Slick 60's

Hi,

I finally have my 66 F100 apart and I've removed the exhaust manifolds due to high end exhaust leaks. Im not quite sure I have the right gaskets and after looking through LMC and Dennis Carpenter Im even more confused.

Is the heat riser supposed to have gaskets on either side of it? If so who sells them? My heat riser is forever frozen in the open position. Does it matter? Is it just for cold start up?

As always thanks for the great information I get from the members here!

My 64s exsaust manaphold is all ate up. I got a set of split header for it. I haven't put them on yet.I hope they let the 223 breath better.

Since you have it apart, now is a good time to eliminate the heat riser, if you so desire.
You will need the following parts instead, if you wish to keep it looking stock, and do not want to use headers:
1. Driver's side exhaust manifold for a '73 - '76 F-150 with a 390 (Get them both new off evil bay, the originals tend to warp pretty badly.)
2. The "Y" cross-over pipe for a '73 - '76 F-150 with a 390
3. The doughnuts, bolts etc.

This will give you a bolt-on solution for a stock single exhaust setup without the riser.
If you want to go dual exhaust, then you will still need to replace the driver's side exhaust manifold.

Thanks for the advice! I'd love to do headers but just can't afford it right now.

Does anyone know about the heat riser as to how it functions once the truck is warmed up? Does it just stay open?

it should. i think the spring is heat sensitive.

Great thanks for the reply! Now if I can get the right gaskets I should be good to go.

i just went out and looked at the set up in my shed and the lower gasket appears to be the same donut gasket that is used on the non heat riser style to the exhaust pipe. i have the heat riser separated from the manifold and don't see a gasket between that and the riser. if there was one, it disintegrated long ago and there is no evidence of one. if there was one it was very thin because when i took it apart it was tight and did not appear to be leaking.

Thanks for checking on those gaskets! I appreciate it!

So some one mentioned getting rid of the heat riser. What would happen if you did? Is it not really needed?

The heat riser is designed to speed up engine warming by redirecting exhaust from one side to the other, under a cross-over passageway within the intake.
When cool, the coil spring rotates the flapper closed. As it warms up, the thermostatic spring relaxes, which allows the counterweight to rotate the flapper valve open.
Simple technology, and not really needed in warm climates.
A properly tuned and sound engine will have no problems with the heat riser valve. However, an engine out of tune or burning oil will produce excess deposits which will foul the rotating valve and gum it up.

Thanks Michelle! I'll pick one up!

Good luck with getting a gasket that works...I tried finding one and could not get a direct match. The ones that were 'close' all blew out within a few time of use. If someone can come up with an exact match part number I'd love to know it. The sealing surface on these is really small.

The original Ford gasket is discontinued, but there are still some on a few dealer's shelves. I bought a half dozen or so. If you can't find one let me know and I'll sell you one of mine.

The heat riser stuck open isn't a bad thing. I've wired mine open so that the gaskets hopefully won't be forced to blow out. I also have dual exhaust on mine; you don't need to change manifolds to put duals on but you're stuck with the riser valve.