fuel injection gaskets

[John D.]

FYI: '57 to '65 fuel injection intake to head gaskets have NO metal plate on the long gaskets. Yes I know various companies advertise them as such but that info is incorrect. Just got a phone call with that question.

John D

[Dan H.]

Re: fuel injection gaskets

John, probably true, but is unseen, and anything that keeps heat away from the FI unit is welcome.
Dan

[Edward J.]

Re: fuel injection gaskets

John, google small block chevy intake gasket set. and find Mr Gasket part no. 101B and see if this works for you, not GM but has metal block off plates.

[John D.]

Re: fuel injection gaskets

Ed, I don't need or want the block off plate.
An Example for you all. I just receive a 63 FI to restore. Was off the car for the first time. Still has the original intake gaskets stuck to the base plate. No sheetmetal plate.

[Joe L.]

Re: fuel injection gaskets

Ed, I don't need or want the block off plate.
An Example for you all. I just receive a 63 FI to restore. Was off the car for the first time. Still has the original intake gaskets stuck to the base plate. No sheetmetal plate.

John-------


According to GM, there were two gasket sets used for 1957-65 FI applications. In PRODUCTION gasket sets were not used. However, the component parts of the gasket sets, which had individual, PRODUCTION-only part numbers, were used. In the VAST majority of such cases, the gasket sets, available under their own part number in SERVICE, would have contained the same pieces as used in PRODUCTION.

For 1957-59 the gasket set used was GM #3734115. This is the same gasket set used for all other small blocks of the period and includes an open cross-over passage.

For 1960-65 the gasket set used was GM #3772384. This gasket set was uniquely applicable to 60-65 with FI. I know nothing about this gasket set but, presumably, it was different than the 3734115 which continued to be applicable to other small blocks. All I could suppose the difference was would involve some difference to the cross-over area. That could have involved either a no hole cross-over area (i.e. gasket material uncut for a crossover) or a standard gasket with a plate installed. Of course, all this is just supposition on my part because, as I mentioned, I have no knowledge of the 3772384.

I can say this, though: if I were installing a gasket set on a 1957-65 FI Corvette, I'd definitely want one with block-off metal plates installed in the cross-over. That would offer the best protection for the FI adapter (manifold). As you know, they don't make these things anymore so protecting the ones that exist as best we can seems like a smart thing to do.

[Bob J.]

Re: fuel injection gaskets

Ed, I don't need or want the block off plate.
An Example for you all. I just receive a 63 FI to restore. Was off the car for the first time. Still has the original intake gaskets stuck to the base plate. No sheetmetal plate.

It does not need a block-off plate since the adapter manifold is blocked........there is NO heat crossover on a FI manifold .
You would be blocking a blocked passage.
Bob Jorjorian

[Joe L.]

Re: fuel injection gaskets

It does not need a block-off plate since the adapter manifold is blocked........there is NO heat crossover on a FI manifold .
You would be blocking a blocked passage.
Bob Jorjorian

Bob-------


Yes, there is no cross-over on an FI adapter. However, there are cross-over passages on FI cylinder heads. With a standard gasket, this causes direct exhaust gasses and heat to directly contact the adapter manifold. Is this a serious problem? No, it's not. But, it would be better if the gasses/heat were not allowed to come in direct contact with the adapter manifold. I think it will be found that adapter manifolds that have come into direct contact with gasses/heat will show signs of erosion in the cross-over area.

[Bob J.]

Re: fuel injection gaskets

Joe
I don't remember that gasket plate being used in ANY SBC passenger car engine.
I'm sure if GM thought it would help heat related problems it could / would have been used.
Like everything else, everybody is entitled to their opinion.
Bob Jorjorian

[Don H.]

Re: fuel injection gaskets

I agree with keeping the gases away from the adapter plate for the reasons stated (heat and corrosion). I use the block off for both of my FI cars. Keep in mind GM never planned or cared about 50+ years of use. JMHO, Don H.

[Stuart F.]

Re: fuel injection gaskets

I recall, back in the day, we used gasket sets from our local Chevy dealer parts dept. that had metal plates in the crossovers that had small oval holes in the centers (like about 1/2") primarily on our carbureted engines. Would these have been for truck engines? Our 56/57 Chevy's also had the balance tube crossovers from one exhaust side to the other, and we used to cap them off to get maximum sound from our glaspak dual exhausts. Does this sound right? Reason I ask is my long term memory has slipped a bit, but I know I'm not immagining these things.

