mavman, these pistons have a ch of 1.602. If I use a newer 9.503 block the pistons will be .020 in the hole. This actually works in my favor as the compression is going to be quite high in the end. I've tried to calculate the cr but I don't know the volume of the stock boss dome! I have all of the other numbers to figure cr. I have attached some pics of the pistons. What is the distance from the pin to the skirt in your pic with the arrow. It looks like these could work! what do you think
if memory serves me correctly, the factory boss pistons were made by TRW. I think the compression was 11.5:1 w/58cc heads. This should come out to roughly a 10cc dome volume, give or take. If in fact they are 10cc, with -.020 deck clearance and 58cc 4v heads, you'll end up with around 14.3 to 1 compression. A bit much for pump gas I'd say, but it should scream! with 76cc open-chamber 2v heads it would be around 11.2. A little bit better for today's cat-pee gas!
I didnt measure the distance you're looking for. They did not hit the skirts anyway, they hit the bottom of the pin area. Thats where they had to be ground. I'd bet yours will also have to be clearanced, but dry-assembling the shortblock will be the only way to find out
I meant the bottom of the pin area. I didn't want to start investing in stroker parts but I guess the worst that can happen is I would have to buy the SRPs you listed! Did you include the gasket volume in your cr calculation? When I do that I get 11.06:1. Still to high! If I shaved the dome it would be 10.14:1, much better.
what head are you using? Open-chamber 2v cleveland heads? I wouldn't go over 10:1 with those! The open chambers tend to help detonation get started from what I've seen/heard. I didnt know what heads you're using--but the SRP's I used are for stock windsor-style inline valve arrangement, not the cleveland/boss "canted valve" arrangement. Oh, and yes, I included the gasket thickness, .040" compressed. Also used a .030 overbore instead of standard.
yes, I'm using the open chamber heads (2V). If I go to the SRPs I would go with the standard windsor head! Though, I have an old article stating if you stay below .470 lift you can run boss heads on the stock 302 with the windsor pistons. Not really that useful, but interesting. In that case you need either the 4V heads or the australian closed chamber 2V heads (also sold as SVO heads in the states). It was just an idea that I may not pursue, would be interesting!
if it was me, I'd go with the light SRP's, performer RPM or Victor Jr heads, RPM or Jr intake..etc etc. These 393's are great engines when built right--they have a very wide powerband (mine was 3300-7800). With a smaller camshaft, they'd be pretty docile on the street, but extremely torquey! I know a guy that builds engines for a living, and a customer of his needed something for hauling heavy loads. He didnt want a 460 because the weight of the big-block could cause the front tires of his truck to plow into mud and get stuck, so they build a 393 instead. From what I'm told, it is the fastest hay-hauler in arkansas!
cani get a little advice on this topic. Im building a twin turbo 351 windsor. Goa a cheap set of scat h beams. Am putting low comp pistons in and new steel crank. Was gonna go standard stroke but am thinking bout stroking it with 302 pistons to utilise my h beams. Will i be able to get 8.5 comp woth 302 pistons and 393 crank?
