351W - 396 stroker piston question

auto10x · #1 (**permalink**) 03-20-2003, 11:09 AM

I plan to stroke a 351W to 3.850" using rods that are stock in length. I understand that longer rods would be better, but I've already got Eagle H-beams and don't really want to spend more to get longer ones. All that being said, I've been looking at KB pistons and wondered what 302 piston to use. I will be using GT40X heads. I'd appreciate any wisdom on this subject. Also, I had the Hot Rod article w/ part numbers for the pistons in the 392 crate engine but can't seem to locate it. Does anyone know what piston they used. I think it was a Federal Mogul piston, but not sure.
Thanks.
Bill
auto10x

Leo · #2 (**permalink**) 03-20-2003, 11:49 AM

auto10x,

The logic behind the 3.85" stroke was to use stock length 302 rods and 302 pistons without clearencing the stock 351W block. Upgrading the rods or pistons can be done as well as long as you are using stock dimensions.

A long-rod engine is another issue altogether and probably not feasable if your primary goal is to increase cubic inches. There is a school of thought that the benifits of a long-rod engine are often over-rated. In my opinion, if you already have 302 length H rods, don't give the long-rod issue another thought.

I did not read the mentioned article so I can't help you with part numbers or manufacturer's. However, it sounds like you're putting together a good combination.

TerrysSPF · #3 (**permalink**) 03-20-2003, 11:57 AM

Bill: The 392 crate engine uses Fed Mogul PN H132CP-30 pistons. Piston rings are Grant PN CC400H030 or Speed-Pro PN R-9902+030. Hope that helps, and good luck with the build!

auto10x · #4 (**permalink**) 03-20-2003, 12:26 PM

Thanks for the information, much appreciated
Bill
auto10x

Mr.Fixit · #5 (**permalink**) 03-20-2003, 01:44 PM

Longer con rods are better. But saving the money and spending on your heads may yield more additional power for the dollar.

tim · #6 (**permalink**) 03-20-2003, 05:21 PM

To clerify Leo's coment on the rod length. You need stock length 351w rods 5.956 not 302 rods. As for piston choice, use a compresion calculater with the specific information on the parts you already have ( combustion chamber, stroke, head gaskets, etc...) and try the different piston configurations (+/- cc's) until you hit on one that gives you the specs your looking for.
Tim

hound dog · #7 (**permalink**) 03-20-2003, 06:10 PM

Another item to be VERY careful about. If you buy a 10 1/2 to 1 302 piston you will get about 11.9 to 1 with the 393 stroke. You may wish to start with a 9 to 1 302 piston and calculate your compression ratio very carefully after you find the volumn of your combustion chamber and the thickness of your head gasket. Been there done that, screwed it up, still got lucky!

h dog

auto10x · #8 (**permalink**) 03-22-2003, 12:49 PM

Thanks for the info guys, appreciated.
auto10x

Scott S · #9 (**permalink**) 03-23-2003, 06:25 AM

I used Keith Black # KB 192, you can use this link to determine which dish is correct for you heads.

Compression Calulator

Scott S

auto10x · #10 (**permalink**) 03-24-2003, 04:39 AM

Scott,
Thanks for the piston information. When you used the KB 192 piston, what compression ratio did you end up with? Was it calculated or measured?
Thanks,
Bill
auto10x

Scott S · #11 (**permalink**) 03-24-2003, 05:41 PM

I haven't measured it yet, but the calculated ratio is 10.2/1

Thats with 64cc combustion chambers on my Windsor Senior heads.

Scott S