First comment is that I do not think that it will be easy to make the 325 HP with a totally stock 3800 SC Series III. The standard engine uses a drive by wire and an auto transmission. You can convert to a cable operated throttle without a lot of effort and the engine directly mates to the Getrag 282 manual transmission with the correct thickness flywheel. There is some basis for my statement since I do own a 3800 SC Series III engine running in a Mera. My engine uses a VS cam, TOG headers, N* TV, Larger diameter air intake and exhaust tubing, 3.4" pulley, intercooler, ZZP fuel logs, and a relatively conservative tune pointed more toward reliability that absolute performance. The dyno on this engine indicated around 300 HP and 300 Ft Lbs of torque at the wheels when using a Getrag 282 transmission.

My current transmission makes use of a McLeod sintered iron clutch but I would recommend a SPEC Stage 3 Plus for performance and reliability. My ECU is a custom programed Series II ECU and I have oversized air intake and exhaust tubing.

The stock engine is supposed to produce 260 HP at the crank. With my setup I am fairly certain that I could get in excess of 325 HP at the wheels if I modified the tune, changed the cam, and used a 3.0" pulley. Since I drive the car a lot, I went for enhanced reliability instead of maximizing HP and I am quite happy with the final results.





Nelson

[This message has been edited by hnthomps (edited 07-15-2021).]

Can you make 325HP at the wheels? Its certainly possible but IMO finding the right combination of parts that will get you there is the key. Then you may want to consider gasoline mileage and reliability as well.
My preference is to run an early LS1 MAF, N* throttle body 3" exhaust and 11 psi of intercooled boost. Probably doesn't get to 300 HP but offers reliability and mileage. My setup is a series III run with series II powertrain management (2003 GTP PCM)


If I were to set out to make 325 HP it would be porting/polishing the heads, forged pistons, a race cam, everything that I have right now and a smaller supercharger pulley. ZZ Performance can give you the right formula.
As for your transmission choice; it is certain that your power goal far exceeds the design limits of the Getrag. It will not hold up pushing that type of power into it. I know three owners that fried their Getrag boxes with the 3800SC, two were stock engines. The F40 will most likely work.

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" THE BLACK PARALYZER" -87GT 3800SC Series III engine, custom ZZP /Frozen Boost Intercooler setup, 3.4" Pulley, Northstar TB, LS1 MAF, 3" Spintech/Hedman Exhaust, P-log Manifold, Autolite 104's, MSD wires, Custom CAI, 4T65eHD w. custom axles, Champion Radiator, S10 Brake Booster, HP Tuners VCM Suite.
"THE COLUSSUS"
87GT - ALL OUT 3.4L Turbocharged engine, Garrett Hybrid Turbo, MSD ign., modified TH125H
" ON THE LOOSE WITHOUT THE JUICE "

[This message has been edited by Dennis LaGrua (edited 07-16-2021).]

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" THE BLACK PARALYZER" -87GT 3800SC Series III engine, custom ZZP /Frozen Boost Intercooler setup, 3.4" Pulley, Northstar TB, LS1 MAF, 3" Spintech/Hedman Exhaust, P-log Manifold, Autolite 104's, MSD wires, Custom CAI, 4T65eHD w. custom axles, Champion Radiator, S10 Brake Booster, HP Tuners VCM Suite.
"THE COLUSSUS"
87GT - ALL OUT 3.4L Turbocharged engine, Garrett Hybrid Turbo, MSD ign., modified TH125H
" ON THE LOOSE WITHOUT THE JUICE "

[This message has been edited by VanGTP5000 (edited 07-28-2021).]