BUILD OR BUY

You will apprecaite the car alot more if you just build this one. Selling your's and buying one already build should never be an option. 99% of the time, you do not know the person selling the car. So you dont know how the car's been treated and if the motor it REALLY built like they say it is, ect ect.

Anyways, my vote would be to ditch the supercharger all together and go turbo. You can make more power with a turbo set up

So you currently have 11psi, and no intercooler on PI heads with a NPI bottom end? It must be tuned for like, 4 degrees of total timing under boost to control detonation!! Your EGT's must be insane, and your leaving a lot on the table.

Well, I recommend E85, no matter what combination you choose. You can make stupid power easily with E85. It has the octane of race gas, but is cheaper than 87 octane. It will be a huge help to get the power numbers you are looking for, and E85 will give you a much nicer mid range than would ever be possible on a gasoline combination. To tell you how much fun E85 is, imagine 22psi on 10:1 compression with an aggressive amount of timing advance. That's what I'm running on my 2.3.

Anyway, build what you have already. I personally recommend E85, lots of boost, a build bottom end with around 10:1 to 11:1 compression and a big front mount intercooler... all to match your big cams and current blower. The higher compression and better fuel will make more power with less airflow, allowing you to use your current blower and make more power. If you are sticking with pump gas, you can probably still keep 8.8-9.0 compression with a centrifugal blower.

You have tons of great mods which will help if and when you change things around. If you are looking for 600 hp you already have a great base in your 98 GT.

Engine: You can keep the block, upgrade the crank, rods and pistons - while at the same time get the piston size you want for the compression you want. Something in the 9:1 range is usually good for 93 octane + boost on a good tune. While you are working with the block it would be a great time to look at porting the PI heads or taking a look at some trickflow heads. Keep your 270 cams, they will work nicely and give you some great upper end power. Then to top it off, sell the powerdyne and use the money to buy a 2.1L intercooled kenne bell and you should be able to crank it up to your goal. Or you could buy a vortech t-trim (intercooled also) and hit your goal that way too.

Tranny: At a minimum I would get a stronger clutch and resurface/ get a new flywheel. If you go to the track much and start making some hard launches at such power levels I'm not sure how long the stock tranny is going to last.

All in all you are looking at several thousand in parts but 600 is defiantly do-able.

Keep in mind u will also need more fuel system upgrades, maf, 60# injectors, drivetrain mods and suspension to keep the car planted. I would get rid of the powerdyne and go with a twinscrew or better centrifugal blower. To keep with pump gas at that level u will most likely need better flowing heads. E85 is a nice option but check your area for availibility to make sure ur not stuck with one gas station offering it.