whats the diff between 90(375) &92(405)

[gmbrasco@aol.com]

hi guys, thank you for the previous support, im still considering the trade for the 90zr1. can anyone tell me what chevy did to bump up the hp, and can it be done on the 90. also what kind of mods can be done without affecting value, this 90z doesnt have orig wheels, has some mods.
also besides the front bumper, is there any other differences between 90-95, mechianicly. thanks agian

[Kevin]

The hp bump didn't come untill 93. Modifications to the cylinder heads and valvetrain; platinum-tipped spark plugs, and the exclusive use of synthetic oil were among the upgrades that brought this about. In addition, an electrical, linear exhaust gas recirculation system improved emissions control.

[Aurora40]

I don't think anyone can say what mods will/won't affect value. But if you are concerned, then anything you can undo should be ok (chip, exhaust, wheels).

The way I see it, there are plenty of totally original 1990 cars out there with like 7 miles on them. I can't compete with that, so why not have a lowish mileage car in tip-top shape that is modded cleanly to run the way they were made to run. Open up the in and out and let the motor sing, the 350 packages offered by various people/companies are really appealing to me.

Oh, also the 1993+ cars had a less restrictive exhaust system, I believe mainly centered around bigger resonator piping? The headers were different, though I don't know if they are actually considered better?

[Kevin]

I know I'm not concerned with keeping the car stock, but there are mods that you can do that no one will ever be able to check unless they take apart the top end of the motor and compare it to another, stock ZR-1. Port and polish the top end, chip. Toss in headers/exhaust you are looking at 400 to the wheels in a car that looks bone stock