Grebs

I pulled the carb on my 62, 327/300 Carter AFB to check the base gasket for a vacuum leak and was surprised to see there was only one gasket and an insulator plate.

Shouldn't there be another gasket above the insulator (thin plate)?

My problem is that it recently began to idle very rough and hesitate through initial accelleration. Also, idle won't back down below 1000 rpm. Runs fine above 2000 rpm.

All looked ok to me on the carb, but I suspect a vacuum leak. When I spray carb cleaner in the intake I get more rpms instead of less.

Joe

plaidside

That is correct. The gasket on the intake, then the stainless plate and then the carb.

Geek's 65

With the insulator plate in between the gasket and the stainless? Make sure you have that stainless in there or the exhast crossover will eat the bottom of your carb. There is a post from John Z that talks to plugging the crossover on the manifold. If you have the carb off you might want to think about it.

Geek

Grebs

You guys are great, thanks;

claf

I was under the impression that an insulator was only necessary when using a cast iron manifold. I have never had an AFB using the insulator/stainless/gasket on an aluminum intake . Bob

Geek's 65

You could be right. When I wrote that I didn't realize we were talking about a 62. For whatever reason I thought it said 65. Sorry about that.

Geek

OC-1

62, 300hsp uses a cast iron manifold, a stainless gasket and a thick insulator plate and composition gasket.

tach drive 61

ok joe now for me intake/gasket/SS /insulater /carb ????

RoadKing96

Yes please.... I just got done rebuilding my Carter AFB 3721 and noticed there were three things under her. My order was Insulator/SS/Gasket on top, but it sounds like that maybe wrong. Plan is to do some vacuum checks tomorrow morning as I'm having a hard time keeping an idle.....

Where would us common folk find information like that? In Service Manual? Or does someone have the gasketing order documented...?

Thanks in Advance,
RK

62Jeff

Heck I thought OC-1's post in this thread answered the ordering questions, guess I read wrong!

RoadKing96

I seem to have read a couple different possible answer's and didn't realize that OC-1's answer was it.

The other simple question I was trying to understand is where this information was coming from....memory, the way their's is currently, from a document/article. Just trying to understand the source and validity, so I can make sure it is correct, that's all.

RK

62Jeff

Oh no I agree, I sent tach drive 61 to this thread earlier tonight in a reply to his own "what about the gaskets" thread. But it's looking like I provided possibly bad data.

Looking at my 1962 AIM for RPO 583, which I believe is the 300 horse engine, it shows:

Intake
Gasket
Insulator
Baffle

Not sure what that data tells us though. I searched earlier this evening for an older thread with photos that clearly showed the arrangement, but all of the photos had expired and were no longer available.

JohnZ

How about a clue for which engine/year you're asking about? The combination for a '64 L-75 (which used the 3721) is shown in the '64 Assembly Manual in section L75, sheet 1.00, items #31,32,33. The gasket goes on the intake, then the insulator, then the baffle, then the carb.

Fawndeuce

For a '62 300

Intake
gasket
Phenolic spacer
Metal baffle
Carb




Paul

RoadKing96

Sorry John, I have a '64. The current engine I am referring to is a 327 but nothing original or to special. It's a cludge of vette parts from years ranging from '64 - '67. I do not know internals of motor, except it has solids and a slightly bumpy cam. It currently has a cast iron manifold with aformentioned 3721 Carter AFB.

I know my order is not reflective of yours as listed, so I'll recheck and try per "gasket goes on the intake, then the insulator, then the baffle, then the carb".

Appreciate it,
RK

stevelang

i have seen a really old diagram showing a second fiber gasket above the insulator and gasket cement on top of the ss plate.

silver837

11 year old thread.

stevelang

it may be an old thread but I am working on the issue right now with a 459 cast intake manifold and a carter afb. a lot of answers do not mention the 2nd fiber gasket on top of the phenolic spacer. nor do they say anything about gasket cement on top of the SS baffle i think I found the picture on a Cadillac web site along with much discussion about the unusual layering of items between the intake and the carb. the consensus on the cad web site was to use the second gasket. think about it. without that 2nd gasket there would be 2 opportunities for vacuum leaks in areas where hard surfaces meet. 1 opportunity is lessened with gasket cement and the other is dealt with by using the 2nd fiber gasket.

i am late to these forums as I was not involved with corvettes for a few intervening decades. however, they have been very helpful to me, especially the older threads.