Pontiacs

[john corcoran jr]

The only reason I ever thought of doing a late model GTO was a visit to my favorite chassis shop and he was parting one out. He used the eng/trans for a customer car and wanted the rear end for one of his projects. He told me it would be about 20k to convert to SS with 8.50 cage, 4 link, rear end, and fuel cell. I didn't go ahead on the project because I thought I should finish off another project instead. He still has the car but it needs more parts now. Needs front fascia, grille, one fender, rear fascia and rh quarter panel repair if anyone is interested.
Remember that when building a Pontiac motor, it will cost you the same regardless of engine size. My thought is that a mid seventies 455 would be a good choice when compared to similar year 400 motors. Yes I know the 428 with the Edelbrock heads has an even better hp rating but when did you last see a set of those heads for sale?

[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.

[Stan Weiss]

Originally Posted by 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. 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.

At most Nation events how far under their Index does one have to run to qualify?


Stan

[Billy Nees]

Originally Posted by Stan Weiss

At most Nation events how far under their Index does one have to run to qualify?


Stan

At MOST Natl. Events? You don't.

[oldskool]

Originally Posted by Billy Nees

At MOST Natl. Events? You don't.

At Indy this year, the bump spot was only .536 under, in Stock, & only .350 under, in SS.

https://www.dragracecentral.com/DRCS...r2021#indextop

https://www.dragracecentral.com/DRCS...r2021#indextop

It has been said that many of the quicker cars did not go to Indy, for a variety of reasons.

I think there have been some years when you had to be nearly .900 under to make the 128 car field. I'll find one of those & post a link to it.

The Stock bump spot was .893 under, in '16 & '17.

https://www.dragracecentral.com/DRCS...r2016#indextop

https://www.dragracecentral.com/DRCS...r2017#indextop

The '19 SS bump was .783 under.

https://www.dragracecentral.com/DRCS...r2019#indextop

As Billy said, at MOST nat events, all cars that pass tech can run, no matter how slow.

That's how some really slow cars have won big races. They just didn't have a same-class heads-up round.

So, if you're trying to do some class racing on a small budget, you might wanna choose a class that does not usually have very many entrants, especially not any quick ones.

Sometimes you may be able to change classes up or down 1, by adding or removing weight, depending on car & class. This might help avoid a heads-up race with a quicker car, at a particular race.

[Billy Nees]

Originally Posted by oldskool

" Advantage of those '77-'78 400's is the common 6X head.

THAT isn't the only advantage of the 6X head on the 400.....They have a very (very very) benevolent combustion chamber spec. ;-)