Gibbles

This winter I'm planning on pulling my engine for a refresh.

While planning this I'm thinking about doing a 383 stroker...

Using my heads (70cc chamber aluminum heads) and forged pistons available, it seems I might end up a bit limited on options...

Think a Dynamic compression ratio of 8.32, and a Static of 10.08 will be ok on pump gas?

(I'll have many more questions as I get closer )

Gibbles

also the best I can find for pistons has a +6.40cc valve relief, if I could get it closer to 8cc it would be right where I want it...

rklessdriver

I am not sure how you are calculating DCR but thats a pretty high number for only 10.0 SCR.

Honestly 10.0 SCR sounds optimistic with 70cc heads and 8cc pistons... you would need to be zero deck with a .039 4.166 (Fel Pro 1010) gasket to get 10.03SCR. Switching to 6cc pistons only gets you to 10.25... even a stock L98 cam will run fine on 93 octane with that compression ratio.

Depending on what rod you want to use Wiseco has some 7cc flat tops that are very affordable, around $450 a set including rings.
Will

Gibbles

Well I'm actually looking at some 6.4cc flat top pistons.
if i could fimd some forged 8cc pistons i would be right where i need to be.
7cc pistons are closer, but not a huge difference in the numbers.

Maybe i need to entertain the idea of a cam swap, my current cam i replaced about 2 years ago...

Mostly I'm trying to talk my self into a 383 usimg my stock rods, adding a 383 crank, and new pistons.

Gibbles

As my car sits it's a hoot to drive, i giggle every time i leave a black patch behind me...
I'm thinking stroking the thing will help it hit my converter that much harder.

when i did the build originally i was being told to keep the DCR below 8..
​​​​​​​However it's possible they thought i still had the original heads...

ddahlgren

Just flat mill the heads 0.015 and you are easily there as normally 1.5 cc per 0.010 cut off. If 70 cc and aluminum they must be aftermarket so plenty of deck on them to mill.

cv67

milling is simple and cheap. i took over 10cc out of mine no issues

Gibbles

Heads are edlebrock, should have a 9/16 deck if i remember correctly.

​​​​​​​However i need to add cc to the combustion chamber, is that something a machine shop will do?

cv67

Yes a qualified one otherwise they may ruin them
Look up Straussberg machine in UT they are incredible
email tpi421vette@comcast.net aka tpi421vette he will guide you. Trust me you want his help & will be glad you did.

BlowerWorks

No less than 9:1 !!! Better 9.5:1 !!!! Best 10:1 or better !!!!!!!!

Gibbles

​​​​​​​Nice, thanks!

ddahlgren

You used positive numbers for the piston that infers you want to reduce ccs in chamber / combustion space. Which one is it. With what you have is the compression too high or too low? If you have nothing with the 6.4 cc pistons what is the compression ratio (static please)

Gibbles

So as i understand it (from looking at pistons),
+cc means its adding to the combustion chamber size.
Like a flat top piston with two or 4 valve reliefs.

-cc would be subtracting from the chamber size.
​​​​​​​Like a piston with a dome on top sticking up.

ddahlgren

You had me confused with what you are trying to do. I had thought you wanted to raise the static cr. 10/1 seems a bit low to me I would be thinking 10.75/1 and a bit more cam if even borderline serious. 11/1 would not terrify me unless a tpi.

Gibbles

Yeah, i could have been a little more clear.

That high DCR has me worried, and i hate to spend more than i need to, however i would like a different cam that is a little more high rpm friendly.

With the heads i bought, i have to be careful to not go past .550 lift with out having the spring pockets machined (per edlebrocks instructions).
right now with the camshaft i have + the 1.65 roller rockers i have i'm @ .500 lift (or just a hair shy).

My heads are the e-street series, springs included have limitations...

I'm willing to spend the money, this car is totally my "happy place" right now... However i do want to watch the spending...

​​​​​​​if the cost goes to high, i might have to hold off until the summer...

ddahlgren

How good is the knock sensing in your ecu?

Gibbles

ecu = ebl flash
I can play with some settings if need be.
​​​​​​​As it sits, i have the knock retard disabled @ idle...

Gibbles

And the knock sensing is pretty good, while data logging i can see it picking up some bumps...
but i do have the iinfamous 84 Z51, drives like a gocart, and it will try and send you through the roof over bumps..

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