So I had bought an lt4 block a while back and with my lt1 spinning a bearing it's time to finish the build. I bought the block pre-assembled block is bored 40 over
speed pro l2256f (+6.10)
stock length rods
stock crank
stock lt1 heads
Do to budget constraints I've decided with the cc503 I was wanting to run at 11.5:1 or higher static compression
the problem im having is that i my dynamic compression is high is 10+ i know many suggest 9.1:1to be the highest to safely run it on 93 oct
so what should i do lower it mill the heads don't really have money for that buy a super thick head gasket or is it safe to run iti may be entering the wrong numbers not sure

 

Milling the heads will raise the compression; not lower it.

Can you provide the specs of everything?
Bore
Stroke
Combustion chamber size
Head gasket bore
Head gasket thickness
Piston dome/dish size
Piston deck clearance

 

If you use the Impala head gaskets, I come up with 11.45 SCR, and 9.02 DCR with that cam and rod length.

Those pistons will not work. The part number is for stock bore, you're 0.040 over..... But I used the dish volume for calculatione with the 4.040 bore.

I'm also assuming stock to spec deck height.

 

The Pistons are l2256f040 (+6.10cc)
stock heads 54cc
i was using stock deck height and i was using .015 found that number on a website that had the info on it haven't got it measured yet
i don't have a headgasket yet been waiting to figure out what compression to run but it will have a 4.100 or high bore size

 

Speed Pro part # l2256f040 = 4.040".

KW

 

Yeah those last three digits make a difference.....

 

Yep....if he'd posted them to begin with .

KW