Angle plug heads

[Yukonmuscle]

Can angle plug cylinder heads be used on a 350/383? Are there clearance issues? My vortec heads have small cracks in the cylinder head bolt holes and I have found a good deal in some dart pro 1 heads but they are angle plug, not straight plug. Is this gonna cause clearance issues? Holding the manifolds up to the vortec heads looks like angle plug heads would be fine but wondering if anyone has experience with this

 

[thumpar]

Re: Angle plug heads

The intake on non-vortec and vortec head equipped engines are different so you would need to change that also. You are also going backward in power.

 

[Yukonmuscle]

Re: Angle plug heads

I realize I will have the change my intake. Your crazy though if you think that vortec heads will make more power then darts pro 1 aluminum Cnc'd heads. Any idea if I'll be ok with the angle plugs?

 

[Bondo]

Re: Angle plug heads

I realize I will have the change my intake. Your crazy though if you think that vortec heads will make more power then darts pro 1 aluminum Cnc'd heads. Any idea if I'll be ok with the angle plugs?

Ayuh,.... IF ya could mount the exhaust manifolds, ya couldn't put the spark plugs in,...

Ya Need straight plug holes,...

 

[Yukonmuscle]

Re: Angle plug heads

Well that sucks! Such a good deal on these heads. I'm not gonna give up though..... Too stubborn and too good of a deal. I'm gonna go look at the heads and bring a manifold and some plugs with me just to make sure. You've never pointed me in the wrong direction yet bondo but I gotta see it to believe it....... Thanks for your input guys

 

[thumpar]

Re: Angle plug heads

I realize I will have the change my intake. Your crazy though if you think that vortec heads will make more power then darts pro 1 aluminum Cnc'd heads. Any idea if I'll be ok with the angle plugs?

You didn't mention that part in the first post.

 

[Yukonmuscle]

Re: Angle plug heads

Bought dart pro 1 angle plug heads for my 383 build and just so everyone knows the the spark plugs clear the factory merc manifold just fine. The plugs don't angle up at all just to the sides. There is plenty of room for the spark plugs and getting a boot on the plug is no problem either. Not sure if all angle plug heads are the same but the dart pro 1 heads definitely clear the manifolds with no issues at all. Thanks for everyone's input on the subject, I know I was told they don't fit but the deal was too good to pass up so I had to check for myself. Glad I did.

 

[Walt T]

Re: Angle plug heads

Those are very expensive heads and they're also pretty useless on an engine not built to utilize them. The plugs are angled to place the spark in the correct place in the chamber to take advantage of maximum quench and swirl effect which you will only get with the right pistons and camshaft. Just placing these on a Vortec engine I think will take you backwards. I'd sell them and find a good set of Vortecs.

You don't mention which Pro 1 heads you have, 180, 200, 215...etc. Then depending on the head CC (64 or 72) then the correct piston dish design is used along wit intake manifolds and camshafts. Dart is very very specific about head gasket thickness, head bolt torque, which manifold, and there may or may not be specifications as to how much cam lift is tolerated. You MUST check piston to valve clearances since you're using a Vortec cam with a system not intended for it. If it is a 64cc head set up, I would NOT use those heads without knowing exactly what your compression ratio is going to be. Engine self destruction is certainly a possibility.

My point is: Just because you take a part off a racing engine and bolt it on your basically stock engine doesn't mean you'll suddenly get massive power increase. An engine is a sum of its parts. You've gone through the expense for a custom 383 Vortec which is probably the best dang SBC stroker builds there are. Why mess with it?
I really believe you're better off selling those Darts and buying a good set of cast Vortecs, having them done, and then enjoying your good reliable stroker. Besides, cast is better than aluminum for marine use anyway.

I assume this is for your Crownline? I like those Sunrunners. That's a great stable hull and can handle some extra HP. So tell us about the 383 in it? We all are interested in these stroker motors.

 

[Scott Danforth]

Re: Angle plug heads

with the heads being aluminum. you may want to run a closed cooling system to stabilize block temps just to prevent premature head gasket failure.

If you run in salt water, you will need a closed cooling system to prevent corrosion

I doubt you will get anywhere near the RPM where the Dart heads will even be able to contribute. I would sell them as well, buy a new set of vortecs and pocket the difference.

 

[JustJason]

Re: Angle plug heads

When it comes to the automotive/racing stuff in general what you have to keep in mind is automotive exhaust manifolds/headers go down. Marine exhaust manifolds go up.

