[67'7F6'Bird]

Are there any concerns with putting Iron Round Ports, maybe my 7F6's 111cc chamber on an IA2 block other than the Intake/exhaust Flow feeding the larger cubic inches compared to my 462?

[bankbook]

Originally Posted by 67'7F6'Bird

Are there any concerns with putting Iron Round Ports, maybe my 7F6's 111cc chamber on an IA2 block other than the Intake/exhaust Flow feeding the larger cubic inches compared to my 462?

I would call Jim butler and ask, The advice is free.

[pro-tour79]

why would there be any concernes?

[67'7F6'Bird]

Originally Posted by pro-tour79

why would there be any concernes?

I was thinking probably none. I would upgrade in the future to higher flowing Aluminum heads.


How would this motor react lets say 505 or 541 with these heads?

Has anyone tried any iron heads on an IA2?

[Brian Baker]

Any factory head will work fine on the IA-2 block, and if running a larger than factory bore it will allow the head to flow better than it would on a factory sized bore.

[67'7F6'Bird]

Originally Posted by Brian Baker

Any factory head will work fine on the IA-2 block, and if running a larger than factory bore it will allow the head to flow better than it would on a factory sized bore.

Any idea on what the flow increase may be going from a 4.18 bore to a 4.25 bore or larger?

Would the increase be marginal?

[67 Lamnas]

If it were me in your shoes, I'd go for a 535 (4.35 X 4.5), and upgrade to better heads later.....your 7F6's should put you around 9.5-9.8 SCR ........

[Probird]

You can also get the IA2 in a smaller bore size. I think they can go down to 4.12.

[67'7F6'Bird]

Originally Posted by 67 Lamnas

If it were me in your shoes, I'd go for a 535 (4.35 X 4.5), and upgrade to better heads later.....your 7F6's should put you around 9.5-9.8 SCR ........

If the old 462 had 550 HP what do you think the extra 70 cubes would bring, everything else the same for now?

[WARPed]

Originally Posted by 67'7F6'Bird

If the old 462 had 550 HP what do you think the extra 70 cubes would bring, everything else the same for now?

There would be a mild increase in HP but the torque will go way up and all of this would happen at lower rpm's.

[Brian Baker]

Originally Posted by 67'7F6'Bird

Any idea on what the flow increase may be going from a 4.18 bore to a 4.25 bore or larger?

Would the increase be marginal?

Not a clue...all I know is there would be less valve shrouding, and thus, more available flow. For years 4.25" has been the industry standard when flowing heads for comparison, but with larger bores being used who knows what published flow figures are achieved at anymore.

[Robert C.]

You will be fine with any head that is a Pontiac head.


Most people are building a 4.350 bore block. Remember to get the pistons that have the 12 deg. valve angle. With that done you can use any head later on Tiger, E-head, KRE High Port. KRE D port, Wensler, Stock D port, except the CV1. You can up grade as you find the funds with out change the bottom end. We can sell you the rotating package 4 1/2 forged crank, rods and pistons too.

Better yet call AllPontiac for a short block assembly price. We have a 505 IA II CI short block assembly in stock.

With the combo that you ask about, you will have a torque monster at 3500 rpm.

[PONTIAC DUDE]

I supply BRC pistons with both straight and canted valve pockets in the same piston. Good price too.

[Mr. P-Body]

There may be a slight problem if you're using cast iron exhaust manifolds. There's a large "overhang" (about 1") on the deck surface at the exhaust side of the head.

We've flowed heads with both a 4.185" bore and a 4.350" bore. Typically, one will pick up and 6-8% on the INTAKE side. No appreciable difference on the exhaust side. In one case, E-heads went 320 on the 4.185 bore and JUMPED to 355 on the 4.350 with NO changes to the head. In most cases, simliar, but not quite as "dramatic", gains were made.

Jim

[67'7F6'Bird]

Originally Posted by Mr. P-Body

There may be a slight problem if you're using cast iron exhaust manifolds. There's a large "overhang" (about 1") on the deck surface at the exhaust side of the head.

We've flowed heads with both a 4.185" bore and a 4.350" bore. Typically, one will pick up and 6-8% on the INTAKE side. No appreciable difference on the exhaust side. In one case, E-heads went 320 on the 4.185 bore and JUMPED to 355 on the 4.350 with NO changes to the head. In most cases, simliar, but not quite as "dramatic", gains were made.

Jim

Hello Jim,

Thats good information on the flow.

I have 2 different sets of 2" primary tube Headers I can use, Hedman Hustlers or Indian Adventures for my 1s gen Firebird.

Steve

[67'7F6'Bird]

Originally Posted by 67 Lamnas

If it were me in your shoes, I'd go for a 535 (4.35 X 4.5), and upgrade to better heads later.....your 7F6's should put you around 9.5-9.8 SCR ........

I was using this compression calculator,

http://www.race-cars.net/calculators...alculator.html

and your right, if I went normally aspirated I'd go with the 535 if I had no intentions to boost and would only look to upgrade the heads in the future.

My other choice done in the following stages(when $$$ permits) looks good too:

Step 1 (499-505 lower end with my 111cc Round Ports and dished pistons.)

Step 2 (New Higher flowing Aluminum heads)

Step 3 (Finally add a centrifigul Supercharger)

Step 4 (scare anyone who drives with me)

Regarding the dished pistons, what is the safest maximum dish possible?

Steve