Flat top pistons?

Topic: Flat top pistons? (Read 918 times) previous topic - next topic

Flat top pistons?

August 10, 2006, 12:37:53 PM

Just something I wonder about now and then. I've read on coolcats that the stock pistons won't work with performance mods like super charging or even a stronger cam than HO which is what I'm using now. A supercharger isn't too likely at the moment, neither is a cam change since it's lots of work and I'm lazy :hick: But I might be looking into 1.7 roller rockers later on which will increase the lift of the valves. Should I worry about that? Just what are the differences between my pistons and the Mustang HO pistons, I know they're dished but are they cut lower for more clearance? Is there a compression issue? I haven't seen 5.0 Mustang pistons up close but I've seen 94 3.8 pistons which were dished and judging with my eyes, the dish displaced about as much as the 4 valve reliefs on my stock pistons. Just curious.

Flat top pistons?

Reply #1 – August 10, 2006, 05:45:32 PM

'85 to 92 Mustang pistons were forged (the HO rollers) and from 93-95 they used hypertuecitc (or however it's spelled;) ) pistons. If you have valve reliefs in your pistons I *think* you should be ok with 1.7 rockers. You'd have to measure piston to valve clearance to be sure though. The Birds and Cats with a 5.0 from 86-88 had cast flat top pistons with no valve reliefs.

Flat top pistons?

Reply #2 – August 10, 2006, 06:05:28 PM

A few people have reported running an E-303 cam with the stock 1986-88 Cougar/T-Bird 5.0 block, and not having to have pistons with reliefs. Obviously every motor is different, and you should always measure first, but you might get lucky. I think your pistons have reliefs cut in, don't they? You're still running the 1983 block?

Flat top pistons?

Reply #3 – August 10, 2006, 06:25:09 PM

i wouldnt try it myself. some people dont know what they really have so they may accually have had vale releifs.

hypereutectic

Flat top pistons?

Reply #4 – August 10, 2006, 06:26:25 PM

Yep. Still have the 83 block with stock crank and pistons. My pistons have 4 valve reliefs cut into them, though obviously 2 of them aren't good for anything. I had to scratch my head on that one when rebuilding the engine....

Flat top pistons?

Reply #5 – August 11, 2006, 10:34:35 PM

The cylinder heads you run also have an impact on the cam you can run with flat top pistons. TFS heads with flat top pistons give plenty of clearance for a lot of performance cams. Which heads do you plan on running?

Flat top pistons?

Reply #6 – August 12, 2006, 12:50:14 AM

I'll probably have the E7 heads for a good while yet, atleast until I get a good deal on some GT-40 heads.