tofasgt

I have a 96 gt with PI heads and Intake along with many other mods and was just wondering with the Comp Cams XE274h cams would I have any piston to valve issues or do I have to fly cut the pistons?

oxfordgt

Yes even with degreeing the cams you will on a 96. 99 and up not so much but the flattops in the 96 are what is going to cause it.

tofasgt

So there is no way I can run these cams without fly cutting the pistons? What are the biggest comp cams i can run with PI heads?
and also the best sounding lopey cam? how do you go about fly cutting the pistons any detailed info.

ben790450

VT stage 2 cams. No Piston work needed.

Flyingmau5

Need valve springs though....

97targa

The lopier the sound the less streetable it will be! Those are for high revving applications only. They will have big torque loos down low and you need 3000rpms before they begin to create the power. I would go with comp 102600 xe-270ah (stage 1)1800rpms-5800rpms or the comp cams 102700 Xe-278ah (stage 2) 2200-6200rpms Both of these with no probs, but the stage 1 can use your stock pi springs while the stage 2's you should really replace them
OHH, BY THE WAY the xe-274's are for non pi heads with only a .500 lift! You donot want them.. You could run them with no problems, but you would lose power from what you already have! It would be basically same as non-pi heads with a cam install! LOL

droptoppony

NPI 2V's don't have flat tops...they are 9cc dished compared to PI that are 16cc dished. You can have a 30cc dish and still have PTV since on 4.6 pistons the contact happens on the outter ring not in the dish.

Original poster:
like said above, why are you going with cams for NPI heads?
If you want a really nice set of cams that will give you power go with the Crower st 2 NA.

97targa

the npi blocks had 11cc dish pistons with 51cc heads and the pi blocks have 17cc with 42cc heads. The 4 valves were the ones with nearly flat top pistons measuring 3cc's!

tofasgt

so i can run the xe274h cams with no prob. right? and i ordered these cams before i decided to do the PI swap but if there gonna hurt instead of help I think i will swap!
thanx guys!

97targa

YES SWAP THEM for a set of XE-270 part number 102600. You will not gain much of anything if the lift is only .500 The whole reason for doing a PI swap is to get that extra lift for air flow to .550 lift! Those cams do not match those heads!!!!