Long skirt SBC pistons
I picked up a running motor from 89 F-body that made some slight internal noise. So I decided to take it apart to evaluate the condition. The engine had some performance work done to it. The engine had about 2000 miles on it so it's very clean inside with no build up what so ever. Oil traveled well into the heads via push rods. Now when I removed the pistons (block had no ridge yet or any scoring), I noticed two pistons #3 & #7 had the outboard skirts broken about half inch up from the tip of the skirt. The broken pieces where in the bottom of the pan still in one piece, no shavings. So I figured pre ignition or detonation did it. OK, I get the local engine builder chase me a couple of slugs. No problem he says, those are 345 NP. Well, five samples later and they cannot match the pistons. Obviously the engine have been rebuilt. Two bolt mains, one piece seal crank, 14101083 (64cc) heads ported and polished, aluminum roller rockers, flat tappet cam with gears not chain. The pistons have H 1479 96 casted on the inside. Pin diameter 0.927", compression height of 1.560", rod length 5.700" and an overall piston length of 3.220" The new pistons the jobber received average about 2.610". According to some piston manufacturers, the zero deck height with these heads give me about 9.7:1 cr. That's good for street performance using pump gas. BUT, what are these pistons and why do they have such a long skirt? Hate to buy a new set, but if I have to, then so be it. Anybody familiar with these pistons? Thanks.