"Tight" is an understatement, but it can be done. Lots easier to install the headers while the engine is going into the car than to try to get them on with the engine bolted in place. Ground clearance is another issue. I'd go with FPA tri-Y headers for ground clearance reasons. Test fit them with the engine and trans hooked together in case you need to grind anything (a block boss, transmission case, etc.) to make them fit, and then install them with the engine/trans. Usually I can get those installed with the driver's side header bolted on from the start, and then after the engine and trans are in position but still up off the mounts by 6" or so, bolt the passenger side on, then drop the engine down onto its final position.
