98 Gt Pi Swap Hp

Khenji Harris

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With a pi swap, full exhaust, long tube headers, full bolt on and Bama race tube, is 280whp realistic for a 98 gt?
 
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Dark04GT

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With a pi swap, full exhaust, long tube headers, full bolt on and Bama race tube, is 280whp realistic for a 98 gt?

Full bolt ons (full intake and exhaust), pi heads, pi cams, and pi intake will get you near that power level assuming you have npi pistons (that you have the stock motor for your year) that increase your compression ratio. More aggressive cams / porting those pi heads would more comfortably put you in the 280 rwhp range or higher. I would take advantage while you are working on the swap and plan what you want to do if your budget allows it.
 

Khenji Harris

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Nov 14, 2016
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Full bolt ons (full intake and exhaust), pi heads, pi cams, and pi intake will get you near that power level assuming you have npi pistons (that you have the stock motor for your year) that increase your compression ratio. More aggressive cams / porting those pi heads would more comfortably put you in the 280 rwhp range or higher. I would take advantage while you are working on the swap and plan what you want to do if your budget allows it.
Preciate that, I was contemplating between pi swap or just putting an aftermarket cam in it. I was under the impression that labor and parts for a cam job would be cheaper and after a tube could put me in the 250-260whp range?
 

Max22

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Jul 1, 2015
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You can reach 300 rwhp. I took a stock 96 gt engine. Threw on cat back exhaust, cut out the cats, LTs, full K&N CAI, 75mm throttle body and plenum, then lastly did the full PI swap. Did a couple pulls on a Mustang dyno (they read low) and got 298 hp and 322 tq. That was no tune and just running on 91 octane pump gas.
 

Khenji Harris

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Nov 14, 2016
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You can reach 300 rwhp. I took a stock 96 gt engine. Threw on cat back exhaust, cut out the cats, LTs, full K&N CAI, 75mm throttle body and plenum, then lastly did the full PI swap. Did a couple pulls on a Mustang dyno (they read low) and got 298 hp and 322 tq. That was no tune and just running on 91 octane pump gas.
Wow how much did the pi swap cost in parts?
 

Max22

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Jul 1, 2015
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I lied it was 293 hp and 325 tq
 

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Max22

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Jul 1, 2015
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Well I was able to get like new heads for $300. Intake $75? Head gasket and head bolts about $100. Then factor in the possibility that your timing chain is worn. Timing cover gasket was around $20 for a felpro I believe. I installed a different thermo stat either the 160 or the 180 (which ever the PI's run with idr which) $10. Intake gaskets another 10 or 20. Then figure another $20 or so in misc bolts you break or are too chewed up. And lastly of course new coolant, an oil filter or two and a couple gallons of oil (to catch all the debris afterwards). So ball park $500. It all depends on where you buy your parts and if you go used for the heads or intake. I wouldn't suggest getting any kits as it's cheaper to piece it together yourself. Harder than a cam install? Yeah. Way more beneficial $ per $? Most certainly.
 

Max22

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Jul 1, 2015
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Yes, in my case the PI cams were already in the heads. A lot of people go with just a used set from a junkyard but that's all up to your budget and preference. No as far as hp and torque go you are far from the limit. If you have a manual t-45 I think it's rated at 450hp and I dunno how much torque but as long as you don't drag race with slicks you can boost and you'll be okay.
 

Khenji Harris

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Nov 14, 2016
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Yes, in my case the PI cams were already in the heads. A lot of people go with just a used set from a junkyard but that's all up to your budget and preference. No as far as hp and torque go you are far from the limit. If you have a manual t-45 I think it's rated at 450hp and I dunno how much torque but as long as you don't drag race with slicks you can boost and you'll be okay.
Nice, I guess I was thinking of when people boost stock npi motors and the motors can only handle up to 350whp before breaking, but I guess the pi heads give more strength or was I just misinformed in general?
 

Max22

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Jul 1, 2015
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That's mis information and old threads. I've heard of people running over 400 to the wheels with boost and a stock bottom end. Now personally I wouldn't do it without forged internals but the block can most certainly take it. Our engine is old and tuners have had a lot of experience with them by now. If you can find a good tuner you can do crazy stuff even with the stock parts. As far as Bama goes once you go PI swapped DO NOT run any of their factory preset tunes as they are not set up for it and could very well blow your engine.
 

Max22

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Jul 1, 2015
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Also not to mention the pre PI rods and pistons are stronger than the 99 and up ones because they went to crap pot metal for those engines to "save money"
 

Khenji Harris

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Nov 14, 2016
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Also not to mention the pre PI rods and pistons are stronger than the 99 and up ones because they went to crap pot metal for those engines to "save money"
Wow never knew that, so you said you are running yours without a tune? Has it been pretty reliable?
 

Max22

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Jul 1, 2015
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It was very reliable. I say was because I recently found a lot of metal shrapnel from some bearing in my oil pan and my engine is now toast. However I'd like to add that the previous owner was an absolute devil to that thing. How do I know? Just replaced my transmission and clutch 2 months back and I only have 87k miles.
 

squeak93

10 Year Member
Jun 2, 2005
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Do the full pi swap and don't look back. I tried to make power with stock npi heads and aftermarket cams. I now have fox lake heads, trick flow cams, 12psi procharger etc. I'm on a stock 58k mile npi short block. Looking for 400-425 when we re tune it. Only made 340 on npi heads. They are restrictive unported.
 

Khenji Harris

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Nov 14, 2016
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It was very reliable. I say was because I recently found a lot of metal shrapnel from some bearing in my oil pan and my engine is now toast. However I'd like to add that the previous owner was an absolute devil to that thing. How do I know? Just replaced my transmission and clutch 2 months back and I only have 87k miles.
Dang that sucks to hear, you just going to re build the motor?
 

Khenji Harris

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Nov 14, 2016
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Do the full pi swap and don't look back. I tried to make power with stock npi heads and aftermarket cams. I now have fox lake heads, trick flow cams, 12psi procharger etc. I'm on a stock 58k mile npi short block. Looking for 400-425 when we re tune it. Only made 340 on npi heads. They are restrictive unported.[/QUOTE
That's a big difference lol I know full pi swap is the answer but I was contemplating if just an aftermarket cam would be cheaper and easier. Honestly wasn't looking for a lot of power right now as it's my only car lol
 

squeak93

10 Year Member
Jun 2, 2005
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My Trick flow cam, pi intake, full bolt on (Npi headed) auto car ran [email protected] at 2500DA. While respectable for a auto car still not blazingly fast.

IF... IF you get cams, be sure to send them to MHS or a comparable shop to get degreed (Aftermarket cams that is). My cams were not degreed by the prior owner (that has since been rectified).
 

Khenji Harris

Member
Nov 14, 2016
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My Trick flow cam, pi intake, full bolt on (Npi headed) auto car ran [email protected] at 2500DA. While respectable for a auto car still not blazingly fast.

IF... IF you get cams, be sure to send them to MHS or a comparable shop to get degreed (Aftermarket cams that is). My cams were not degreed by the prior owner (that has since been rectified).
Oh so they don't come already in spec to be installed?
 

squeak93

10 Year Member
Jun 2, 2005
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Oh so they don't come already in spec to be installed?

You can install them and go "dot to dot".... But you'll be leaving a lot of performance on the table (some worse than others).

For example, my trick flow 1 cams were 6 degrees off from each other. One is advanced 4 and the other is retarded 2 after being degreed. You use adjustable crank gears to accomplish this correctly.

Mhs (sorry if I can't plug them) did the degreeing for me and even pinned the crank gears together so they don't fly apart at high rpms.