Carguy3

I am interested in anyones comments regarding the performance of your car after adding these heads to your 1995-1998 Mustang. Do you have to switch to 93 octane fuel? Any problems encountered during the inatallation.

98MustangSTL

Yes. You want to run higher octane gas with the increased compression. Whenever you add P.I. heads to a non-pi block, compression is increased.

phalcrow

Weh I did the PI swap I was able to run 87, but it did ping sometimes. Otherwise very drivable. Now I have to run 93 with flat top postins.

ripper

when i got my pi motor built i had forged 18cc dished pistons installed in the stock romeo blk. My compression is 9:1. Watch out for that ping. Ping usually means detonation and that will def break somthin. If your not planning on a blower 10:1 is ok. Actually spray likes compression so after you do the swap start savin for nos. [sm=nxsmile.gif]

NYTMARE

What 1/4 and whp numbers are you guys that have done the PI swap at??

SXGT

i think its 270 bhp

II 98 GT II

96-98