427/390h/p intake

[William G.]

What is the part number for a 427/390h/p and what is the carburetor used
what is the 3957994 number used on, is this number after market
thanks for looking

[Douglas L.]

Re: 427/390h/p intake

As far as I know there were 3 intake manifolds used on the L36 engines in the 68-69 era. First was 3919849 in late 67 early 68 then 3937793 mid to late 68(identical the 849 except for screw in rather than press in bypass hose nipple) and finally 3947801 in 69(essentially identical to 793 with a change to the choke stove mounting area). All were aluminum, oval port and relatively low-rise.
Carburetor wise, in 68 it was 7028209 with a 4 speed and 7028216 with a th400. In 69 it was 7029215 for a 4 speed and 7029214 for a th400, all 4MV Q-jets.
Can't help you with the 3957994 manifold, quick search shows cast iron BB intake manifold but no idea of the application. Doug

[Joe L.]

Re: 427/390h/p intake

What is the part number for a 427/390h/p and what is the carburetor used
what is the 3957994 number used on, is this number after market
thanks for looking

William------


GM #3957994 was the PART NUMBER for the manifold with casting number GM #3947801. This manifold was used for 1969 Corvettes with L-36. It is a very low rise, aluminum manifold with spread bore (Q-Jet) carb flange. It also became SERVICE for 1968 Corvettes with L-36 which were originally equipped with manifold GM PART NUMBER 3928457 which carried casting numbers GM #3919849 or 3937793. All of these manifolds are configured very similarly, virtually indistinguishable except for casting number.

These manifolds were Corvette-only and never used on any other Chevrolet application. They were the only big block PRODUCTION aluminum manifolds EVER with a spread bore carb flange.

What carb was used with the GM #3957994 (cast 3947801) manifold? With 4 speed it was Q-Jet GM #7029215. With THM-400 it was Q-Jet GM #7029204. However, many Q-Jets will work with this manifold.

[Tom D.]

Re: 427/390h/p intake

The 3937793 has a funky little TAB immediately behind the choke coil well. (The tab or "wall" is perpendicular to the driveshaft.) Perhaps 3/4" high it looks like a barrier to hold heat in the area, instead of letting the air flow right over the choke bi-metal coil. I will see if I can find a photo. In the meantime if you have access, See Alan Colvin's 1965-1969 Chevrolet By The Numbers book, page 175.

Anyone think the little square tab is for something else?

BTW, Paragon sells several choke coil kits, but 1709K is the only one that fits this aluminum "low rise" Rochester Quadra-Jet (Q-jet) manifold.

ken thomas intake 3937793 - 1.jpg