Intake Manifold

[Lee McGlamery]

Hi - I have a 70 350/350 with all matching numbers except the casting number on the intake is 3927184 which is a 69 casting number. The date on the intake is from June 69. I know that parts for the cars normally precede the car build date by about 3 months but I also know that the production of the 1970 cars was somewhat unusual.

Is anyone aware of 69 intakes that were installed on 70 cars? My car build date was during February 1970. Also what is the difference between a 69 and 70 intake? I want to put the proper intake on the car but I also want to make sure that the one that is on it is not the right intake.

Thanks

Lee

[Joe L.]

Re: Intake Manifold

Lee-----

This kind of a tough one. As you may be aware, 1970 Corvette production did not begin until January, 1970. However, other 1970 Chevrolet production did begin in the early fall of 1969. For the most part, only Corvettes and Camaros got the "late start".

The 1970 Corvette base engine was the same basic engine as used in other Chevrolet cars although, I believe, the engine manufacturing code was unique to Corvette engines. While I consider it unlikely that a 1970 Corvette-destined engine built in the usual 2 to 6 weeks prior to the car's build date could have had one of the 1969 manifolds, perhaps your engine was built somewhat earlier than normal 1970 Corvette engines. Check the engine block casting date and the engine assembly code (date) stamped on the stamp pad. If your engine was actually built in June or July 1969, then I would say that the manifold could possibly have been on it from the beginning. If your engine was built in January or February 1970, then I think that it's a lot less likely that the manifold was originally on the engine. But, it's NOT impossible. The problem would be documenting it.

The 1969 GM #3927184 manifold and the 1970 GM #3965577 manifolds were nearly identical except for one feature: the 69 manifold had the carb pre-heat holes and groove on the forward part of the carb flange; the 70 manifold deleted this provision.

For the 1969 manifold to have been originally used on your application would have required that the 1969 gasket and stainless steel baffle also be used between the carb and the manifold. The 1970 gasket did not have the cut-out for the heat groove and NO stainless steel baffle was required or used.

One other thing to check for: the factory could have "converted" the '184' manifold to the '577' manifold configuration by plugging the holes in the intake manifold heat groove ends. In fact, I recommend that all 69 and prior manifolds with this provision be so-modified. But, the factory could have done the same thing, too. I really don't think that the factory would have used a 1969 configured manifold on a 1970 engine; too many other factors come into play to complicate things. However, they could have converted the 1969 manifold to the 1970 configuration as I described above. Then, the manifold would have been functionally equivalent to the 1970 manifold and all other 1970 parts could have been used.

I'd recommend checking your carb heat groove end holes for signs of modification. Of course, the mods, if present, could have occurred later. But, I'd strongly suspect that such mods, if present, were made at the engine plant.

[Bill W.]

Re: Intake Manifold

Lee I dont know about a 69 intakes but my 70.350/350 #2650 has a 3965577 ...A/20/0 intake ...A/17/0 block..704207.da ...3529 carb. It was built feb 5 70 and has a 69 rt door on it and had never been damaged before I owned it. Bill..

[Clem Z.]

Re: Intake Manifold

the NHRA spec sheet which is supplied to them by GM list 3965577 manifold for 1970 350/350 but it also lists a 3886677 as a alternate 1970 350/350 manifold. just posting this for your info.