 

[Yukonmuscle]

Re: Angle plug heads

Wow easy Walt! Joking lol. I appreciate your concern but this isn't a stock vortec engine. Last year I pulled the 305 out of my boat, took a 98 350 vortec truck motor, freshened the bottom end and had the vortec heads fitted with comp keepers and retainers with gmpp springs for extra lift, comp xm270hr cam professional products crosswind air gap intake and a quadrajet carb from a merc 454 mag... This set up after re propping picked up 10mph over the stock 305 and put me to 59-61 mph on GPS. This set up worked well as at 61 mph I was still hitting the rev limiter a little but didn't want to go higher on the prop as I loved the power to plane fast and the hard mid range punch it had. The prop was a laser 2 25p that had been cupped, and re pitched to between 23-24 pitch

I wanted more....

My father has a 69mph seadoo that I want to beat in the top end.

This winter I I started assembling a 383. I already had a forged eagle crank, 5.7 scat rods and another roller 5.7 block laying around. The pistons I'm using are 18cc d dish Keith blacks. For valve train I'm re using the xm270hr cam but adding comp double roller timing set, comp magnum pushrods, comp roller tip 1.6 rockers comp roller lifters. Im also upgrading to a new edelbrock marine 750 carb and victor jr single plane intake with
Large ports to match the heads. The ignition is being upgraded to msd this winter as I'm sick of the 4950 rpm rev limit the merc system has. To effectively use the combination this year I'm realistically gonna have to push the max rpm up to 5500-6000 for maximum speed/power. As said the heads are dart pro 1s, they are 64cc, 200cc intake runners and they have the new heart shaped (vortec style) combustion chambers.

The block is prepped, hot tanked, Clearanced for the stroker crank, decked 010, and bored 030 and new cam bearings are installed. Last night I primed and painted the block (red to match the boat), tonight brass freeze plugs are going in. Next week I need to pull the 350 out of my boat to get the cam, timing cover, oil pan and flywheel out as I am reusing these things on the stroker.
Once the flywheel is in my hands the rotating assembly is going to the machine shop for balancing, if all goes well I will be assembling this motor at the end of March. Once the bottom
End is assembled I will remeasure how far the piston is in the hole at tdc and choose an appropriate head gasket to set quench to as close to 040 as I can get.

The last purchase I need to make is for exhaust. Even though I had no reversion issues with this cam last year I don't want to reuse the exhaust. With the larger valves, higher rpm I'll be using, and bigger flowing ports in the dart heads I think the factory manifolds will choke away too much air flow. Last year I made my own side exit exhaust tips and silencers and ran from the factory manifolds out the side. I need to upgrade the manifolds, but have not made a decision to what yet. Any suggestions?

Any more questions, please ask. I love discussing this stuff
Also just to let everyone know I'm not new to this stuff. I'm a licensed auto technician for last 12 years, I've owned a few small block hot rod cars, built a few motors for myself, friends and customers. Also for the last 3 years I've been in the marine industry doing fiberglass and gel coat repairs, boat restorations, performance mods..... There really isn't anything we don't do at my work other then canvas work

Also my boat is a 2010 bayliner 195 that I bought new...... Not your typical performance boat. And please let's not talk about how bayliner is a crappy boat. This is a family bowrider that me and my three kids spend every weekend using in the summer. Great boat whether I'm out with the kids cruising or out with the guys hammer down running the snot out of it. Boat was rock solid at 50mph in stock trim and same at 60mph with last years setup.
I don't know where the hulls limit is, I don't know whether it's gonna chine walk at 70+ or just stick at 65 and not go any faster no matter how much power I build. But I'm excited to find out

As always thanks for everyone's input and interest

Comments and questions always welcome

 

[Yukonmuscle]

Re: Angle plug heads

Scott. I believe with the setup I'm
Planning 5500rpm plus will be no issue to reach. See above post.

I only boat in fresh water, inland lakes so do not plan on adding closed cooling system. I can see the theory of closed cooling stabilizing coolant temps but I've never had an issue as of yet. My temp gauge shows 160F at all times after warm up. Even after a hard wot run they never climb above 165-170 and will run around at idle for an hr at 160. I'll keep an eye open on the temp gauge this spring during testing and tuning to see how it's going. If I need a closed cooling setup it's an easy addition to do..... Just more money, but at this point I can't not do it if it needs it.

 

[Scott Danforth]

Re: Angle plug heads

even fresh water atacks aluminum. I would still run a fresh water cooling system. with your mods your into a 5" x 22" heat exchanger core (same as big blocks). you will want to install the heat exchanger when the motor is fresh to avoid plugging the shell side of the heat exchanger with the sand and crap that ends up inside the motor with a sea water cooled motor.

not to mention your limiting RPM (5200 for the alpha) is usually not the motor, it is usually the drive in many cases. if you have an alpha, you need to watch your hole shots. the Alpha will blow up with your stroker motor if you do not ease into the hole shot. plenty of people putting high power into alphas. need to make sure you ease into the hole shot, run synthetic lube along with a drive shower to keep the gear box cool

for exhaust, I would jump straight to CMI headers myself. then again, I know the guys there in Appleton. If you were looking at a manifold, then I would look at EMI or Imco with a stainless riser. make sure you get the water passages coated, even in fresh water.

