the coupler is going to e an issue for you as long as yours is in good shape

on Ebay motors try " marine exhaust"

If your current exhaust is in less than perfect condition and you are going to buy new, i would at least get some type of enty level performance and not spend money on "stock" stuff.
If current is ok, you can always upgrade it later.

 

[Failproof]

Re: Building a 383 Stroker

Having built and ran multiple 383 combos, one of the most well rounded and mannered ones used edelbrock performer alum heads, and the performer rpm intake, with a 750 holley. You will have plenty of torque up untill the 2000 rpm when the manifold starts to flow. You want a nice linear torque curve to carry you to the 5000 rpm lmit, not one that starts to fall right where the motor will be used the most. If it was in a vehicle then gobs of torque at off idle works well, as you are cruising at 2500 rpm, and have multiple gear sets to keep you in the meat of the motor. I have seen multiple alpha 1 drives damaged by dropping the hammer out of the hole, and trying to harness 400 ft/lbs right off the bat. You are going to have to ease into it, increase the rpm's then throttle down to limit outdrive issues.

 

[greg82255]

Re: Building a 383 Stroker

So it seems like the consensus is that the performer RPM will work better than the performer. The machinist isn't actually making $ off the parts he is selling me (they belong to someone else and have been sitting in his shop for ~4 years), so I don't think he will care if I only buy the heads. I'm going to call him in a few minutes and talk about it. Has anyone used the RPM Air Gap? I'm actually not even sure if the air gap would fit inside my engine compartment b/c the flame arrestor was already close to the hatch.

My exhaust manifolds are pretty much brand new. I bought them in April from West Marine (thank god for price matching) and they have one season of use (40ish hours) on them. That's why I thought about selling my 3-inch risers and buying just the tail pipe above that supposedly gives a 10+horsepower gain when bolted on the stock manifolds. I'll keep searching ebay and see what I find.

 

[John_S]

Re: Building a 383 Stroker

The difference in height between the Performer and Performer RPM is less than 3/4".

RPM vs Air Gap, Negligble performance difference. Going to vortec heads which do not have exhaust crossover, significantly reduces the intake manifold temps. With just oil splash from the oil galley, and conduction through water and block, intake will not be hot. That heat is not a bad thing for driveability. RPM gets my vote.

 

[joewithaboat]

Re: Building a 383 Stroker

I love the RPM that i currently have (not on a boat). I as i said have never had an Air Gap, but the above article is interesting. esp. the drop in runner temp after WOT.

 

[wca_tim]

Re: Building a 383 Stroker

I'll talk about the engine that's in my little boat since that's what is most applicable to your toy.

I'm running an airgap rpm and it makes great power - never any issues with low end torque. The difference in height between it and the torker 2 I started with required shimming the engine hatch up about 3/4 of an inch, but that and the AFR195 heads made a substantial difference in power over the torker and lightly ported world products sportsman 2s - even with a bit of drop in compression so I could add a blower (was thinking probably procharger or vortech blowthrough). btw. I would throw the stock flame arrestor away. it's a lot more restrictive than it looks and worth some real horsepower... I had to jet a little richer and gained a couple mph once I got rid of it.

I would run a tbolt 4 ignition (and I am right now). they're inexpensive and in my experience so far as close to bulletproof as it gets. I saw little or no difference oin performance between the stock ignition a crane cd ignition (Hi-6m). The stock v-8 module(s) will be fine. You won't have enough cam overlap to worry about needing more advance at idle. If I were you, I would start there with the ignition, optimize total timing for max peak horsepower / wot and assume it'll be just fine everywhere else. Start out around 28 degrees total timing and bump it up 2 degrees at a time until it either detonates or it doesn't pick up any more top end. then back off 2 degrees... Get the jetting close to right first.

Exhaust is a tough nut. I got lucky and picked up a set of unused polished imco powerflows for 600 from a guy off craigslist and a couple months later found a pair of long imco risers on ebay for under 200. (lucky). There are a couple of sites that have swap boards where you'll see small block exhausts once in a while (big block all the time... most people building marine engines go for cubes first). I'm not sure what else I would have gone with if I had to go new. The engine builder was clear that the powerflows make more power on his dyno than any other marine exhaust aside from true long tube headers (bigger dollars).

After cubic inches, good heads are the next best place to put your money imho... good heads and a realtively mild cam will make great power and idle just fine.

