[Hanzel]

Hey experts, Which are the best fitting heads for replacing on a ('66) 326, 2brl, 094, 0.40 overbore, w/o clearance issue's? Or leave with original one?
Rebuilding is problably a bit expensive, so i looking if there are any other options. (Driving octane 108, so hardened valve's probably needed..)

[Ed Fitzgerald]

Put a set of 2.02 (chevy) intake valves in it and some hardened exhaust seats. Would run better than 326 with HO heads and with a decent cam ( 212/212 @ .050 and 440 lift) could approach 300 hp and over 350 tq. Ed

[John Eiseman]

Hanz is running propane to get the 108 octane and can switch over to , 95 octane gas when desired.
Hanz, will you be running anything less than 95 octane fuel? What is the lowest octane available to you there?

[Hanzel]

95 is the lowest here, but drive mostly on propane ( normal driving)

[steve25]

X2 with Ed kind of , but to use the 2.02" as is means using its low lift flow reducing 45 degree seat, you would be better off taking new 2.11" valves and bringing them down to 1.98" to 2.00" with a 30 degree seat as stock.
On the Exh side these 326,389,421 type heads need work, as in bowl porting them.
When the needed seats are installed they need to be hand blended in anyway so your already doing work to them.
The other thing to check out before hand is that once the hard seat is blended in that you end up with the same valve bowl throat area that you had before, if not then you will have reduced the peak flow that the Exh once had!

This issue is a very good reason to step up to a bigger Exh valve so that the before mentioned throat to valve percentage atleast says the same or maybe even picks up some!

I know this all cost money, but a motor is nothing more than a air pump and to this end your always better off with better flowing heads than more Cam when it come to a true street car!

[ID67goat]

Originally Posted by Hanzel

95 is the lowest here, but drive mostly on propane ( normal driving)

Just an FYI...The octane calculations between the US and Europe are different. What is called 95 octane in Europe would probably be the equivalent to 89-91 octane in the US.....so basically the same gas.

Adding propane is a whole other variable that I have no experience with, but the chart I just looked at said the EU octane rating is 112 which would be 105 in the US.

[steve25]

Also with any Cam above .420" lift the press in studs will need to swapped for screw in and guide plates along with different lenght push rods to get ther geometry back in place when longer valves are used will be needed.

[Ed Fitzgerald]

X2 with Steve. Let me clarify my shop guy put 2.02 chevy valves and cut them to 30* with the seats. We used a CC 260H-10 cam and it produced 298Hp and 350ish tq from what I remember. (maybe even a little better) but down want to argue with anyone. Ed

[Hanzel]

To be honest there is not so much knowledge over here with pontiac heads about adjusting and blending. Also parts are quite rare here so need 100% sure if i import stuff to here. So is there a best choice without much of blending..? Or are all need heads different then 094, need some work?

[gtofreek]

When I install 1.94" and 1.625" Chevy valves in these heads, there is only about .037" between the valves, so I'm not sure how a 2.02" valve will fit while still maintaining at least the stock 1.600" exhaust valve. Definitely cut them to 30° if you go with the Chevy valve.

Are you near Sweden? If so, I can hook you up with a guy there that knows Pontiac heads. His name is Peter, with PPM racing.

[Hanzel]

Sorry, sweden is too far ( def planned to go the "big meet" in sweden, though)..

[72blackbird]

I built a 326 for a customer who wanted to use what he had, but still wanted much more power than stock. We ended up going with custom heads from KRE. They set the heads up for a 56cc chamber, 2.05/1.66 valves and springs for a HFT. Bottom end consisted of stock pistons on 4340 H-beams, stock crank- rotating assembly balanced and oil clearances set at .002". Cam was a Comp cams XE 268H- induction is a 780 cfm vac.sec.on a port matched Performer intake. The owner reports it runs more like a well built 400, and has trouble convincing people it's only a 326. And taking a ride in his 67 Firebird, I'd put output easily at around 375-400 hp.

Geno

[steve25]

Just note that if you use any type of later head be it stock ( with one exception) iron or aftermarket Aluminum you can not run more than .420" to .440" valve lift due to the change in the valve inclination angle !
The 1967 2 bbl 400 head is still a 389/421 style head and will work with the valve notches in those Pistons.

[gtofreek]

Not to mention the small bore size of the 326. The big valves heads will hit with enough lift.

[John Eiseman]

So , would a set 67 cast # 143 heads be that much of an improvement over Hanz ' stock heads with the 326?

[GRX]

Originally Posted by John Eiseman

So , would a set 67 cast # 143 heads be that much of an improvement over Hanz ' stock heads with the 326?

My mind says - no. The #143 still have the older valve angle and same size valves as the #94.

[steve25]

The only difference would be which head in a minor way flowed better or worse due to casting / core shift differences and or how they where rebuilt!

[Hanzel]

Thank you all,
I'm looking at KRE, seems interesting. What info is necessary for KRE for a good offer, i mean, if i tell them its a standard engine do the know enough? I really don't know what info or measurements are needed for a head swap. The engine is open now but not at home..and will fits my headers still?
(Btw 300-350 HP would already be fine for me..)

[steve25]

I really do not think you want to shoot for more than 1 hp per CID if you want good everyday street manors out if that motor !
I intake air flow level of 225 cfm @.500" @ 28" test pressure will serve you well , I do not know what port non off the shelf port runner sizes KRE offeres , but I would not go for anything larger than 170 CCs!

As far as you spending big bucks on the custom KRE heads that's up to you as the air flow level I posted about can be had out of your stock heads thru reworking them.

If your going for the KRE heads you should try and rebuild the motor with Pistons that will work with a 14 degree valve inclination angle as this will provide the best breathing , but in each cylinder bore at the top you will need to add a valve chamfer as many of the 67 and up motors have.
Once you settle on a bore size and find out what the deck clearance is then KRE can CNC you up a head with the info you will provide.

Be aware that you will also need different rocker, push rods and a set of poly locks to adjust the valves .

[Hanzel]

I made my decision and keep my 326 engine original. New seat en and new harderned valve's will be installed... Bit too "risky" and I know what I have now, and the cost will be almost the same...