Your profile info indicates your V6 has a "6 speed manual". Since the T56 was not available with the V6, appears you have already done a transmission transplant. If that is correct, do you have the LT1 version of the T 56, or the LS1 version? McLeod makes a universal, modular, explosion-proof bell housing that connects the LS1 version to virtually any engine.this is probably the dumbest thing you've ever heard of but here goes. So I have a Ford van sitting in my garage and I got this dumb idea of swapping out my 3.4sfi v6 for a 5.4l triton v8. So now I'm trying to figure out if I'm gonna have to swap the transmission in my firebird or it if it'll work in the new engine, if not what would I need to make it work?
On the other hand, if your V6 actually has a T5 5-speed manual, which is the only manual available with the V6, it's most likely too weak to stand up to a truck engine that produced torque rather than HP. You would be looking at a Tremec TKO 500 that could stand up to the torque. Those are available for Ford engines.
Personally, based on 150,000 miles on a Ford F-150 with the Triton engine (company supplied truck), it has issues of its own, the major problem being the spark plugs with the ridiculously long nose required to reach through the bulky head. Typically, the nose breaks off when you try to unscrew the plug since the annulus between the head and the plug nose is packed with compressed carbon. That engine is also very wide, due to the OH cam heads. Simply measuring the width of the Triton engine should enable you to determine if it would even fit in the F-Body's narrow engine bay.