[alanmay0]

Does anyone know how to stop the paint from discoloring on the intake manifold. I'm talking about the center crossover port. I have a 1967 GTO and I am always repainting this location on my car. I think I heard of a way to block this cross over sometime back but have forgotten how.

Thank you
Alan Mayhew

[69 Limelight]

This is what I do to the exhaust crossover of the intake manifold, as well as the exhaust side of the cylinder heads where they burn the paint off and rust.

I spray a couple coats of high temperature aluminum (header) paint on these areas before the Pontiac Blue. Then spray the entire part with Pontiac Engine Blue (mine happens to be a 69). Then when I first fire engine I don't let it get too hot and then let it cool. (I know nearly impossible when breaking in a flat tappet cam but, I use hydraulic rollers.) Do this a couple of heat/cool cycles and has worked well for me. Probably 12-15,000 miles since last time and still looks good.

[Greg Reid]

Are you using a choke?
Blocking that runner will interfere with it's effectiveness....besides, the paint isn't usually the point of blocking that off, although it is a side benefit.
I have been using the high temp silver paint trick as well. It improves the appearance of the hot spots quite a bit..

[Stuart]

I've done the high temp silver paint trick with reasonable results, in my case it still eventually discolored to some extent but it took longer and wasn't as bad.

[694.1]

I normally block the driver's side of the port.
Choke still works, paint looks better. Carb runs cooler.
Winner!

[alanmay0]

thank you

[NeighborsComplaint]

Just painted the exhaust ports on my heads with VHT flameproof (exhaust header paint). They make a silver and a blue so I dispensed from the cans into my airbrush (through a soda straw) until I had a reasonable match to the Pontiac Metallic Silver Blue .I sprayed a silver coat followed by the silver blue.

I will follow the curing process and see how the header paint holds up and get back to you.

[phil400]

I did several coats of Header paint before applying the engine paint, pics show one summer later, there's discoloration but atleast it's not rusty look, car averages 2000~2200 miles a year approx from May to November.

[alanmay0]

Thanks but I have heard of intake manifold gaskets with this center ports not cut into the gaskets so when you put on the gasket it blocks the exhaust from crossing over. Anyone heard of this???

[NeighborsComplaint]

All the performance intake sets come with inserts that block off the heat risers. Edelbrock includes both a full block off and a partial block off plate. The intake still gets hot enough to discolor the paint even if blocked off though.

[shaker455]

Gasket material will burn thru ,
Some people have used stainless shim stock to close the ports off with the use of standard gaskets.
I just modified an old P4B for my 67 GP removing the crossover RAIV/HO style.
Car runs "much smoother without all that heat.
In this cases I machined up some block off plates

[NeighborsComplaint]

Originally Posted by shaker455

Gasket material will burn thru ,
Some people have used stainless shim stock to close the ports off with the use of standard gaskets.
I just modified an old P4B for my 67 GP removing the crossover RAIV/HO style.
Car runs "much smoother without all that heat.
In this cases I machined up some block off plates

The Mr. Gasket and Summit paper gaskets will burn through as they use the gasket material to block-off the heat riser by not "punching" the crossover hole. I used to cut stainless steel sheet stock to the shape of the heat riser gasket opening and glue them between the gasket and head using those gaskets but found the inserts supplied with the better gasket sets worked just as well. The FelPro and Edelbrock sets use a rigid, reinforced insert made from exhaust gasket material that does not burn through.

[shaker455]

Originally Posted by NeighborsComplaint

The Mr. Gasket and Summit paper gaskets will burn through as they use the gasket material to block-off the heat riser by not "punching" the crossover hole. I used to cut stainless steel sheet stock to the shape of the heat riser gasket opening and glue them between the gasket and head using those gaskets but found the inserts supplied with the better gasket sets worked just as well. The FelPro and Edelbrock sets use a rigid, reinforced insert made from exhaust gasket material that does not burn through.

Sure,
I've also used the Fel-pro 1233

[grandam1979]

Felpro sets come with the block off plates even has a dimple in the middle to line it up.

[alanmay0]

thanks I ordered some from summit