[oldskool]

"...My thought is that a mid seventies 455 would be a good choice when compared to similar year 400 motors..."


That's an interesting thought. I have eliminated all round port iron head engines, due to availability & cost. So, that leaves the '73-'74 D-port 455, as probably the best choice. Rated @ 310hp in GT/Auto.

They've been proven good in 10 sec Stockers. But right now, I can't think of a current car running one, in SS. Should easily run the index in a car that can hook it up. Now, as to how much power one can make, in SS form, I don't know.

When comparing them to 400's, I'd say they are a better choice over the '74 & '77-'78 400's, which are rated @ 290hp. Advantage of those '77-'78 400's is the common 6X head. Cores should be cheaper than any of the other good Pontiac heads.

Wilbert Thornton runs a '74 400 SS Bird. Jack Good now owns the '78 400 SS Bird that Ken Shawver once owned. The '74 & '77-'78 400's have been used by several GT racers.

The lowest rating for one of the early high compression 400's looks to be a '69 350hp GTO engine. It shows the same 310hp as the 455 we're talkin about. At the same hp rating, I'll choose the extra torque of the lower compression 455. Will require less rpm.

Art Peterson has the only '69 GTO SS car I know of running the '69 D-port 400 engine. Don't think it's an all-out car. Nice paint, but older technology. Roy, Mike, & Marty McKinney have ran a similar engine in their '68 Bird, for many years.