98 gt with pi heads

[Bolt on 5.0]

I have been looking at newer 4.6l mustang and have seen a few 96-98 I like. I know if the heads are switched on these to the new pi heads it raises the compression ratio. I there a way to keep the compression down without changing the pistons? Thicker head gaskets?

Do any of you have luck with a thicker gasket running a supercharger, and are there any of you running a charger with the higner compression. Reason I am looking at these years is because the price range is much lower than the 99 and newer. Thanks

 

[Bolt on 5.0]

no one?

 

[TweekedGT]

The one thing guys do instead of the full PI swap is just swap to the new PI intake. There are adapters you can buy or you can use silicone to fill in the gaps. I know there are a few guys on here that have done it. It won't give you the full PI horsepower like the headswap would but it is supposed to be really close. You won't have the compression problems that way.

 

[mrvax]

The PI intake and cams is probably the best way to go. Alternative is to have a good shop cut out the swirl dams on the PI leads. Some have done this successfully. If I was going to supercharge, I'd just do the PI cams and intake.

 

[Bolt on 5.0]

Well dont they make a better than pi intake aftermarket. And if I am investing money I will invest into some aftermarket cams as well.

 

[Mel96GT]

Well dont they make a better than pi intake aftermarket. And if I am investing money I will invest into some aftermarket cams as well.

Not really. For the money ($170) you cannot beat the stock, plastic PI intake from 2,500 to 5,500 rpm range. There are other intakes such as the Bullit and others but they cost several hundred dollars, and they usually only out-perform the PI intake significantly at 5,000+ rpm's.

 

[stangGT97]

Cometic makes CR reducing headgaskets, I know a couple of people are running them with PI heads on stock 96-98 shortblocks, + boost. I'm not sure of the thickness though. In all honesty, the power gained from the PI heads vs. just the PI intake and cams comes from the increase in compression. If you reduce the compression, then it will really close the gap between the two. I would slap on a PI intake and install some blower cams if you're going for boost.

 

[john356001]

The one problem that occured to me was that when you run a thicker head gasket you put more stress on the timing chain cam gers etc. also the thicker head gasket throws off valve geometry etc. You need a signifigantly thicker head gasket to get back to stock and those extra .001 can cause your timing chain to let go prematurley.

 

[Gearbanger 101]

The one problem that occured to me was that when you run a thicker head gasket you put more stress on the timing chain cam gers etc. also the thicker head gasket throws off valve geometry etc. You need a signifigantly thicker head gasket to get back to stock and those extra .001 can cause your timing chain to let go prematurley.

There's more than enough slop in the timing chain to compensate for any reasonable increase in height and for cases where height would decrease (in the instance that the heads were decked), the tensioners are more than capable of taking up the slack. So wiping out the cam/crank gears even over time is really a non issue. In theory, your argument does hold some merit, but in reality, engine tolerances aren’t anywhere near that precise that it would affect cam timing to any significant extent. You'd have to increase or decrease deck height considerably for it to become problematic, which isn't practical.....or likely even possible.