Need info on *correct* 1956 1x4 manifold

[Alexander C.]

I currently have an incorrectly dated intake manifold for my 1x4 1956 car. I am stepping up the search for a *correct* one.

I know the GM casting number is 3735448. The date code I have now is G 56. Note the space between the G and the 56. I have been told that Corvette 3735448 manifold casting dates have no spaces and that passenger car 3735448 manifolds have the space. Can somoene please confirm if this is the case, or that I'm backwards, etc? Just to confirm, G 56 is July 1956 right?

Also, which would the intake manofild date be closest to, the date on my heads or block? Or would it be dated btween a couple of them, or?

Thanks! Alex

[Jack H.]

Re: Need info on *correct* 1956 1x4 manifold

Per your copy of the 56-57 Judging Guide, the date code convention for cast iron intake manifolds is the same as that used on the engine block. Those who say you have a 'passenger car' intake are kinda/sorta right, but not fully.

Back then, there were two casting foundries (Saginaw and Tonawanda) and they differed in terms of exact casting configuration. Saginaw (who supplied the Flint engine plant) used a single digit year code. Tonawanda used a 2-digit year code. BOTH supplied Chevy passenger car/truck final assy plants.

But, the Corvette plant in St. Louis, sourced almost exclusively from Saginaw/Flint for SB engines. This was probably a freight-in cost consideration...

As far as how the date on the intake casting should compare to the date(s) on the block and cylinder heads, it's simple. At the engine plant, they pulled raw castings from inventory at random. We expect all to precede the engine's stamp pad date and all to fall within a 0-6 month window prior to the cars' final assy date (based on VIN).

[Edward M.]

Re: Need info on *correct* 1956 1x4 manifold

Alex;

There is no difference between a passenger car (Flint casting) and a Corvette single four barrel intake.

The intake you have is a Flint casting. G 5 6 (regardless of spacing) is July 5th, 1956. A Tonowanda casting wouild be G 5 56.

The intake manifold casting date should be pretty close to both your heads and your block, which also should be pretty close to each other.

What date codes are on your block and your heads?

I seem to recall that your block is a June 5, 1956 Flint block. Is that correct?

Also, the casting number may not be 3735448. It may be 3837109. It will depend on the date. The transition from the 109 to the 448 occurred in late June, early July of 56. Some overlap with the 109 may have occurred.

[Edward M.]

Re: Need info on *correct* 1956 1x4 manifold

One more thing Alex;

Many years ago I did an article for The Restorer about 1956 single four barrel intake manifolds.

As part of that article, I offered a $25 reward for the person that sent me a picture of the earliest dated 3735448 intake. The winner had a manifold dated G 6 6.

You are now the "winner" with a manifold dated G 5 6. Sorry, no $25 reward any more.