To all us Olds lovers in the world PLEASE don't put a smallblock Chevy in it.

I helped a buddy swap a 455 into this exact car about 6 years ago, and it worked out ok, but 394's are plentiful, and will bolt right back in.

I understand your motivation, but for the work you go through putting anything in it just to get it going, but if you are doing all that, put an Olds back in it so the engine looks sized right for that massive engine room. Plus, you need torque to move that thing.

JMO, Don