I guess I should respond to this since Jim used my name in vain? about my Willit? project. Yes indeed, the GM 60 degree V-6 will fit in a GT with some mods to the driver's side footwell and the wiper well. You will also have to custom build an engine crossmember and tranny mount, and find a different gas pedal setup, I'm still working on that one. Oh yeah, and build custom exhaust manifolds, alternator brackets, shorten the driveshaft if you go with a T-5 tranny, and get a cable X box to drive the speedo, along with a whole bunch of bits and pieces to put it all together. For sure you'll need the DESTEC wiring schematic for the GT and all the manuals you can find for the engine your putting in, especially for the wiring harnesses for the engine computer so you can integrate the engine to the GT. If you try to put in a coil, distributor/carbed engine, you're in for a bigger hassle, because the distributor is going to be up against the firewall. You can use the GT radiator, but it needs to be recored to a 3-row and you'll need a 14" Perma-Cool high performance radiator cooling fan. I could go on and on, but yes the GM 60 degree V-6 will fit, nicely, if it's the right one. HTH.