Thread: 3.4 or 3.5 with headers

Im ready to order my pulley, and im trying to determine if I should order a 3.5 or 3.4.
Its a 2002 GTP with a gen 3. At this point everything is stock except the open cone.
I am installing Speed daddy headers, autolite 104 plugs, maybe a tstat, I have an open cone intake,.
The car has 0 KR now at stock. It is also not my daily driver, its my play toy.


I thought before I spend the money id get some input.

3.5 or 3.6.. once you get some rockers or a cam, then you can drop.

And monitor KR

Im guessing with a 3.5 (if I don't knock) Im looking at maybe 25-30 Whp?

You can guess around that if you'd like

Only way to know for sure would be dyno.

By lowering the size of the pulley, you increase your cylinder air temps a lot. Since winter is nearly on us.. you can get lulled by the cooler air keeping you running semi knock free after that pulley swap. But.. when summer comes..you might meet Chip.. Scott did, and I kinda told him the same this time last year.

its going to get an IC before summer roles around

Originally Posted by BillBoost37

By lowering the size of the pulley, you increase your cylinder air temps a lot. Since winter is nearly on us.. you can get lulled by the cooler air keeping you running semi knock free after that pulley swap. But.. when summer comes..you might meet Chip.. Scott did, and I kinda told him the same this time last year.

you sure did, and you were also 100% right. but i was re tuning as the temps rose. then the FUEL PUMP TOOK A CRAP! i was done tuning when it popped on me. it was kr free.

Problem with me is..I'm not pessimistic, I'm experienced.

well when the pump dies 100% in less then a 1000 miles from the engine swap, theres your clue.

If you say so.. I've had pumps die and never wipe out an engine

its all i can come up with. as it died soon after. and my fuel trims went up after the new pump. i say that 233,000 mile pump ran its course and died on me.

I flipped a coin it landed on the 3.4 side, then I ignored and bought the 3.5.

.1" doesn't really matter.

So i just re-scanned the car, scanning app wasnt working right the first time.
Found out average KR is .5, peaking at 4 at the shift. Am i still safe to do the 3.5 and headers colder plugs and the tstat

yes, your stock as far as i can tell.

headers should kill all your kr, the pulley may add some but you should have a tune for it, to get the most out of it safely.

so i guess my next mod would be getting DHP

that or a canned tune at least.

I did 3.4, anything bigger is for babies