96z28t56

Im currently working on putting together my 383, but I think my compression for my set up is a little high

Heres the specs

4.030 Bore
3.75 Stroke
assuming I use a stock head gasket, .049 thickness
Stock 54cc heads (aluminum)
piston deck clearence is right a .02
My pistons are Speed Pro H860CP .30 - which i dont know if they have any negative dish to them, they're flat tops with 2 valve reliefs (4.030)
Im going to be using the LT4 hotcam, and it has the stock lengh rods (5.7)

All together, its some where in the low 12's to 1

Im assuming thats too high for just street use, what can i do to lower that?

Right now im thinking getting a custom gasket from cometic in the range of .080, would that be too much? Also thinking of polishing the heck out of the chambers of the head to get the cc's up a little.

Any suggestions would be awesome

Thanks in advance!!!!!!!!!!!!!!!

Also, what is about the max compression for 93 octane that i could run?

1989TransAm

The piston valve reliefs are 5cc. See what that does to your compression ratio.

RamAir95TA

If you have -5cc reliefs on the pistons, I get closer to 11.7:1 static CR.

Sounds like you're not factoring in the reliefs on the pistons.

95Blackhawk

I run pump gas and race with the LT1 called out in my sig. You need to be more specific regarding DCR and what the use will be. Further, you have not taken into account how programming will help your new motor.

96z28t56

This will be a DD, with very occasional track use.

I found the -5cc's after I posted, which

I get in the ball bark of 11.5-11.7, would that be acceptable for street use?

What else do you need for the Dynamic Compression ratio? I dont have all the specs of the cam infront of me. Its just the GM Hot cam, and i noticed i put the wrong rod lenght in my orginal post, its the stock lenght 5.7" Let me know if i need anything else.

I understand that the programming will help, i just dont know to what extent.

Thanks ALOT!!

94Sleeper

Pretty sure stock LT1 heads have 58 cc chambers.

bombebomb

I am running 12:1 on the street 93 pump gas. 11.5:1 will be great for you, even 11.7:1.

From what iv read, they tend to range from 54-58cc