TA Dreaming

I've gotten my heads and cam back from Ai for my 383 and am working on selecting pistons. I've been reading about DCR and quench etc in an effort to know what I'm spending my money on and how it's going together or should go together. I've been using the calculator found here to calculate DCR for my engine https://www.uempistons.com/index.php...tors&type=comp. I've compared it to other calculators and the values are all close.

From what I've been reading here I need to keep DCR to a max of 9:1 and quench between .050 and 0.035 inches for optimal results in a street engine running 93 octane fuel. I'm having a hard time achieving these numbers based on the parts Ai has sent me to use, and I'm not sure what's the best way to adjust in order to achieve these numbers.

I was wanting to use Mahle flat top pistons with four valve, 5cc valve reliefs as I've heard good things about these pistons. If I do this though, I end up with a DCR way over 10:1 using the gaskets Ai sent and zero decking the block. The only way I can get the DCR down is to use a 0.050 thick head gasket and leave the piston in the block 0.020 inches. That doesn't sound ideal.

I can use different pistons obviously, it just brings me back to not knowing what's the best way to adjust so that I can bring DCR down to an acceptable level yet some how maintain good quench. Is there such thing as going with too thick of a head gasket? Should I definitely zero deck the block and use dished pistons? Does it even matter so long at DCR is achieved? Any help is appreciated.

Relevant info is as follows:
Fully forged 383
6 inch rods
will receive a 4.03 bore
block is undecked so far
currently have 0.026 thick, 4.11 bore head gaskets
57 cc minimum combustion chamber heads according to Ai's info
Cam has a 110 LSA +5.9 adv, intake closes at 61.1* ABDC, and advertised duration is 269.8* Duration at 0.05 is 234.9/244.2 if it's needed.

I did a quick search on Summit just to see what else is out there. DSS makes a piston with a 13cc dish. Combined with a 0.04 gasket and zero decking, I can get a 8.9:1 DCR. Or, use the 0.026 gasket and leave the piston in the block 0.010 inches and have a 9.1:1 DCR. No idea on quality of the pistons. I'm just using them as an example.

So what would you do? I'm probably over thinking this as always.

Thank you!

87Aerocoupe

I think you're confusing static compression with dynamic compression, the LT1 is reverse cooled and can therefore withstand a higher static cr. The LT1 came stock with 10.5:1 static any many 383 builds with flattop pistons and 56cc chambers end up around 11.8 -12.3:1 static cr and use cam selection to get the dynamic cr to 9:1.