69 hp 383 eng info/help needed

[Steve Garner]

By way of intro, not a novice to restos and engine work by any means (next year marks my 40th year as a journeyman mechanic), but this is my first Mopar resto. Very much an OE guy and this is the direction this car will go. Very complete, very original, know the history from new, 69 Superbee.
This will be a very close to completely stock engine, externally totally. I am just getting started with the engine work and when I look for pistons what I seem to come up with is flat top pistons that would appear to leave a compression ratio of under 9 (think I calculated 8.8 on one calculator). Maybe my data is off (chamber size, deck height), but I don't think so. Maybe someone can confirm those nominal dimensions.

I feel like compression in that range leaves something to be desired. On my 442 I have oe compression of 10.5 and I do have to back the timing off some for pump gas, but it is very tolerable. In this instance, I would like to get at least 9.5, and preferably between 9.5 and 10.
The block will have to have a slight decking as it has to be sleeved on a couple of cyls, but that will be minimal and I want to keep it that way. What pistons and where to get them to accomplish this.

Also, what would be the ideal camshaft replacement, keeping in mind the stock heads and hyd lifters, that would equal or better the original performance.

Thanks
Steve

 

[CompSyn]

By way of intro, not a novice to restos and engine work by any means (next year marks my 40th year as a journeyman mechanic), but this is my first Mopar resto. Very much an OE guy and this is the direction this car will go. Very complete, very original, know the history from new, 69 Superbee.
This will be a very close to completely stock engine, externally totally. I am just getting started with the engine work and when I look for pistons what I seem to come up with is flat top pistons that would appear to leave a compression ratio of under 9 (think I calculated 8.8 on one calculator). Maybe my data is off (chamber size, deck height), but I don't think so. Maybe someone can confirm those nominal dimensions.

I feel like compression in that range leaves something to be desired. On my 442 I have oe compression of 10.5 and I do have to back the timing off some for pump gas, but it is very tolerable. In this instance, I would like to get at least 9.5, and preferably between 9.5 and 10.

The block will have to have a slight decking as it has to be sleeved on a couple of cyls, but that will be minimal and I want to keep it that way. What pistons and where to get them to accomplish this.

Also, what would be the ideal camshaft replacement, keeping in mind the stock heads and hyd lifters, that would equal or better the original performance.

Thanks
Steve

Yep, Chrysler's 10:1 factory rating on the 383HP was a bit optimistic, more like 9.2:1...

The currently available shelf pistons aren’t very accurate as you’ve discovered. With my 383 Road Runner, I’ll likely have some semi-custom pistons made that are copies of the originals.

I reason the stock 9.2:1 with 906 open chamber heads and today’s pump gas will be good enough for a street motor.

Cheers to keeping it a stock 383HP!!!

 

[oldbee]

+1 on above. Maybe 1-2 steps up from stock duration&lift from stock cam.

 

[CompSyn]

+1 on above. Maybe 1-2 steps up from stock duration&lift from stock cam.

For the camshaft, if he's keeping it mostly stock and with HP exhaust manifolds, I strongly urge him/anyone to call Bob Karakashian...

 

[beanhead]

This is an older article but maybe it will help you get some ideas? In the second one they add some performance stuff which it sounds like you're not going to do but it's an interesting read nonetheless..
http://www.hotrod.com/articles/mopp-0208-chrysler-383-engine-buildup-from-the-bottom-up/amp/

http://www.hotrod.com/articles/mopp-0209-383-engine-restore/amp/

 

[lewtot184]

last summer i built a 383 for a friends '69 super bee. used '906 heads with speed pro 2315 pistons. cam was a summit 6400. he seems to be very pleased with it.