Yes it's mod dependant. Trying to make everyone happy, I'm doing some options now so there's a bigger range to cover. I'll try and explain: For pulley sizes 3.0 to 3.4 the standard porting works the best as long as supporting mods for these pulleys are utilized. These are done differently than previous versions I've done. The bore on both the '97/98 and 99+ TB has been increased to 72mm. The hump is taken down 5/16" and the maf is sleeved and raised 1/4". That area is reshaped to form a d-port to increase velocity. No external adjustment device for the TB is neccessary, but is reccomended. The '97/'98 TB does not include a hump, so a section of the post is removed. Out of these two, both work well, but the '99+ has a flow advantage.
For cams and pulley sizes smaller that 3.0, I can modify a '97/'98 style TB to use an external MAF. The normal maf post is removed and filled, the bore is increased to 75mm, and the shaft is thinned. This will allow comperable or better flow than the LS1 TB, and should cost under $450 for the entire kit. An external adjustment device is required to use it. However, with the IAT built into the external 85mm MAF, it will include a pigtail to connect to it, and the stock IAT will not be required. The kit will contain the TB, MAF, MAF recalibrator, gasket, silicone coupler for the MAF to the TB, Drill bit and plugs for the SC coolant holes. A tap will be required to thread the SC coolant holes.
I'll have more detailed info soon, and some pricing, but this is the jist of it.
Ron