I agree with the comp xm cams for good performance out of a marine small block on a stock, fairly conservative cam grind. Comp will tell you to run an xm-270H with 1.6:1 rocker arms. if you go roller, then the 276H...

I would definitely go closed cooling from the start if you are going to run aluminum heads, intake, etc... especially if you're going to ever think about running in salt water or even brackish. I bought a heat exchanger and thermostat housing for a big block and added some hoses to make it work on my engine. I spend under 400 for the whole set-up and the heat exchanger was unused. ;-)

I started with block zero-decked and a tight (ca 0.04") quench, -12 cc dished forged pistons with 46cc combustion chambers for about 10:1 compression with the original iron sportsman heads on 93 octane and never had any issues with detonation.

I'll read through some more and try to follow along as you make progress. Lots of really knowledgeable guys on here. Mkos, john, bond-o, and some of the others know their stuff and have been telling it to you straight. Have fun with it!

I would run your original coupler. I'm still running the one that came with the v-6 that was in the boat when I bought it. I would also not consider running a crossover without adding a bravo style raw water pump. alpha impellers come apart, you don't want to lose circulation all together if the impeller craps out...

btw. My experience may not all be representative. If I'm honest about how much I spent, it's a lot more than you're talking about. I'm betting I spent as much on the bottom end / short block as you are planning to spend on your whole engine. anyhow, hope this is helpful. just my experience

 

[greg82255]

Re: Building a 383 Stroker

I'll talk about the engine that's in my little boat since that's what is most applicable to your toy.

I'm running an airgap rpm and it makes great power - never any issues with low end torque. The difference in height between it and the torker 2 I started with required shimming the engine hatch up about 3/4 of an inch, but that and the AFR195 heads made a substantial difference in power over the torker and lightly ported world products sportsman 2s - even with a bit of drop in compression so I could add a blower (was thinking probably procharger or vortech blowthrough). btw. I would throw the stock flame arrestor away. it's a lot more restrictive than it looks and worth some real horsepower... I had to jet a little richer and gained a couple mph once I got rid of it.

I would run a tbolt 4 ignition (and I am right now). they're inexpensive and in my experience so far as close to bulletproof as it gets. I saw little or no difference oin performance between the stock ignition a crane cd ignition (Hi-6m). The stock v-8 module(s) will be fine. You won't have enough cam overlap to worry about needing more advance at idle. If I were you, I would start there with the ignition, optimize total timing for max peak horsepower / wot and assume it'll be just fine everywhere else. Start out around 28 degrees total timing and bump it up 2 degrees at a time until it either detonates or it doesn't pick up any more top end. then back off 2 degrees... Get the jetting close to right first.

Exhaust is a tough nut. I got lucky and picked up a set of unused polished imco powerflows for 600 from a guy off craigslist and a couple months later found a pair of long imco risers on ebay for under 200. (lucky). There are a couple of sites that have swap boards where you'll see small block exhausts once in a while (big block all the time... most people building marine engines go for cubes first). I'm not sure what else I would have gone with if I had to go new. The engine builder was clear that the powerflows make more power on his dyno than any other marine exhaust aside from true long tube headers (bigger dollars).

After cubic inches, good heads are the next best place to put your money imho... good heads and a realtively mild cam will make great power and idle just fine.

I agree with the comp xm cams for good performance out of a marine small block on a stock, fairly conservative cam grind. Comp will tell you to run an xm-270H with 1.6:1 rocker arms. if you go roller, then the 276H...

I would definitely go closed cooling from the start if you are going to run aluminum heads, intake, etc... especially if you're going to ever think about running in salt water or even brackish. I bought a heat exchanger and thermostat housing for a big block and added some hoses to make it work on my engine. I spend under 400 for the whole set-up and the heat exchanger was unused. ;-)

I started with block zero-decked and a tight (ca 0.04") quench, -12 cc dished forged pistons with 46cc combustion chambers for about 10:1 compression with the original iron sportsman heads on 93 octane and never had any issues with detonation.

I'll read through some more and try to follow along as you make progress. Lots of really knowledgeable guys on here. Mkos, john, bond-o, and some of the others know their stuff and have been telling it to you straight. Have fun with it!

