Help with 383 Build

[joewithaboat]

Re: Help with 383 Build

If you call comp cams I would bet money they would tell you you are going to give up 10 or 15 ft pounds of peak torque to gain 15 or 20 hp if the only thing you change is the cam from the 264 to the 270.

An educated guess... peak torque prob in the 3,800 rpm area, give or take... and peak hp in the 5,000rpm area.

If you dont ever run the boat at WOT it may be best to go with the 264.

I would call them and ask. They love to chat about their cams. I bet they will tell you that most of the time a customer when selecting a cam from the catalog should pick what they think they need, then select the next smaller. This might be a perfect example of that.

They will no doubt want to know everything... Intake, carb, heads, exhaust, c/r, rocker ratio etc.

I also bet they will recommend a little more cylinder pressure... bump the C/R to 9.25 or 9.5

Let us know what they say.

 

[John_S]

Re: Help with 383 Build

I am assuming you are running a 15.5" diameter prop. On your type of boat, pitch selection is based on ability to get on plane (have good bite) and decent cruise efficiency. I also assume you already have tabs to help get on plane. Trying to run wot for any significant time will quickly drain those 70 gal tanks, and we are talking about only a couple of mph slower at wot. IMHO, if you focus your cam toward wot/higher rpm performance, that will not be what you want. I do not advocate the 270 for your application. I'd drop back to the 260. If it was a much lighter bow rider or similiar, I'd agree with the 270, but would also like to see a rpm intake.

When you discuss cams with them, make sure they know the type of boat and the your typical running weight (boat, fuel, water, people, gear, etc).

 

[pennyduke]

Re: Help with 383 Build

I'm pretty slammed here at work but I will try to call and report back. I would love it if they told me to go with 9.5:1 CR. Then I wouldn't have to change the pistons and rebalance. Right now my prop is a 16X14. The boat is a complete dog with the stock 5.0L engine in it now. Loaded down my top speed is 26mph(GPS) at 4000 rpm. It won't plane unless I move everyone forward. I often go from Virginia to Maryland to pick up relatives and would like to have alot more top end to get there quicker. I really appreciate all the help from everyone. Mike

 

[Scott Danforth]

Re: Help with 383 Build

for what its worth, my stock '88 275 hp 5.7 liter had 9.4:1 CR and ran on 87 octane with open chamber heads. the Vortec heads are less prone to detonation due to the combustion design and can tolerate higher CR's.

 

[pennyduke]

Re: Help with 383 Build

for what its worth, my stock '88 275 hp 5.7 liter had 9.4:1 CR and ran on 87 octane with open chamber heads. the Vortec heads are less prone to detonation due to the combustion design and can tolerate higher CR's.

This is starting to sound good. I really don't want to change the pistons. I have no problem runnng High Octane gas if I have to.

 

[Tail_Gunner]

Re: Help with 383 Build

I did read about all this for about a year before I started. There was a thread where Don s talked about 2 bolt verses 4 bolt. I don't know if he mentioned the 383 motor but I don't remember him having a problem with the 2 bolt. My origional plan was to order the stroker block from summit already bored and clearanced but they are out of stock.

Try to PM Bondo and ask him...Trust me here few have his experience...or Don...Don is a very straight forward guy...sometimes he might nip you a bit..doesnt bite though

 

[John_S]

Re: Help with 383 Build

I'm pretty slammed here at work but I will try to call and report back. I would love it if they told me to go with 9.5:1 CR. Then I wouldn't have to change the pistons and rebalance. Right now my prop is a 16X14. The boat is a complete dog with the stock 5.0L engine in it now. Loaded down my top speed is 26mph(GPS) at 4000 rpm. It won't plane unless I move everyone forward. I often go from Virginia to Maryland to pick up relatives and would like to have alot more top end to get there quicker. I really appreciate all the help from everyone. Mike

I am not that familiar with your model, but believe wot top speed should be more around 35mph and be able to cruise at 25. Check boattest.com, I think there were some Bayliner 245 data there. I haven't been on Bayliner's Owner forum in a number of years. There was allot of good data on the cruiser's there. I think they hit a wall at 40mph, regardless of what power you threw at them.

 

[pennyduke]

Re: Help with 383 Build

I owned a 1994 2452 about 8 years ago and it would do about 37mph. It had a Brand New Jasper 350 in it with a Bravo out drive. I should have never sold it. Oh well... I will call Comp tomorrow.

 

[pennyduke]

Re: Help with 383 Build

If you call comp cams I would bet money they would tell you you are going to give up 10 or 15 ft pounds of peak torque to gain 15 or 20 hp if the only thing you change is the cam from the 264 to the 270.

An educated guess... peak torque prob in the 3,800 rpm area, give or take... and peak hp in the 5,000rpm area.

If you dont ever run the boat at WOT it may be best to go with the 264.

