"Hot Slot" equipped cast iron intake manifold modifications..

[Camaroon]

Looks like we have continued dissent in this thread on the correct installation location for the "tin plate" or "stainless steel baffle " that is used to reduce hot slot exhaust heat from direct contact with the forward portion of the carb base.
69pace says:  The "tin plate" goes on top of the manifold then the fiber gasket then the carb. 
jeff68 disagrees with 69Pace, jeff says: Intake manifold, then gasket, then heat shield, then carb
JohnZ agrees with jeff, John says: use a stainless steel baffle between the carb baseplate and the carb gasket

[tmodel66]

The AIM shows gasket on the intake then baffle on page L35/L34 A-6. Although it's BB it is the lower HP with Quadrajet carburetor. The baffle is for protection of the carb so Figure the application would be same for all the Quadrajets?

[JohnZ]

The AIM shows gasket on the intake then baffle on page L35/L34 A-6. Although it's BB it is the lower HP with Quadrajet carburetor. The baffle is for protection of the carb so Figure the application would be same for all the Quadrajets?

That's correct - the L-78 had an aluminum intake with a Holley, and didn't have the "hot-slot".

[Mike S]

 I've read that the metal plate against the throttle base doesn't seal good in some situation when there is a slight warp in the baseplate.
I've been using the gasket-metal-gasket stack for years with success (along with plugged slot holes).
The extra ~.030" from the second gasket made no difference in the choke function at all.


Mike

[69pace]

I've read that the metal plate against the throttle base doesn't seal good in some situation when there is a slight warp in the baseplate.
I've been using the gasket-metal-gasket stack for years with success (along with plugged slot holes).
The extra ~.030" from the second gasket made no difference in the choke function at all.


Mike

If the Hot Slot is still active the fiber gasket will roast out in no time leading to leaks. The tin conforms to the surface and doesn't leak if its is the right gasket. It has to be the thin one not the 1/4 inch pseudo spacer. 

[1967RS/SS]

What is the method to use when using headers with original cast iron intake/Q-jet carburetor setup?  Would you still need to block these holes?   

[bertfam]

What is the method to use when using headers with original cast iron intake/Q-jet carburetor setup?  Would you still need to block these holes?

Yes. The hot slot "fix" is so you don't warp the Rochester carb. (or start a fire!!)

Ed

[1967RS/SS]

What is the method to use when using headers with original cast iron intake/Q-jet carburetor setup?  Would you still need to block these holes?

Yes. The hot slot "fix" is so you don't warp the Rochester carb. (or start a fire!!)

Ed

What about the exhaust manifold heat valve?  Just leave it off if you have headers?

[Mike S]

I don't think you can use it with headers because how would it fit? I have never seen it like that anyways.

Mike

[1967RS/SS]

Need some help guys.  I am at the point now where i will be putting my quadrajet back onto my iron manifold.  After reading about the hot slot problems I am scared of a fire!

I plan to plug hot slot holes with steel plugs and remove heat riser flapper (doesn't get too cold here in southern California).  i will be leaving the riser body in place for that original look.

Do I still need to use the stainless steel baffle underneath the gasket?

Also, the guy that rebuilt my quadrajet included what looks to be a spacer with the rebuild.  It's about 1/4" thick and seems to be made of plastic.  Do I need this as well?

[JohnZ]

I plan to plug hot slot holes with steel plugs and remove heat riser flapper (doesn't get too cold here in southern California).  i will be leaving the riser body in place for that original look.

Do I still need to use the stainless steel baffle underneath the gasket?

Also, the guy that rebuilt my quadrajet included what looks to be a spacer with the rebuild.  It's about 1/4" thick and seems to be made of plastic.  Do I need this as well?

You must have removed the headers you mentioned earlier if you're going to use the heat riser valve; there's no way to use the heat riser valve with headers.

The stainless baffle goes under the carb on an L-35, on top of the gasket, as shown in the Assembly Manual.

[1967RS/SS]

I plan to plug hot slot holes with steel plugs and remove heat riser flapper (doesn't get too cold here in southern California).  i will be leaving the riser body in place for that original look.

Do I still need to use the stainless steel baffle underneath the gasket?

Also, the guy that rebuilt my quadrajet included what looks to be a spacer with the rebuild.  It's about 1/4" thick and seems to be made of plastic.  Do I need this as well?

You must have removed the headers you mentioned earlier if you're going to use the heat riser valve; there's no way to use the heat riser valve with headers.

The stainless baffle goes under the carb on an L-35, on top of the gasket, as shown in the Assembly Manual.

Yep, never installed the headers and just kept the manifolds. Thanks for your help...

[mickeystoys69RSSS]

Is there any way to tell if my intake has a cross over without removing the carb? I know I have a riser valve but I have no idea if it works or has been modified?

[Boston14]

What year, engine, and intake casting number do you have?

[mickeystoys69RSSS]

What year, engine, and intake casting number do you have?

late '68 built 1969 Model L34 396/350HP with TH400 Auto trans. The intake casting number: 3931067 cast date H 5 8 or August 5th 1968 time 11:00