I would like to take my stock rebuilt 383 and bump it up just a bit.

I already have a holly street dominator. I will be adding HP manifolds with flowmasters. And it already has a edelbrock carb that is running fine.

So I would like to bore it out .030 and add domed pistons and a cam.

What do you'all suggest?

The car has PS A/C and it has an automatic that I'm going to leave stock except for a shift kit.

I would like a lumpy idle but decent street manners and yet run it at the strip a couple times a year.

Got some 28" x 9" x 15" M/T slicks.

Also has a 4:10 SG that will be bringing up the rear.

So just want to bore it out add domed pistons and a lumpy cam.

Thanks guys

Put in a stroker crank. That is the best way to increase horsepower with out effecting street manners.

i have 70 challenger 383 10.5 comp. 509 purple shaft cam hooker headers holley 700 torker2 intake 3800 stall speed 28 x 9 x15 slicks 430 gears everything else is stock good luck with your build

12.67@110 in the quarter

If it's a recent rebuild then there may be no good reason to bore .030" unless a piston choice requires it. The overbore isn't worth the trouble for HP unless the bores are out of round now. Diamond makes off-the-shelf forged pistons that start at 4.28". But KB-Silvolite offers hyper pistons in std. bore that will work in a cylinder that has been honed .002-.003" over std. KB offers a flat top with valve releifs and a domed piston for more compression.

A domed piston is only necessary in a 383 if you need more than (about) 11:1 compression.

Your best investment may be in a set of closed chamber aftermarket heads such as the 440source or even better the Edelbrock RPM heads.

The closed chamber will give a smaller combustion chamber and net the higher compression you seek without a piston change. The heads will also result in more flow even with the stock cam and will really come alive with a mild cam upgrade.

The MP.484 lift hydraulic is a popular choice on many sites. But beware the lopey idle. Lopey idle comes from excessive overlap of the intake and exhaust valves. The more overlap, the greater the required stall speed of the converter for the cam to work. Lopey idles don't make more HP. You can get what you want without cam overkill and a converter change if you choose carefully.

Consult Hughes Engines for a cam change. I bet they have exactly what you need.

Read, I really mean study, the article "Resto to Rad". It'll help a whole lot.

See....Camshafts and converters go together. His .509" works well with a 3800 stall converter and 4:30's. That's not a "bump up a bit" for your 383. That's a huge leap. Respectfully.

Use caution on the cam choice. Even the factory used a higher stall converter when they used the "HP" cam in the 335 horse 383 and HiPo 440's. And that's a small camshaft by todays standards.

It is a 1967 383 so it has the closed chambered heads.

\I do not know the cc's of these at this time.

The Stealth head suggestion has merit; pump gas will limit your CR anyway. Might go with a better dual-plane intake. A good 2.5" exhaust. More lift, not more duration if you plan to use the A/C and have decent throttle response and street manners: something around 224/234 @ .050 with .500/.525 lift or so. Look at Engle's website. I would not run the MP 284/.484 cam unless you have a loose converter. CR, duration, and converter need to work together.

This was the mild 383 build I had in a Dart some years back. I switched to the RPM intake and ran a best of 12.31 @ 110. Ron

http://www.bigblockdart.com/ron_nies/ron_nies.htm

With 4.10's, Street Dominator intake, and the other stuff, you could run a healthy cam with a loose convertor, or a smaller cam w/ stock convertor.

If it were me, I'd think about one of those newer 9.5" convertors and pick the cam from the bottom part of the page.

The way I look at it, a person could take your basic chassis/gear/longblock, and either build a car that runs mid fourteens, or high twelves. The cam and convertor will be the biggest difference.

I know which way I'd go...

I'd also think hard about whether I really wanted to spend the money to switch over to stock HP exhaust manifolds, too. As opposed to a set of inexpensive headers, which would be a noticeable step up from them.

Also, might be worth a call to Dwayne Porter (aka Fast68Plymouth here on the board) to have him spec a cam EXACTLY for your combination. He's one of a number of guys who're real good at picking lobes to make that engine of yours fly. Especially if you really want to stick w/ iron manifolds.