I would call them and ask. They love to chat about their cams. I bet they will tell you that most of the time a customer when selecting a cam from the catalog should pick what they think they need, then select the next smaller. This might be a perfect example of that.

They will no doubt want to know everything... Intake, carb, heads, exhaust, c/r, rocker ratio etc.

I also bet they will recommend a little more cylinder pressure... bump the C/R to 9.25 or 9.5

Let us know what they say.

Comp Cams said to go with the 270. They really didn't ask me too many questions about Intake and exhaust. He said I should not have any problems with reversion. He also said that the 270 I was looking at was for a roller block and I needed the retro fit number. The link is posted below.

http://www.compcams.com/Company/CC/cam-specs/Details.aspx?csid=169&sb=2

 

[greg82255]

Re: Help with 383 Build

Yup, it's a great cam. You want part # 12-417-8. That's the retro-fit. The OEM roller is 08-417-8.

 

[joewithaboat]

Re: Help with 383 Build

Comp Cams said to go with the 270. They really didn't ask me too many questions about Intake and exhaust. He said I should not have any problems with reversion. He also said that the 270 I was looking at was for a roller block and I needed the retro fit number. The link is posted below.

http://www.compcams.com/Company/CC/cam-specs/Details.aspx?csid=169&sb=2

Don't forget you prob need to have heads machined for guide to retainer clearance.

Like Greg you will end up with quite a screamer.

 

[pennyduke]

Re: Help with 383 Build

Don't forget you prob need to have heads machined for guide to retainer clearance.

Like Greg you will end up with quite a screamer.

The springs and retainers I used are supposed to work with this cam without any machine work. I'm sure the machine shop will check that for me once I give him the cam and lifter set. If you would like to check it on paper, I posted the part numbers in this post. thanks

 

[Tail_Gunner]

Re: Help with 383 Build

The springs and retainers I used are supposed to work with this cam without any machine work. I'm sure the machine shop will check that for me once I give him the cam and lifter set. If you would like to check it on paper, I posted the part numbers in this post. thanks

LS6 spring's and Comp Cams retainer number 787

http://www.pacificp.com/forum/viewt...&start=0&sid=72a2f10f8cac040856d21288c9eebedd

http://www.compcams.com/Products/CC-'Pushrods'-0.aspx

http://www.pontiacstreetperformance.com/psp/valvetraingeom.html

 

[pennyduke]

Re: Help with 383 Build

I would like to know what everyone thinks about these lifters. I can save about $150 if I use them. I do not want to buy something cheep and have problems in the future. I just like to shop around for lower prices and saw these on Ebay.

http://www.ebay.com/itm/LUNATI-SBC-...Parts_Accessories&hash=item5ae6099d0d&vxp=mtr

 

[joewithaboat]

Re: Help with 383 Build

Lunati stuff has had a good reputation over the years, I however know nothing specific about those litters. If it were me I would probably go with comp just incase you have issues with something they will be more inclined to stand behind a product if you don't mix n match. I have also heard of fake/copy stuff on eBay, although that vender seems to have a pretty solid rating.

 

[pennyduke]

Re: Help with 383 Build

My Scat Assembly will be here tomorrow according to UPS. I'm excited. Now I'm shopping for the cam and lifter set. I think I will stick with the comp set from Summit.

 

[Maddoxsdaddy]

Re: Help with 383 Build

Did you go with the stuf i used? There was no machining needed other than the valve job. Springs/retainers went right on without additional modification. I've been verry happy with my motor build thus far. I'm able to turn a 21P stainless prop now at 4800 rpm and hit 58 on the speedo and still had throttle left to give her... I also used the 264 cam with stock vortec rockers.

 

[pennyduke]

Re: Help with 383 Build

Did you go with the stuf i used? There was no machining needed other than the valve job. Springs/retainers went right on without additional modification. I've been verry happy with my motor build thus far. I'm able to turn a 21P stainless prop now at 4800 rpm and hit 58 on the speedo and still had throttle left to give her... I also used the 264 cam with stock vortec rockers.

Yes I did use the same springs, retainers and keepers. The heads are done. I'm going 1 step up from the Cam you went with (270). But the springs should still work. I'm using the same Cam Greg used in his 383 Stroker build. The Scat Assembly just arrived, Headed to the machine shop in a few. Thanks for the help with the springs.

 

[Maddoxsdaddy]

Re: Help with 383 Build

You're welcome. Can't wait to see/hear the end results!

 

[pennyduke]

Re: Help with 383 Build

You're welcome. Can't wait to see/hear the end results!

Update... The bottom end is almost finished. I need some advice on an Oil Pump and head Gaskets. The machine shop said that all cylinders may not work out to exactly zero deck height but would be very close. I'm also going to have them install the heads and measure the pushrod length before I order them from Summit. Those roller lifters are very expensive. This may turn into a winter project if they don't speed it up. Thanks