[65nss4spdGTO]

Originally Posted by PAUL K

It's not a great race head, in fact far from it. Also it's the only legal NHRA aftermarket Pontiac head.

Now we have "other" NHRA legal cylinder heads.

At least we can agree on your first statement.

Calvin Hill
Hill Performance
708-250-7420

[John Langer]

The classes where the 5 is legal, a Pontiac will not be competitive.

[Dragncar]

What kind of heads do they have to go up against. If its a class where the opponent can have the same CSA as the Pontiac RAV head, good luck.

[John Langer]

Splayed, canted, sbx, rox short deck etc. there is a lot more to it then just csa, the Pontiac has too much piston speed bearing speed, too long of a pushrod etc. many problems. That's why pontiacs get a weight break in heads up classes to be competitive. They get no weight break in a true pounds/cid class that has limited restrictions.

[Dragncar]

Thanks John, too much piston speed. So short deck, raised cam, smaller mains, bigger bores to even "think" about being competitive. Sounds like that to me.
What does the "rox" stand for ?

[AC445]

Ok,are the E cnc 0 ports with the heart chamber any better than the old chamber ?

[Stan Weiss]

Originally Posted by John Langer

Splayed, canted, sbx, rox short deck etc. there is a lot more to it then just csa, the Pontiac has too much piston speed bearing speed, too long of a pushrod etc. many problems. That's why pontiacs get a weight break in heads up classes to be competitive. They get no weight break in a true pounds/cid class that has limited restrictions.

John,
To me the problem is the need for a iron, low deck, small journal Pontiac block. The ROX is still only 4.5" BS. Your heads done flow as well as a done SBX?

Stan

[John Langer]

Originally Posted by Stan Weiss

John,
To me the problem is the need for a iron, low deck, small journal Pontiac block. The ROX is still only 4.5" BS. Your heads done flow as well as a done SBX?

Stan

They wouldn't flow as well on a 4.500 bore space block. I would have to dramatically reduce the intake valve size thus killing flow. You can package a what 2.25 intake and 1.600 exhaust valve in a 4.500 block? If I kept my valve and bore diameters and dramatically reduce the stroke to achieve around 400" with a short deck block, I'm still not sure how you could package the rotating assembly inside of the block.

[Stan Weiss]

Originally Posted by John Langer

They wouldn't flow as well on a 4.500 bore space block. I would have to dramatically reduce the intake valve size thus killing flow. You can package a what 2.25 intake and 1.600 exhaust valve in a 4.500 block? If I kept my valve and bore diameters and dramatically reduce the stroke to achieve around 400" with a short deck block, I'm still not sure how you could package the rotating assembly inside of the block.

John,
That is how I was looking at it. I do not know your bore size.

ci = 399.839
bore = 4.35"
stroke = 3.363"
rod = 6.2" - I know this is long
compression height 1.2"
block deck height = 9.0815" - The question is how low a deck height can be made.

How would the valve train dynamics of your heads be @ 10500 RPM?

Stan

[Tom Vaught]

Fords were in the 8.2" deck height range for years and could not make any power until they added a boosting device. They they did a lot better. Lots of 9500 rpm SB Fords out there.

Pontiacs would not be competitive, as John L posted, for the most part, same as a 8.2 deck height Ford would not be.

Tom V.

[Stan Weiss]

Originally Posted by Tom Vaught

Fords were in the 8.2" deck height range for years and could not make any power until they added a boosting device. They they did a lot better. Lots of 9500 rpm SB Fords out there.

Pontiacs would not be competitive, as John L posted, for the most part, same as a 8.2 deck height Ford would not be.

Tom V.

Please explain to me why would a low deck Pontiac would not make any power N/A? I believe a well built 400 ci low deck Pontiac could make very good HP per ci numbers N/A.

Stan

[John Langer]

Originally Posted by Stan Weiss

John,
That is how I was looking at it. I do not know your bore size.

ci = 399.839
bore = 4.35"
stroke = 3.363"
rod = 6.2" - I know this is long
compression height 1.2"
block deck height = 9.0815" - The question is how low a deck height can be made.

How would the valve train dynamics of your heads be @ 10500 RPM?

Stan

I have steel jesel rockers similar to what pro stock uses. 10.5 wouldn't be the issue.

[dci]

I personally think the only limitations we have are the ones we impose on ourselves. Other brands and makes don't do this and look where they are. I will tell everyone here like I tell my own children. I do not like the word Can't or cannot. If everyone believed that, we wouldn't even have running water in our houses. We wouldn't be able to travel in space. For that matter we wouldn't even be able to communicate like we are right now. Can't is a very powerful word and has destroyed many good men and women.

[tooski]

Originally Posted by JSPONT

Paul Carter did a nice thread on an IA block someone bought and all the stuff he had to do to get it correct.
I am not bashing trust me, but as a guy a a very tight budget, if I knew the block just needed a piston bore to what I wanted, I would go for it. But needed line bore, cap work, deck work, not sure if they fixed it but oil galley work.
I am just saying I think more might buy it then.
I can not tell you my source, but he has looked at many blocks not 1 was a bore and go. They all need work from what I am told.
Please don't take this as anything but constructive critisizm

I know my comment is a bit late on this aspect of this thread, but I just came across this thread.
I am fairly certain I read (if it is the same) Paul's thread on his machining of an IA block that needed much work. It was pointed out that the block was nearly destroyed by the poor workmanship of the original builder, not a new casting.

[Dragncar]

From what I understand the latest IA blocks the main and cam bores are good to go. Maybe someone who knows more can chine in. I believe the Boss Bird folks had their last block and it was good to go there.

[BruceWilkie]

I think whether it's an IA block or MR1. (Iron or aluminum)You buy the block that meets your application.

In fact have it finished to whatever rotating assembly you plan on using.

Choosing your builder or machinist is an important decision.
Avoid shops that employ "Monkees".

(Deb's cousin is a good machinist, but he got very little work from me back in the day, unless he personally did it and kept it away from his "monkeys"! We no longer live close enough that I'd bother to use him for anything.)

[BruceWilkie]

I do have Butler @60 miles off.my backyard if I decide to use his services.