holley metal plate question

[Werner R.]

i'm using the 4160 model 3310-3 on top of an edelbrock dual plane intake manifold. my shop told me to use a metal plate between the carb and manifold, and to use two gaskets, one on either side of the plate. any thoughts???

[John H.]

Re: holley metal plate question

Werner -

What problem are they trying to solve with that suggestion? There's no "hot-slot" on an Edelbrock manifold.

[Joe L.]

Re: holley metal plate question

i'm using the 4160 model 3310-3 on top of an edelbrock dual plane intake manifold. my shop told me to use a metal plate between the carb and manifold, and to use two gaskets, one on either side of the plate. any thoughts???

Werner-----


No need whatsoever for that configuration. You can use either just a standard Holley base gasket or a thick, insulator style gasket. If you have hood clearance for it and originality is no concern, I recommend the latter. Easily available in the aftermarket from Holley or otherwise.

[Werner R.]

Re: holley metal plate question

john
i thought it was to prevent a leak, as the ovrlap between the aluminum manifold and the base of the holly is quite narrow in parts. the plate, being stong flat metal adds a stiff support, as i asume the carb body, being softer would not. i mesaured the overlap once, and as i recall it was in places around 1/4 inch. does this make sense? 1/4 inch would seem enough.

[Joe L.]

Re: holley metal plate question

john
i thought it was to prevent a leak, as the ovrlap between the aluminum manifold and the base of the holly is quite narrow in parts. the plate, being stong flat metal adds a stiff support, as i asume the carb body, being softer would not. i mesaured the overlap once, and as i recall it was in places around 1/4 inch. does this make sense? 1/4 inch would seem enough.

Werner-----


I don't think the plate will make ANY meaningful difference in support for the carb. For one thing, these plates are quite thin. When used originally, these plates always served as a baffle to protect the carb from direct exhaust heat which passed through the "heat slot" of some Chevrolet manifolds. They never had any other purpose, at all, and I really don't think they will serve any other purpose. The 1/4" "overlap" is PLENTY for support.

[Stuart F.]

Re: holley metal plate question

Wasn't there a plate once used on some big blocks that not only was for insulating the carb from direct exhaust slot heat, but extended out beyond the carb base for an inch or more to deflect radient heat from the manifold surface as well? can't recall the application, and I'm sure that wasn't what they had in mind, but just a thought. I'm full of those, Sorry.

Stu fox

[Joe L.]

Re: holley metal plate question

Wasn't there a plate once used on some big blocks that not only was for insulating the carb from direct exhaust slot heat, but extended out beyond the carb base for an inch or more to deflect radient heat from the manifold surface as well? can't recall the application, and I'm sure that wasn't what they had in mind, but just a thought. I'm full of those, Sorry.

Stu fox

Stu-----


The carburetor INSULATION that you described was used for the 1970 model year for cars with EEC (NA-9) although it's possible it was also used for some 1971's. However, this INSULATION had absolutely no relation, whatsoever, to the thin, stainless steel BAFFLE used for some pre-1970 applications.

The pre-1970 stainless steel BAFFLE was designed ONLY to protect the carburetor from the direct exhaust GAS passing through the "heat slot" of some manifolds. In fact, the BAFFLE was used ONLY with applications having the "heat slot". Non "heat-slot" applications used no BAFFLE.

For the 1970 model year, the "heat slot" was eliminated from ALL Chevrolet engines. So, there was no need for a BAFFLE to protect the carburetor from exhaust GAS. The INSULATION was an aluminum plate with a THIN carburetor base gasket stapled to the plate. The combination of the aluminum plate with the thin gasket did help insulate the carb from exhaust HEAT passing up through the manifold. However, the primary purpose of the INSULATOR was to protect the carb from RADIANT heat effusing up from the manifold heat CROSSOVER and otherwise from the intake manifold. The aluminum plate, which extended well beyond the perimeter of the manifold carburetor flange, served to insulate the carburetor from the heat. Primarily, this was designed to help minimize fuel evaporation from the carb and not to otherwise protect the carburetor.

There were INSULATORS configured to work with both Rochester and Holley carbs but, except for some possible 1971 usage, they were not used after 1970. For 1971 and later, a thick carburetor INSULATOR was used. This was, basically, just a thick (~1/4") carburetor gasket. These work quite well and I recommend them for any application, whether originally used or not, where hood clearance is not compromised.

Pictured below is the GM #3969837 INSULATOR used for 1970 NA-9 applications with Rochester carb (base, L-46, and LS-5).

[Stuart F.]

Re: holley metal plate question

Joe;

Thanks for clearing that up. That's exactly the animal I was thinking about. I see it has the nice cutout for the choke stove there too. One can't help but wonder if something like that would be effective for those of us still dealing with fuel evaporation problems with our old AFB equipped L-76's. I've tried aftermarket insulators made of sandwiched plates and gaskets w/o much improvement w/i the hood clearance limitations. I guess the steel fuel lines with water manifold mounted filter and hot air choke tube are just too much to overcome, and still keep the stock appearance.

After today's drive, I used a big fan in front of the car to blow air through the radiator to help cool it down. Seemed to help, but I can't be sure (see our previous discussions about "stinky garages").

Stu Fox