If I get them I'll probably put them on a 1985 8.13:1 engine I have here. Should be a good upgrade, no?As the engine was originally 8.31:1
I'm getting a bit confused with the advice here and other forums (my fault, no one elses). If they have the composite gaskets they remain the same compression on a 3.9/4.0/4.6 but if I use them on a 3.5 (1985) with a tin gasket there'll be a compression bump of about .6? That's really the only reason I'd get them, to bump up the compression on the 1985 8.13:1....Not much point otherwise from what I've read.....?Those castings - HRC2479 - also came on 3.9L engines, but they are the smaller combustion chamber types, so need composite gaskets. I have a apir on a 8.13:1 3.9L engine.
If I get them I'll probably put them on a 1985 8.13:1 engine I have here. Should be a good upgrade, no?
That is an option - but with the 4.6 heads and stock pistons it will be a touch over 9:1 which is just fine, and the more I think about it the more likely this will be the plan.Can't you rebuild the better engine with HC pistons? 9.75:1 and rings are less than £250 new.