Looking for a set of 390 std pistons for the build, but having little difficulty solving my compression ration with hypereutectic pistons.

I am looking into a 10 to 1 ration for my build, but not quite sure about the piston choices as websites won't specify the cc volume for the piston dish. I've looked into forged pistons, but somewhat skeptical buying them.

My piston to deck clearance is 0.032 and thats with 1.76 compression distance of the piston.

I am looking into Steve C book and some of the "piston to deck clearances" are pretty impressive such as .010 or lower, which will give .4 more CR. I know some might say that .015 piston to deck is plenty, and I would agree, but hypereutactic pistons do not give this option.

I do not want to deck my heads below 68cc. so far I have:
bore 4.050
stroke 3.78
68cc head
compressed gasket thickness .040
head gasket bore 4.050
piston to deck .032
dish relief +20 cc (I think it is a standard for hypereutactic pistons)
CR = 8.73

I need more cc from the piston dish (+10 would do) and less piston to deck clearance ~ 0.015 and I would be a happy builder.

Any advice would be helpful.

Nick

 

I like the self-answering posts. I found some information on the piston CC's. Wonder if someone is aware of it.

Brand Part # Piston Style Compression Distance Pin Diameter Recessed area CC

Sealed Power H395P Flat w/4 reliefs 1.759 0.975 6.0 cc
KB Silv-O-Lite S1131 Flat w/4 reliefs 1.760 0.975 8.0 cc

KB Silv-O-Lite S1116 Dish w/4 reliefs 1.760 0.975 .073 deep by 2.690 Diameter 9.5 cc
Sealed Power H304P Dish w/4 reliefs 1.759 0.975 .080 deep by 3.220 Diameter 12.0 cc
KB Silv-O-Lite S1130 Dish w/4 reliefs 1.760 0,975 .147 deep by 3.000 Diameter 19.0 cc

KB Silv-O-Lite S1139 Dish w/4 reliefs 1.660 0.975 .075 Deep by 2.260 Diameter 9.5 cc
Sealed Power 381np Dish w/4 reliefs 1.660 0.975 .097 deep by 2.620 Diameter 11.7 cc

Nick

 

Personally I wouldn't wish hypereutectic pistons on someone I don't like, the higher silicon content makes them a little tougher but they can't handle any more rpm than a regular cast piston.
If it's just a daily driver put cast pistons back in, other wise go with a set of forged pistons.

 

My 428 cj doesn't get driven hard but I felt the forged pistons were worth it.