I would run your original coupler. I'm still running the one that came with the v-6 that was in the boat when I bought it. I would also not consider running a crossover without adding a bravo style raw water pump. alpha impellers come apart, you don't want to lose circulation all together if the impeller craps out...

btw. My experience may not all be representative. If I'm honest about how much I spent, it's a lot more than you're talking about. I'm betting I spent as much on the bottom end / short block as you are planning to spend on your whole engine. anyhow, hope this is helpful. just my experience

Tim, thanks for your reply. I was hoping you would find this thread and post. I'd have to agree that I am on a tighter budget. I am using a Scat cast steel crank, hypereutectic pistons (-18cc dish), forged I-beam rods with ARP bolts, and a set of iron vortec heads, I believe the chambers are 62cc so compression is somewhere around 9:1. About 3 grand for the machining and parts for the long block, and I'm assembling everything myself.

Haven't decided on a cam, rockers and springs, although I am leaning toward the roller cam. I'll look into both of the part #s you suggested. I actually replaced my stock T4 ignition this year with a Delco Voyager system. The T4 kept giving me problems and the amplifier eventually just died. I'd like to stick with the Delco Voyager for now, as it is brand new and I just spent $300 on it. I'll also be buying a new carb (probably a holley) because I don't want to reuse the Q-jet.

I suppose that finding a good used exhaust system always involves some luck. I love the look of those polished E-top CMI headers and I may eventually just give in and buy them, but for now I'll probably use my stock manifolds with some kind of modified risers (plenty of sets of stainless risers on ebay) unless I come across the deal of a lifetime.

I'm really stuck on the intake now. My machinist again told me that he highly recommends the performer over the RPM. He says the air gap won't do much in a boat because there isn't much ventilation in the bilge so air will not move through the intake to cool the air flowing through the passages. Everyone here seems to suggest the RPM or the RPM air gap. Luckily I have some time to do some more research before the intake goes on.

If I remove the circulation pump to gain some power and then add a bravo raw water pump, my net gain will be 0. Remove one pump from the belts, add another. Maybe I'll just keep whats there. But aren't alpha and bravo impellers basically the same except for on the alpha its in the drive? And if the alpha impeller craps out, don't I lose water flow and overheat anyways? Same with the bravo impeller? I saw a post by bomar76 who has a 460 hp 385 stroker and doesn't use a circ pump and has an alpha drive, so that's what got me thinking on the crossover. Hopefully he will find this thread and post too. Also, he uses an air gap intake...

 

[John_S]

Re: Building a 383 Stroker

I run the EdelB vortec performer on my stock 350 vortec. The main reason I choose it was I was going with a q-jet at the time, and thought it was a better match for my app. Since then, I have switched to squarebore, and wish that I went with a RPM from the start. I run an alum 1" 4-hole spacer on it now. Might have picked up a few hp with that.

With the HP you are going for, along with your future plans on exhaust, the rpm or rpm air gap, is the right choice. Look at the step 3 of that HT383 build article I posted earlier in the thread.

 

[greg82255]

Re: Building a 383 Stroker

I run the EdelB vortec performer on my stock 350 vortec. The main reason I choose it was I was going with a q-jet at the time, and thought it was a better match for my app. Since then, I have switched to squarebore, and wish that I went with a RPM from the start. I run an alum 1" 4-hole spacer on it now. Might have picked up a few hp with that.

With the HP you are going for, along with your future plans on exhaust, the rpm or rpm air gap, is the right choice. Look at the step 3 of that HT383 build article I posted earlier in the thread.

I doubt I have room for a spacer, as I am already close to hitting the engine hatch. Hopefully I have room for the .7 inches of extra height on the RPM or Air Gap, and the height of a new flame arrestor. I probably should have measured that when I had the engine in the boat... oops.

I'm getting more intrigued by this idea of a crossover. My machinist said he has never used one but has heard of people doing it, and to research it before I decide which way to go. I'm hoping bomar76 will chime in about how it works for him, but it looks like he hasn't logged onto iboats since August. If anyone else is using a crossover, please jump in and let me know how its working.

The machinist says that everything (block, heads, balanced rotating assembly) should be ready by the end of next week. Once I get it back, I'll start a new thread with pictures and part #s and be looking for suggestions along the way. If I can find my video camera maybe I'll even shoot a movie or 2.

