I undestand , and agree. We all do these things the way we feel comfortable. Just wanted to save you some money on a swap.
There's only one real problem with offsetting the engine, (beyond the time and money we've already discussed) and that's the hood. The aftermarket cowl induction steel hoods have a round hole on the inside to match up with the air cleaner. If you use the BBC frame and engine mounts you'll be stuck using the special low profile intake mainfold that came on BB Camaros. Anything else will be higher and need to fit in that round hole, but it wont if it's offset. The hole is only 15" in diameter, so any movement will create clearance issues with a cowl hood.
Couple other options would be to get a fiberglass hood, or cut a hole in a stock hood and install a custom hood scoop.
I ran into this with mine because of the intake being much higher than stock. I had a Corvette style L88 hood glassed to my stock hood and it cleared everything fine, but I wanted a steel cowl hood. Now my 14" air cleaner doesn't fit, and I have to run the 14" dropped base, with a 11" element and lid to get it to fit. It's only got 1/4" clearance on the top, but it's working for now. I still plan on doing something different, but it will probably mean I'll fabricate my own base to drop the element even further and get it so it clears.

 

Correct! Fortunately for me I'll not have to hack up my Z hood. I just happen to have a pristine stock hood in the back just waiting for me to hack-n-install. I'm thinking tall tunnel rams! Not really but I'm thinking an aftermarket cowl induction scoop to put on the hacked hood. If my dreams come true and I win the lottery I'm putting dual quads on it.

 

Oh yeah! I got 'em!