Swapping 454 into '70 GMC 3/4 ton

[tommckean001]

Hi Folks. I'm new to the forum and hope you guys can help me with my current project. The 350 in my '70 GMC finally died and I found 50,000 mile 454 from an '89 fleetwood motor home. The block # is 14015445. The heads are 14092360 oval port. A friend and I will be doing the work. I'm not a "big block" guy and so far I have the heads and oil pan off, and everything looks good. My current plan is to use the rotating assembly and add as follows:

1) Heads: 300 cc aluminum oval ports, 116 ? combustion chambers Procomp.
2) appropriate "street" roller cam with misc. appropriate hardware (pushrods, studs, guides, alum. roller rockers, etc.).
3) dual plane aluminum intake with 850? holley or edelbrock carb.

I have (so far) the following questions (I'm sure they are all answered somewhere, but all I'm getting is confused):
1) Please comment on the proposed setup - all advise appreciated.
2) If I go this route, I'll require tall valve covers. Will they fit?
3) Will a HEI distributor fit? I'm trying to avoid messing up the firewall.
4) I have the original small block motor mount cradles, and both the small block and big block mounts. Will some combination of these fit?
5) Can you tell me if this is a tall or short deck?

Thanx in advance. Tom. I'll add to this and respond as appropriate.