 

[Walt T]

Re: Angle plug heads

I'm sure we are all interested in the results so update us when its all working. I have no experience with the Bayliner hull at speed so we shall see. Bayliner quality is much improved from 20 years ago. They still tend to offer underpowered boats in the larger sizes but are better about allowing buyers to purchase larger engine packages such as in yours where the 4.3 and 5.0 were offered. I built a stroker for my 22 foot cuddy which is not a speed platform but hey its what I got. There are a few dangerous hulls out there like the Jolly Rogers but the Bayliner with a 5.0 is already pretty speedy and very stable. I think the strakes will keep it steady through 70, not really sure how much lift you'll get.

If you're gonna run above 5000 rpm frequently I'd consider the drive. Stock Merc drives aren't really designed for high rpms but I've pushed plenty of them past that. Volvos too.

Custom exhaust is pretty much your only option if you want to keep the same engine covers. Gil Marine makes some very nice tuned manifolds for wet systems. In my experience the exhaust really doesn't come into play until 5500+ rpms. It's a large diameter system and as the boat moves through the water there is a 'suctioning' effect on the exhaust exit as the drive moves through the water.
Utilizing a thru hull dry system with or without water injection brings it's own problems. The tuned systems do a very good job of cylinder evacuation which is all we really want and some back pressure is needed to accomplish that. It's a very delicate balance, and the yield between a perfectly tuned exhaust and a stock exhaust (like I have on my own stroker) isn't hardly noticeable at standard cruising. Top end is where all that comes into play. As I said, some back pressure is essential to get the scavenging effect and will also help with low end torque which you're gonna lose a bit of with your set up. My point is, don't worry too much about exhaust. 6000 rpm is loafing and most exhaust systems can handle it fine. You're already spending money where it will do the most good. I don't think I would use the 1.6 rockers but I also didn't check the cam specs, I'll look those up later today.

Careful with all the high rpm preps, that moves the entire powerband up in the rpm range. The higher rpms, the more HP, but that also moves peak torque up in the rpm range also. A small boat like yours it's probably fine, a heavy boat like mine I need it all down low in the rpm range. Otherwise it all sounds like a very good build. I still stick with my opinion that cast Vortec heads are better used here. The Darts are great for 6000+ but you really aren't gonna spend that much time at that speed. Sell em and use the cash for gas, guys like me and you need a lotta gas. It's major fun goosing those 383's, or 389 in my case.

 

[JustJason]

Re: Angle plug heads

Your trying to get a bayliner 195 to hit 70???

 

[MikDee]

Re: Angle plug heads

Your trying to get a bayliner 195 to hit 70???

If it stays together, I guess he'll find out the speed limit of that hull? By the way, what kind of fuel do you need to run with that highly modified engine?

 

[Scott Danforth]

Re: Angle plug heads

If it stays together, I guess he'll find out the speed limit of that hull? By the way, what kind of fuel do you need to run with that highly modified engine?

if the compression ratio stays under 10, 89 octane. if its over 10, 91 octane.

 

[Yukonmuscle]

Re: Angle plug heads

Yes I'm def trying to get my bayliner 195 to hit 70 or more! Compression is gonna be around 9.5.1, be nice to run regular but we will see. The boat is towed to the lakes every weekend so I can fill up with any fuel I need and don't need to run what the local marina sells. I think it will do 70 plus but we will find out. When using the prop I have now, using actual speed and and rpm I can correctly calculate slip with a prop calculator. So just by raising my rpm from 4900 to 6000 should put me close to 70. I'm expecting to have to run a 25 pitch prop this year, with the extra power the 24 I have now might not be big enough..... We will see what happens this spring I guess. I can't find any other bayliners online that are running 70+ mph so it's tough to ask questions about the hull to anyone that's experienced

 

[thumpar]

Re: Angle plug heads

Yes I'm def trying to get my bayliner 195 to hit 70 or more! Compression is gonna be around 9.5.1, be nice to run regular but we will see. The boat is towed to the lakes every weekend so I can fill up with any fuel I need and don't need to run what the local marina sells. I think it will do 70 plus but we will find out. When using the prop I have now, using actual speed and and rpm I can correctly calculate slip with a prop calculator. So just by raising my rpm from 4900 to 6000 should put me close to 70. I'm expecting to have to run a 25 pitch prop this year, with the extra power the 24 I have now might not be big enough..... We will see what happens this spring I guess. I can't find any other bayliners online that are running 70+ mph so it's tough to ask questions about the hull to anyone that's experienced

There is a reason for that.

 

[Yukonmuscle]

Re: Angle plug heads

Doesn't mean it won't do it or can't do it safely. This boat is the perfect sleeper other than the side exit exhaust.