[chris txstang]

I decided to finally order my parts for the 392. I have a crank on the way, and am going to pick up a short block, probably an early model because I can't find a roller block for less than $500. I will order a rebuild kit from summit and they said I could swap to 302 pistons. My question is will a piston that yields 10:1 in a 302 yield the same in a 392? If not could someone give me specs on one that will with a 60 cc chamber.

One more thing just came to me.... What year did the 351 come ready for roller lifters. I have a set of lifters from a 302, and I will get a new cam, so maybe I can pick one up cheaper than $500.
Thanks

 

[R Code]

Compression in a 393 with a 302 piston will be very high. The 302 has a 3" stroke while a 393 has a 3.850" stroke so a flattop will get you 10:1 in a 302 with a 54cc head while a 22cc dish in a 393 with a 60cc head yields 9.9:1. For most streetable compression ratios in a 393, you are going to need a dished piston.

 

[qtrhors]

A piston that would give 10-1 compression in a 302 would be mucher higher compression in a 392. Piston choice will depend on type valve relief needed...which of course depends on cyl head used and cam used. The FM piston(sold as a sterling piston from summit) pt no STL-H273CP030 could work in your application. Its a hyper piston and is very inexpensive at 11.39 apiece. 10.25-1 compression is what you would have with a .039 head gasket(felpro 1011-2) and a 9.503 deck hieght 351W block using 60 cc cyl heads. A KB hyper piston UEM-KB364030-8 shows 9.9-1 compression they are 282.69 for a set of 8 from summit.

I believe 1994 is the 1st yr of 351w roller blocks

 

[chris txstang]

Thanks for the replies. I guess I will be looking for something between 20 and 25 cc dish. Thanks

 

[RPM]

You may want to look into the KB364 Hyper piston, hard to beat. Several guys on this board are using them.

 

[ville]

Just a word of warning. I am in the process of assembling my 393( SCAT, 5.95 H beams and JE forged pistons. When I preassembled the yet unbored 1972 351 W block with the new crank, rods and old 302 stock size piston I found out that the crank hit the piston and could not turn.I had to grind off appr 1/4" of the btm of this old/fake 302 piston. Now that the block is bored there is no problem in that regard with the new stroker pistons.
Both pistons have 1.600" deck hgt but the stroker piston has less material in the skirt area. So with my modest experience a stock 302 piston cannot be used with a Scat 3.85" crank.
Also there is no hope to get the stock windage tray to fit with the CAT main girdle, oilpump area needs some grinding as well as the girdle, the main saddles need also to be touched with the grinder.These all are small but necessary steps.