Used Heads On 98 GT
 

Hey...I was reading over the Headswap thread and began to wonder something...can you take the stock heads off a newer model GT and will they bolt up to a 98 block (with new seals). We have a local mustangs only junkyard that auctions off wrecked cars for vultures (like myself) to scavenge. I was just wondering if I could take the heads off a newer model and fit them on mine.

If I remember right there are some differences in heads. I think if you swap the 99+ heads on a 96+ car your compression ratio will be pretty high.

Do a search in there forum on this subject, It must have been discussed before.

The 99 up heads will fit perfectly on the 96 - 98 block. The compression ratio goes up but will not effect it unless you want to go to blower or nitrous, then you have to get the piston , crank upgrades. With the higher compression I think you need to run premium gas. Also, you have to have the 99 up intake, move the oil dipstick, and heater hose. The best heads for the upgrade are the 2001 heads, they breath the best They should gain you about 50 + RWHP.

I think 50 RWHP is awefully optimistic, 60 HP at the crank is way more realistic.

All 99+ PI heads will drop onto your block, you will need all the other parts to complete the swap, a good list is here:
Parts List
I went with used heads because I am not going to use the oem valvetrain, I am replacing valves, springs, and cams. You should have used heads inspected and tested by a machine shop before installing them or putting any money into them. If I were not going to replace the oem parts and just use the stock cams, valves and springs I would have went with new heads. 2001+ heads can reuse the 96-98 valve covers, you will need valve covers if you use 99 or 2000 PI heads, also, I think most kits are using the 2002 intake now, since there is a place for the drivers side temp sensor to be drilled and tapped.

btw, I believe the advertised flywheel hp ratings were 215hp for 96-98 (may be 225 for 98s???) and 260hp for 99+. So your gain should be in the 45hp range with stock PI heads, you may get a bit more with a bump in compression.

You are correct about the 98, it saw a 10HP increase due to "Hotter EEC Tune", or, so the reviews and articles state. It was the only one rated at the 225HP mark, all other SN95 GT's (96/97) were 215HP