Idyllicidiot

I have a stock '97 GT Conv., I was planning on doing a PI swap but I heard that the heads off of a 94-98 Lincoln mark viii will bolt on. Wondering if it's true, if so what else would be needed to do the swap.

EddyG

go with the PI swap you wont regret it. it may be a little pricey unless you do the work yourself. you can get good heads, cams, intake from a 2001-2004GT for about 300-500 depending on the mileage. you will also need the valve covers for the new heads also. do the PI swap like i did. before the swap i was around 190rwhp and thats with some little bolt ons. now with the swap 281rwhp and 318rwtq. and if you decide to go that route when you get the heads polish them and clean them up will make a big difference.

trailor

the mark viii heads aren't a necessarily a direct bolt on as opposed to a PI swap. theres a 4v swap write up on here somewhere, research that and you can figure out if its worth the time and effort

5sp04GT

U gained almost 100 rwhp just by doing the pi swap y doesn't that sound right. Do the non pi heads really restrict that much?

Rockwell28

I think he went with different cams not PI cams and his heads were polished. a non pi bottom end with PI heads and cams will make more than the factory PI motor bc of the piston difference and the bump in compression with the PI swap.

https://mustangforums.com/forum/4-6l...ang-dynod.html

5sp04GT

Ok I guess I just wasn't expecting those kind of numbers out of a seemingly simple pi swap... Maybe 20 or 30 rwhp. Just didn't sound right to me but then again I'm not exsperianced with non pi cars.

EddyG

Yes I went with comp stage 1 cams and I got the 04gt heads polished when I baught them. But if you just went with the PI cams and didn't polish the heads you can make 250-265rwhp easily. I say it's the best thing to do.

sn95_331_GT_ yellow

keep in mind that NPI shortblocks have -11cc pistons, 4V motors have -3cc pistons so doing 4V B heads on an NPI block will give you factory compression, not the 10:1 that 4V motors have stock

4V shortblock + PI heads with cams = WIN