Re: 289ci Piston Choice
Hmmm, I already bought the pistons, but easily returnable. I was thinking I'd be okay with 11:1 with aluminum heads, 93 pump gas, and the dynamic compression ratio with the cam was something like 8.5:1, I'd have to check again for sure though. The only two other pistons that would work with my heads, one gives a 9.3:1 CR, but it's 20 grams heavier, and does not have the thinner/lighter rings, so i will run into weight mismatch that is most certainly too big of a difference. Then the other was like 8.5:1, flat top, but I think that one was forged, and way heavier also, but could do a lighter pin, I can't quite remember that one's specs because I wanted to bump up the compression some, and believe that was more expensive being forged, and the cost of lightweight pins. I wish I could find a set of used pistons for 9.5:1 or so, but I cannot.
The KB365 pistons are 10.9:1 with a .041 head gasket and .030 in the hole, and 11.05:1 with a .047 headgasket and .020 in the hole, so I think it's a definite 11:1, but I need to measure before coming to a conclusion, that's why I purchased a set, was going to use one and check the depth before installing everything. Thinking I'll run the 0.047 headgasket either way though, as that's 10.7:1 if they're 0.030 in the hole, which is a tad better.
I bought the heads in because I knew they would be good for a stroker motor, plans for the car are a 408/418/427ci windsor, heads might be on the small end, but they were dirt cheap, so porting them will be budget friendly. When I get there, I do not have the money for that right now, that will be after the body work, and change the front suspension. Years ahead of me. But now i'm wishing I would have waited and spent the money on a pair of canted valve heads, because then I would be able to just use a set of stock pistons, and more than likely be okay with stock fly cuts and my cam/head combination.
This is all becoming a cobbled up mess of a motor...
Last edited by 29EssexRat; 05-16-2019 at 10:13 PM.