Stu Fox

[John D.]

Re: fuel injection gaskets

Joe, Nice recap on the part numbers etc on the two gasket sets. The major difference between the '57-'59 ad the '60'-'65 is in the size of the port holes.
You can use the repro or later style gaskets on all '57 to '65 FI cars. But you can NOT use the '57-'59 gaskets on the later years.
If you do you are taking a chance of a serious vacuum leak.
Story: Long ago I restored a midyear FI unit for a restoration shop. They installed the '57 style gaskets on this car becauses the NOS set they had included the end rubbes with the tab and GM logo.
So the FI unit ran like crap. Turned out the problem was the intake to head gaskets.
I guess you could easily use the intake gaskets with the medal plate on the FI unit. But that is not the point of my posts. The point was/is to say to you that is not what they were intended for by GM. As Jorjorian and a few others have said.
FI cars: No medal plate.
Carb cars: Medal plate.

[Joe L.]

Re: fuel injection gaskets

I recall, back in the day, we used gasket sets from our local Chevy dealer parts dept. that had metal plates in the crossovers that had small oval holes in the centers (like about 1/2") primarily on our carbureted engines. Would these have been for truck engines? Our 56/57 Chevy's also had the balance tube crossovers from one exhaust side to the other, and we used to cap them off to get maximum sound from our glaspak dual exhausts. Does this sound right? Reason I ask is my long term memory has slipped a bit, but I know I'm not immagining these things.

Stu Fox

Stu-------


Yes, the gaskets you described were used for some truck applications. However, the same type gaskets came back and were used for some passenger car applications in the mid-to-late 70's. I believe the use was somehow related to emissions systems.

[Joe L.]

Re: fuel injection gaskets

Joe, Nice recap on the part numbers etc on the two gasket sets. The major difference between the '57-'59 ad the '60'-'65 is in the size of the port holes.
You can use the repro or later style gaskets on all '57 to '65 FI cars. But you can NOT use the '57-'59 gaskets on the later years.
If you do you are taking a chance of a serious vacuum leak.
Story: Long ago I restored a midyear FI unit for a restoration shop. They installed the '57 style gaskets on this car becauses the NOS set they had included the end rubbes with the tab and GM logo.
So the FI unit ran like crap. Turned out the problem was the intake to head gaskets.
I guess you could easily use the intake gaskets with the medal plate on the FI unit. But that is not the point of my posts. The point was/is to say to you that is not what they were intended for by GM. As Jorjorian and a few others have said.
FI cars: No medal plate.
Carb cars: Medal plate.

John-------


I don't understand that, at all. For any given year, the cylinder heads used for FI applications were the same as those used for many non-FI applications. For example, the cylinder heads used for 1964 L-76 were identical to the cylinder heads used for 1964 L-84. Yet, the L-76 used gasket set GM #3734115 while the L-84 used gasket set GM #3772384. In addition, the 3734115 was applicable to all 1957-59 applications and all 60-67 small block applications except FI.

Are you saying that the port size of the 1957-59 adapter manifold was the same as carbureted manifolds but the port size of the 1960-65 adapter manifold was larger than that used for carbureted manifolds? I do not understand what the purpose of that would have been if the port size in the heads was the same (which, as I mentioned, it was). If so, an "instant" port mismatch would have occurred. Not a good thing, at all, for performance.

The reproductions of the GM #3734115 have no metal plate at the cross-over. The reproductions of the 3772384 do have a metal plate at the cross-over. Of course, the reproduction source may have gotten it wrong but, since the reproduction is a GM Restoration Parts item, the manufacturing source at least had access to the original blueprints. Still, they could have gotten it wrong. Anyone out there have an NOS example of the 3772384? Also, I'd like to see an overlay comparison of the port size between the 3734115 and the 3772384.

[John D.]

Re: fuel injection gaskets

Joe, I have a set of the early gaskets around here. And the later style too. The gaskets on the '57-'59 are smaller. Outside dimensions are smaller. Ports are smaller. Too small. That's all I can tell you.
One of the gang here ran into this problem. He used the '57 style gaskets on a '63 FI unit. Not saying who. He had a major leak. Back to work. John D

[Stuart F.]

Re: fuel injection gaskets

Thanks Joe. Guess my memory isn't all that bad.

Stu Fox