Out with the old, in with the new. Jay Leno swaps ZF trans for Tremec TKX 5 speed at 4:42 into the video.
I have a Tremec 5 speed in a 1952 Jaguar XK120 roadster and it completely transformed the car. I love how that car shifts. Granted the 4 speed Moss box, without first gear synchronization, originally in the XK120 is archaic compared to the ZF 5 speed found on the 3500GT. Still, this 3500 GTi should shift very nicely with its new gearbox. Ivan
T-5? The TKX is a brand new design for more torque and hp. Mostly targeted to the muscle car resto mods.
Do you want to look at cars or drive them. If it is the former and the car doesn't drive well from the factory then park it and admire it. If, on the other hand, some minor modifications will make the car enjoyable and make you want to drive it, then do so. If you make changes but want to make it possible to return to the original build, then save the parts and document the changes so that some future owner can reverse the process if they chose.
I wouldn't call this a minor modification and if you're not Jay Leno I think it's probably a very expensive proposition to get it done well. He has a tremendous amount resources to ensure that it does and I don't just mean money. His shop is amazing. Also, a 3500 isn't a very rare car. Were their transmissions really that big of a problem?
Changing out a transmission that is hidden from ordinary view is not a major upgrade when you consider the value of a good driving 3500. Granted making the new bell housing and having a new prop shaft made isn't cheap but given the value of the car they are perfectly acceptable as expenses if you aim is to enjoy the car through regular driving. If you don't plan to drive the car very often then leave it as it is but otherwise upgrades such as Jay Leno made are fine. Mind you, Jay Leno has so many cars that his collection is the exception to the rule of frequent verses infrequent driving but for most people who don't have such a large collections and have far fewer cars or even one which they like to drive as much as they can, why not make the experience as pleasant as possible but for future owners make sure you save the old parts and document the changes so that the car can go through a restoration to original configuration.