 

[joewithaboat]

Re: Building a 383 Stroker

Make sure to buy a book (HP Books has several) on "small block chevy" engine assembly. It will save you tons of time/mistakes. Looking forward to your assembly post.
If its your first time poking pistons & rings, a bore specific (non adjustable) ring compressor is the best money you will spend.
http://www.summitracing.com/parts/SME-904030/

 

[greg82255]

Re: Building a 383 Stroker

It is my first time installing pistons. I was looking at one of the ring compressors that you tighten with a screwdriver. If it's better to use the non-adjustable, I'll get that instead. Going to make an order soon from summit (oil pump, gaskets, rear main seal, a few tools, etc).

 

[joewithaboat]

Re: Building a 383 Stroker

I have put pistons in prob 100 engines, half of which were with the old adjustable type. I cussed myself for being so cheap the first time i tried a fixed tappered type. They almost fall in!
Get some rod bolt boots as well, to protect the crank Journals. I would get a book before you start ordering parts. I would also suggest a bolt on oil pump pick up and steel sleeve oil pump drive. The "hp books" book will tell you all this stuff.
If you go with roller cam dont for get the dist drive gear, again all in those books....

 

[John_S]

Re: Building a 383 Stroker

I run stock exhaust manifolds with 3" center risors and the top of the K&N flame arrestor is just above the top of the elbows. That is as high as I can go, without shimming the doghouse or removing a layer of sound insulation. If I did change to a RPM, would remove the spacer, and have slightly more room.

 

[greg82255]

Re: Building a 383 Stroker

I have picked up and read through 2 books on rebuilding the sbc with pictures and performance recommendations. I have also watched 3 DVDs on rebuilding a 350 several times over. In addition to the parts I am ordering, I'm also getting some engine bags, assembly lube, rod bolt boots, thread sealer, thread locker, silicone sealer, balancer installer, crank socket, ring compressor and ring expander. Haven't picked a cam yet but I will make sure it has the right dist. drive gear and lobe for the mechanical fuel pump. I'm also ordering new head bolts, main cap bolts, oil pump/drive rod/pickup, Holley mechanical fuel pump, gaskets, oil pan studs, carb studs, timing cover bolts, and vortec intake bolts. Once I pick a cam I'll get a timing chain/sprocket. Ill also get valve covers later.

I think I have all my bases covered. If anyone sees that I'm forgetting something please let me know.

 

[joewithaboat]

Re: Building a 383 Stroker

I have picked up and read through 2 books on rebuilding the sbc with pictures and performance recommendations. I have also watched 3 DVDs on rebuilding a 350 several times over. In addition to the parts I am ordering, I'm also getting some engine bags, assembly lube, rod bolt boots, thread sealer, thread locker, silicone sealer, balancer installer, crank socket, ring compressor and ring expander. Haven't picked a cam yet but I will make sure it has the right dist. drive gear and lobe for the mechanical fuel pump. I'm also ordering new head bolts, main cap bolts, oil pump/drive rod/pickup, Holley mechanical fuel pump, gaskets, oil pan studs, carb studs, timing cover bolts, and vortec intake bolts. Once I pick a cam I'll get a timing chain/sprocket. Ill also get valve covers later.

I think I have all my bases covered. If anyone sees that I'm forgetting something please let me know.

Looks like your off to a great start! Take it easy on the thread locker. PST works great on head bolts. Enjoy...looking forward to your build thread.
oh...
If it means getting a better cam(roller) cause you have more money left, the original head, main, pan bolts etc are fine as long as they are not damaged. On the other hand i did the same thing on my first total new build. I studded everything i could....looked good to! Good times, brings back good memories!

 

[greg82255]

Re: Building a 383 Stroker

I was only planning on using the thread locker (and it's blue, not red) for the cam bolts and maybe the main cap bolts, flywheel/coupler bolts, and pulleys/bolt-on accessories. I've heard for the main caps it isn't necessary but mechanics use it for insurance. The ARP Thread Sealer is for the head bolts that go into water jackets. I'll coat the others with some engine oil before they go in.

The bolts only come out to $200 so they won't be a problem. I'd rather have the piece of mind that I have new bolts and studs. I'm 90% sure I'm going to buy the roller cam anyways.

My next big decision is deciding what color to paint the motor.. I really want the Mercury Racing Metallic Blue paint, but it's $26/can. Is there a close match to it out there? I don't want to do the Chevy orange, and I did the 305 in my last boat in red. Also sick of black.