Just my .02.

-Bill

You should have 516 close chamber heads so dome pistons are out. i would look for a good set of flat top pistons, deck the block bringing the pistons to zero, use 214/174 valves in the heads with some bowl blending and port match cr should end up somewhere around 9.5 to 1, keep the cam in the 218 to 226 max @.050 range. and you should have a nice setup able to run 13's

I would sell the 516 heads and use the money towards a set of 440source stealth of edelbrock rpm heads. Weight savings and better flow than stock. Add to that a cam, I hear the comp xe268h is a good cam for a street/strip 383, however I would probably take a it a 1/2 step more aggressive and go with the lunati voodoo 60303. Add a 3000rpm stall converter to either of the above. Also go with a set of headers. I installed a set of summit el cheapo headers and they needed a few spots dinged but nothing crazy. And they only cost a little over 100 bucks versus $$$ for factory hi-po manifolds.

Thanks guys.

The heads have been go thru and are working fine. so They will not be changed. If I understand it correctly the 516's cc about 78 is that correct. If so then domed pistons are out.

So a good set of flat tops and try to end up around 10.0 to 1 are in.

Next the HP manifolds I already have along with the flowmaster exhaust from front to back.

I was looking at the e268h comp cam, but on the installation notes it is saying you need to do head work, stock springs are out and you need adjustable valve train. So that would kinda kill the idea of not touching the heads. Although I'm not opposed to taking them apart and relieving an area for clearance issues. Adding better springs and adjustable rocker arms. But I was trying to stay away from doing that.

I also did not want to change the converter unless absolutely necessary.

Thanks for your help so far.

Would love to hear is someone knows the cc's for sure on 516 heads and e268h install stories.

Thnaks again

gary

Any kind of cam change without a converter change is really going to hurt low speed performance. Keep a very close eye on the intake closing point of any new cam you look at. four degrees or less added intake closing point will probably not hurt too much, start going beyond that and you had better get some more compression in it and a looser converter. Two items that stand out that will help you are a flat tappet cam and a stroker. The solid cam will allow a more agressive profile and still have a reasonable intake closing point due to the lash.
The stroker will give you the bottom end grunt to really work the stock converter and make it a whole new motor torque wise. Nobody need know about the stroke increase either!
If you start playing with numbers, you can come up with a 9.5 to one combo with flat top pistons, making sure piston to head is inside .035 to .040 . That will help wake up the motor. You have many options. A stroked stock 383 crank (3.54)can use a chev rod and rod bearing in a long rod of 6.7 or 6.8 length, giving you a piston compression height of 1.5 to 1.4. That would allow for a light piston, and really help things out. You would be at 406 cubes, .030 over.
These suggestions may or may not be inside of what you are willing to do, but thought I would throw them out there to give you some ideas.

Seems you want to change things as little as possible, so I thought I would throw out another scenario. If your current pistons and rings are in great shape, you can pull the heads, check the piston to head, have them cut if need be to max out compression, and adjust the piston to head clearance a bit if thicker than stock gaskets are in it now. Then add a good cam, tune it, and enjoy.

if you have stock valve springs your not going to get away with a big cam, maybe a stock RR cam and stock RR springs otherwise the heads will have to come apart and guides will have to be cut down for the higher lift cam, spring seats cut ect. ect.

IMO, staying with stock springs is a BAD idea. A 40 yo spring may not even be adequate for a stock cam. I had a 71 RR that would float the valves hard at 5200rpm. That was 20 years ago. When we took the heads off, it looked like it had tiny valve reliefs on the tops of the stock low compression pistons. About the converter, a converter change is one of the biggest performance improvements you can make.

4 decade old springs = bad idea. Even if they've never run, they've been under load for 40 years.

These will drop in and give enough load for whatever you're likely to run w/ stock heads.

Their #1105 spring would probably do well for a lot of applications, too.

When the springs are off, just make sure that the retainers won't smack the tops of the guides. That's NOT a good thing



-Bill

Why wouldn't you run a domed piston with closed chamber heads? I run a set of stealths with KB400 pistons with no issues.