Thread: 'Flat' top high comp pistons?

Originally Posted by up2nogood

Hi guys,
I have a hi comp 4.6 with slightly dished piston crowns and cut outs for valve clearance.
Or perhaps I have a low comp engine.......
Engine number suggests hi comp, but that doesn't explain why the pistons are dished......

Does anyone who has high compression pistons in their engine know if they are true 'flat tops' or if they are slightly dished?

If they do have true flat tops, are their valve clearance cut outs on the crowns?

The hicomps are dished just not as much as the low comp, if they were flat tops they would be around 11-12/1 comp and would ping more than a chinese phone book.

She'd run well on gas though........

Can you get flatties for these??????

mate,, you can get flatties for anything,,,

its just $$$$'s

Has anyone put aftermarket pistons into a 4.6 to increase compression?

And what did it get to?

ok,, we'll try this a different way--

what FUEL do you want to run?

pump fuel?

specialist fuel?


decide that,, do the sums and work backwards.