Now what?

[Randra]

Okay tore the heads off my 66 383. As I suspected the builder installed the wrong pistons. They are at least .45 down from the deck with 906 heads on it. So my compression ratio has been very low this whole time.engine was rebuilt in 92 it always ran well but it's more of a noise maker. I wanted him to build it as a 68 hp so I could use my 68 heads and intake. So the damage is done. What can I do with the heads too increase the compression or what head should I be using instead.

 

[62 Dart Convertible]

You couldn't modify the 906's if you were thinking of milling off enough to make it happen.

Installing closed chamber heads and a thinner head gasket is way to go.

Here is a handy CR calculator -

http://www.summitracing.com/expertadviceandnews/calcsandtools/compression-calculator

 

[mopar 3 B]

Change the pistons and keep the heads.

 

[Randra]

Ok now I'm confused I tried that calculator and I just don't understand it. It's a 383 everything stock except bored 30 over. Should I go with the 915 closed chamber. Or can I find something else.i don't really want to change the piston unless I really have to.

 

[Cranky]

If you're getting around 8.25 compression ratio with a composition gasket, then you're probably in line. A closed chamber head will put you close to 9-1. What is the engine being used for? A 915 head would definitely help but are usually expensive. 516's are also closed chambered but usually come with a smaller exhaust valve and the ports aren't as good but they can be made to work well. How much do you want to spend and how fast do you want to go. Low compression engines can be made to run pretty well if the combination is right.

 

[Randra]

It's just a driver. Just want to cruise. I just wanted it to resemble a stock 383 magnum when it was rebuilt. I'm on a low budget. Just looking for that right combo

 

[Cranky]

Do you know what cam is in it?

 

[Randra]

Refere to post. what's your opinion I've got a pic of the specs

 

[Cranky]

If you have a pic of the cam specs, post it up....

 

[Randra]

Go to my post( what's your opinion ?) I've got a pic there.

 

[HT413]

Go to my post( what's your opinion ?) I've got a pic there.

I think the confusion here is that you started another post while you were getting plenty of good advice on the other post. If you're looking for free advise, you might have posted a link to the other post or just never started this second post in the first place. Not trying to sound smart here, just trying to help.

There's a builder here IQ52 that has done wonders with low compression engines. Search through the threads he has started just for a little confidence boost in your existing combination.

You say you're on a budget. Are you set on keeping the stock intake and exhaust manifolds? Are you set on keeping the cam?

You say the pistons are .45 down. that's almost half an inch, so i assume you mean .045. Did you enter it correctly in the calculator or did you enter the .45? You also say 'at least .45'. go to harbor freight and buy a $15 caliper and get a closer measurement. then enter THAT into the calculator and see what it comes up with.

 

[MarPar]

Supercharger!!!

 

[Randra]

Excuse me but I'm new to all of this. Ok I forgot to add a zero to that number. I said at least because I don't have the proper equipment too measure it. And you could easily be off when just turning the engine by hand. I've got other post about the same issue and as I'm getting into it I have new info about it. Didn't think I couldn't start another post about it ,sorry. And free advise is what this site is about isn't it. I'm not great with computers as I'm not great with engines. Can you tell?

 

[62 Dart Convertible]

If your bore and heads etc are in good condition, then the right pistons would likely be the best solution...

 

[Randra]

Thanks, I need to have the heads rebuilt has burnt valves. But other than that everything is fine. I want to keep it as stock as I can. Was also thinking new pistons would be in my best interest. Unless I go with a closed chamber head. But I don't know Which one to use.