AFB Carburator to Intake Gasket "401"

**Scotty** · 06-27-2005, 07:23 PM

Hello,
I have 63 401 LeSabre with a Carter AFB 3503S 4 Barrel (car came with a 2 barrel I changed it to 4 some years ago) There is a channel or grove in the intake manifold (in a u shape) that ends have ports that lead deep into the manifold. I am having problems finding a gasket to match the grove. The rebuild kit for the AFB came with one with cut outs for the channel or grove. I need to replace the gasket but can only find ones for Rochester or Elderbrock afb. The Elderbrock gasket fit,but covers the grove. If I use the Elderbrock will it make any difference in how the car runs? If so any idea where I can locate the correct gasket?
Thanks Scotty

**1loinvicta** · 06-27-2005, 08:59 PM

I'm not an expert on this but from what Ive been told by several "old timers", one who rebuilt carbs for most of his life. Those grooves and ports need to be covered. When this gentleman rebuilt my carb he knew by looking at it that this gasket was missing and told me to replace it with a steel one. I couldnt find a steel one so I made it myself. So far everthing is working much better than it used to but I havent put many miles on it since the rebuild. Also mine is a 61 401 with an original rochester 4bbl but I think its the same idea. Hope this can help. TR

**sicksteve** · 06-27-2005, 10:23 PM

yeah, the grooves should be covered; some are for hot coolant recirculation. Once when I didn't put on the right steel gasket, the car ran terribly.

BTW: who makes a good metal gasket for this purpose now, something that acts as a good heat insulator?

**Scotty** · 06-28-2005, 05:45 AM

Thank you, I have heard that there is a metal gasket for the carb to manifold but have never see anything other than aftermarket heat shields.
Scotty

**wildcat2** · 06-29-2005, 04:24 AM

Try Classic Buicks

http://classicbuicks.com/fuel_intake.htm

**BillK** · 06-29-2005, 04:13 PM

Scotty,
I am almost certain that Fel-Pro has the correct gasket in thier catalog. I can't check here at home, but any "real" parts store with an actual catalog to look in should be able to get it for you. Its no different than any other GM with an AFB. The groove you are talking about is usually an exhaust heat channel to heat the carb for cold weather driveability. Quadrajets had them and used a thin sheet metal gasket on the manifold.
Hope this helps,

**Scotty** · 06-29-2005, 05:52 PM

Thanks to all that have reponded to my questions. As one might guess one leads to another. Can anyone tell me what kind of gasket sealant (if any) to use on the carb to manifold? What about the intake manifold gaskets? I replaced them with the fel-pro OEM steal gaskets with RTV around the coolent passages and flang sealer on the rest. It now leaks, I noticed that the groves around the gasket are slightly hanging over the side of the manifold. I believe this is where the leak is. I am not real excited about trying another set of steal gaskets. Any thoughts or advise would be apprecated
Scotty

**BillK** · 06-29-2005, 06:12 PM

Scotty,
Are you sure you have the right gaskets ? Wish I had my catalog rack here at home

I use a bit of RTV on the water ports and Permatex Hi-Tack spray on the rest of the metal gaskets. Where exactly is it leaking ? If the heads or block have been milled excessively, it can cause a problem. Any chance of a picture ?

**Scotty** · 06-29-2005, 07:05 PM

I do not think that the heads have been machined. My dad has had the car since 1972 and gave it to me in 1998 it has only 51,000 on it. The bolts line up perfect I added the 4 barrel manifold a few years ago so I know that it was not machine to match modified heads. If the heads where milled wouldn't that be a problem? The groves are hanging over (or right on the edge) the outside of the manifold. I got the gaskets from Classic Buick on the box it said 401 and 425.
The car is idling rough now and when I sprayed 10w40 around the gaskets RPMs seem to increase. I was told that this is one way to check for a leak in the manifold. However the fast idle screws on the carb do respond and the car is not running rich. So far this is one of those cases where it worked better before I worked on it.
By the way the reason I was replacing the intake manifold gaskets was because the car would blow a little water out the tale pipe when first started. I was hoping that is was because of water leaking in through the water passage in the manifold into the heads. No water in the oil pan and no oil in the radiator.
Thanks Scotty

**BillK** · 06-30-2005, 09:30 AM

Scotty,
The water out of the tailpipe is probably normal, just condensation from sitting. FelPro lists the intake gasket so it should not have to come from anywhere special. If you spray carb cleaner around the gasket and the idle picks up, then it is leaking.