Truck bells are slightly deeper too. Will cause input failure.
Early bells (5 bolt type) won't work for you either.
You have 3 choices:
1) Lakewood steel bellhousing. Expensive new, cheap used. Will readily accept 10.5" clutch and flywheel. The 11" can be made to work, but it is very tight.
2) The 10.5" 289-302 bell. It is aluminum and uses the smaller clutch/flywheel.
3) The 11" 302 Boss/351c/w bell. It is iron. Strong, but heavy. It uses the larger clutch/flywheel for better power transfer. It works very well on a 289-302 and is all I have used due to more clamping area. The truck 11" is just like this, but is .250 deeper.
I have 2 11" bells, and 1 10.5" bell laying around. One 11" is off a 70 Stang. Boss 302 from what the numbers on the tranny said.
I am in Pensacola FL.
I am not game for shipping the thing, but would do a local sale.
Dave