The relocation plate Jerry speaks of is made by member Pre68Dave here on this site. It is an easy mod requiring 2 drilled and tapped holes in the block, then use your rebuilt 216/235 waterpump.
I have a 57 235 in my 54 3100 using Dave's plate and have 4000 trouble-free miles on it.
Everything that bolts to the front or rear of a 216/235/261 is interchangeable. Use your current bellhousing, flywheel etc and your current harmonic balancer.
55.2 and up are 12v and use a different flywheel than your 6v 54.1 truck. The tooth count and angle of the starter gearing are different. Should you decide to convert to 12v at a later date the 6v starter does just fine on 12v.
Have fun... I did!
