[mgarblik]

Not that familiar with these heads. Waiting for bare castings and want to get some other parts ordered/worked out. 1 . What is the actual overall length of the intake and exhaust valve ? 2. What is the typical installed spring height most of you are using? Thanks.

[JD]

I ran a set of 72cc heads for about 10 years and the valve length I had was 6.200" overall length and the spring installed height ranged between 2.000" to 2.100" depending on what spring I used. I ran Manley 221424 & 221425 springs with a roller cam.

Before I sold the heads I had the chambers enlarged by KRE to 85cc and that moved the valve deeper into the pocket, which changed the spring installed height.

[Steve C.]

Mirrors the above info....

http://www.tinindianperformance.com/...cylinder-head/

Two other spring choices to consider are the Comp 959 and the Comp 991


.

[Steve C.]

Valves to consider:

F1250P
F1251P

https://www.ferrea.com/pontiac-compe...ne-valves/p534

On my HP castings we used 2.230 titanium intake valves and 1.700 stainless valves, both 6.250" in length.
The springs were Manley 221448 at about 2.100" installed height used in conjunction with a 50mm custom Bullet Racing Cams solid roller with 0.850" / 0.817" gross lift.


.

[mgarblik]

Thanks for the input so far. This customer build is a a little more mild. Solid flat tappet cam. So I need to get the installed height way down to around 1.800-1.850 with the deep 85CC chambers. Spring choices are a bit tricky getting something soft enough on the seat yet about .060 from coil bind at full open lift. Going to be run at sustained high RPM's for 1/2 hour at a time. 6500-7000 RPM.

[Skip Fix]

Going to be run at sustained high RPM's for 1/2 hour at a time. 6500-7000 RPM.


Boat?

[mgarblik]

Road race car. Up and down, torque zone to HP zone. Hasn't been on dyno yet. Anticipate peak torque 5200-5700.

[steve25]

My experience with the 72 CC head is like reply post number 2 also.

[Skip Fix]

Cool! As heavy as the High Ports are vs an Edelbrock head ( I have a set I know) and it's shorter valve I almost wonder if some max Eddy heads would work better-tossed on top of an aluminum block!.

[Elarson]

Originally Posted by Skip Fix

Cool! As heavy as the High Ports are vs an Edelbrock head ( I have a set I know) and it's shorter valve I almost wonder if some max Eddy heads would work better-tossed on top of an aluminum block!.

The hi-ports have the advantage of flowing well in as-cast condition so there will be no thin walls from a max effort porting job. Aluminum IA2 block is part of the approach. Rugged simplicity (with major weight savings over an all-iron engine) is the plan.

Eric

[Steve C.]

The website touting "As cast heads flow around 330 cfm on the intake" is based on the large diameter 2.200" valve, that and rated at 0.700" valve lift.

Curious, are you going to retain that size intake valve ? And what is the intended valve lift with the solid flat tappet cam ?

.

[steve25]

Sounds like oil cooler time also!

[Elarson]

.584" net lift
And yes, an oil cooler is already in hand.

Eric

[Skip Fix]

Cool deal! I started out autocrossing and even a track day with my 78 TA so I like going around corners. Even picked up a Late Model that got the rear fuel cell area banged to make a cheap road race car-dry sump, dual MSD systems, quick change, fire system, healthy 350 180 degree headers. Just too many projects but hey It's a third gen Camaro you could reskin a Firebird and I'll make you a deal on it!

[Elarson]

A quick summmary:
'75 Firebird
All- aluminum real Pontiac
The biggest brakes Wilwood makes
Lots of Herb Adam's influence in the suspension
18" replica Minilites for the right vintage look

Eric

[Skip Fix]

Got a set of Herb Adams weld in control arms bushings never used if you want more of his stuff! Lowers use a spherical Uppers steel with a Nyliner insert. I copied the outers in a press in on my 78 TA.

[Elarson]

I got some guidance on valves from Jeff today.
This engine will have parts from all the Pontiac sources: AllPontiac, Butler, KRE, Bullet, Crower, Hedman, Summit. We are genuinely fortunate to have so much aftermarket support.

Eric

[Skip Fix]

They guy I got my High Ports from had a set of Comp 943 springs for them but I have the Manleys I plan to use 1.9 IH. Got the Comps new in box still.

[Tom Vaught]

Originally Posted by Elarson

I got some guidance on valves from Jeff today.
This engine will have parts from all the Pontiac sources: AllPontiac, Butler, KRE, Bullet, Crower, Hedman, Summit. We are genuinely fortunate to have so much aftermarket support.

Eric

Is the vehicle going to have a wet sump system or a dry sump system?
Tom V.

[mgarblik]

I can answer for Eric. Wet sump. Melling M54F pump. Canton steel road race pan, oil cooler and accumulator. That's it. Nothing exotic. This is a have some fun on the weekend deal. Nothing like the last two projects. Still plan to have some fun supporting the effort a little.