[67Twistytee]

I am going through an engine rebuild that includes plans for a new exhaust. I've been planning on using the repro RA manifolds and realize this will eliminate my heat riser. Does this have much (if any) impact for a '67? I assume I don't need the intake heat assist living in NC. On a related note, has anyone blocked the exhaust crossover on the intake manifold and gone done the route of electric choke? I like the idea of reducing heat around the carb and fuel lines, but I don't want to give up my original carb for an electric choke Qjet. Thoughts?

[Baron Von Zeppelin]

Most everyone has been doing the flapper delete at every given chance.
Even on stock log manifold applications.

Wouldn't fill/block the crossover ports in heads or intake.
It messes up exhaust flow equalization/pulses in those associated ports unless you have them filled-reshaped-ported correctly.
Its better left to the race car purpose apps.

But would have the small exhaust ports under front of carb filled - or thread tapped and pipe plugged , on the intake.
If it is a stock 67 intake.
That was a 1 year deal / overkill.
Would still use the stainless steel plate between carb and intake.

[67Twistytee]

Thanks BVZ.

From searching other posts here, that's seems to be the consensus. Everything is stock and original including the intake and carb. I plan to plug the front channel, but the builder I'm working with isn't a fan of the '67 intake and fueling design given all the potential for heat build-up. I understand his point but want to keep things stock looking if I can still get reasonable street performance.

[428goat]

Got a friend in a 67 convert, beautiful car, 10 years in a row gold at the nationals goes to the strip and runs a 11.95 with a 67 manifold. Nothing wrong with a 67 manifold. Everything looks stock.

[Baron Von Zeppelin]

If he gets insistent enough to persuade you , I have an extra pair of 670 heads that have had the exh. x-overs filled in. And can sell them reasonably.

[b-man]

Originally Posted by 67Twistytee

I am going through an engine rebuild that includes plans for a new exhaust. I've been planning on using the repro RA manifolds and realize this will eliminate my heat riser. Does this have much (if any) impact for a '67? I assume I don't need the intake heat assist living in NC. On a related note, has anyone blocked the exhaust crossover on the intake manifold and gone done the route of electric choke? I like the idea of reducing heat around the carb and fuel lines, but I don't want to give up my original carb for an electric choke Qjet. Thoughts?

Keep in mind that the factory decided to eliminate the flapper on 1969 models that had the same exact manifold stove heated coil divorced choke design as your '67. So it would seem that choke actuation won't be affected by either removing or disabling the heat riser flapper valve, or by going to the RA/HO manifolds.

1969 design shown at the top, 1967 below.

[67Twistytee]

He is a performance/race builder over restoration for sure, but he's been working on Pontiacs his whole career so he can handle a restoration build. His point on '67 GTOs is they are set-up from factory to cause trouble with modern fuels - exhaust cross-over, manifold riser, channel at front of intake to "warm" carb, fuel lines running past water neck with fuel filter sitting right on top of intake, pancake air filter getting hot and grabbing hot air from engine bay, etc. Anything you can do to take heat away from the fuel bowl and inlet is a good move in his mind. Modern fuel injection aside, there's no way you would design a fuel intake system like this today with low octane ethanol fuels in mind. I can't argue with that.

Thanks for the offer on the heads. Mine are original and uncut, but Im leaning towards opening them up when he does the valve work. This isn't a show car and they're never going to run great with closed chambers.