"...would like to know I could get my money back if I sold it after a rebuild...
You can NEVER plan to recoup ALL your money from a Pontiac build. The price you get will strictly depend on where you live & whether there is a Pontiac guy near you who needs exactly what you have. Because so many sellers lie, in order to sell what they have, most potential buyers will assume something is wrong with a recently rebuilt, but slightly used engine.
I had a nice 455 bracket engine. It ran high 11's in the 1/4 mile, & 7.30's in the 1/8 mile, in a '74 Ventura. Had forged pistons & rods & a decent HFT cam, #215
heads, a deep oil pan, a Torker 2 intake & 750 vac Holley. Track closed, so I sold the Vent as a roller. Tried to sell the engine, for quite a while. Was only trying to get $3k. Would cost more than that just to build the shortblock.
Didn't even get an offer for a long time. I finally had to come down to $1000 to sell it. And a guy came down from IL to buy it. Only reason I sold it that cheap was because I had another good 455, and I really needed some cash, at the time.
If I HAD to build a Pontiac engine, hoping to recoup most of what it cost me, I'd go with a 481988 400 block, because it's a popular block, & will fit both the '70's models, & the '60's A-bodies & Birds, as well as other bodies. I'd probably use 6x-4 heads. 2nd choice would be 5C-4. 3rd choice would be late '73 or '74 #46
heads, with screw-in rocker studs. And I'd use either a '72 iron intake, or a Performer, and a good Q-jet carb. Well, you get the idea. I'd build something that would work well in a large variety of street Pontiacs. A 389, with 389 heads, water pump & pulleys, just won't work in a large percentage of Pontiacs still on the street.