Yeh but the 4v is a whole different animal. I think carcrazy or jbrew told me I could run flat tops with pi heads and be ok. So im thinking if I can avoid detonation with 89 octane and good tune I wouldn't mind running 10.2-10.4 cr.

 

from what I recall hearing the 4v came with flat top Pistons from factory just as the NPI 5.4 did.

 

I read somewhere that the npi pistons weren't true flat tops, but if they were then I definitely won't hit any clearance issues.

 

I haven't heard anything about them not being true flat tops, but I can't say anything on whether it's true or not. all I know is that I've heard from multiple people that the NPIs run flat tops. maybe they meant flat tops, but not per se true flat tops. who knows.

 

I know what you meant bud. I'll have too look into it more. I won't be starting on this tomorrow or anything.

 

Ok so I went out to the old air port and did a couple of pulls. With stock tune, 34x11.50s, 3.55s, true 2.25 exhaust w/t x-pipe magnaflow, and a trans shift kit this was my best run.



I am definitely getting early shifts at about 4600 RPM's. I should probably start thinking about getting a tuner before anything else shouldn't i?

 

That's probably about what I run with 35x12.50s, maybe a little faster than what I run actually. 4600 is kinda low. All my tunes shift right around 5150 rpm.I would tune it and look into gears before an engine buildm

 

That's the direction I am leaning just to see how it feels. I know my old black truck wouldn't shift until 52 so I'm not winding out in any gear as it sits. Time to start pricing some tuners I reckon.

 

I doubt the still offer it, but I got my x3 with 3 tunes from mpt for like $270. But that's when the x4 just came out so they were trying to get rid of the x3s. I hope switching to 4.56s will make my pig enjoyable enough to drive until I get the funds for an engine and trans build

 

Wow those tires really throw it off or something, exhaust maybe? Probably the combination. It's a 5four right?