71 BB smog pump bracket cast # ??

[Sheldon S.]

I have a 71 Big Block and need the smog equipment. I have found a bracket for the pump that has a casting number of 3877644 on it and am wondering if this is a part number or if this is correct for my application. Thanks in advance. Sheldon

[Dick W.]

Re: 71 BB smog pump bracket cast # ??

The P&A calls for a 3919890 bracket. The judging manual calls for it to be a stamped steel bracket, unlike the small blocks which were cast. Joe Lucia may be able to shed more light on the part

[Joe L.]

Re: 71 BB smog pump bracket cast # ??

Sheldon-----

All 1971 Corvette big blocks used a stamped steel AIR pump bracket; none used a cast iron bracket. The GM #3877644 was used on 1966 full size Chevrolet passenger cars with big block and K-19.

[Mike H.]

Re: 71 BB smog pump bracket cast # ??

Sheldon,
I hope you are aware that the LS5 did not have the smog equipment in '71. The LS6, on the other hand, did.

[Joe L.]

Re: 71 BB smog pump bracket cast # ??

Mike-----

Yes, that's absolutely correct. I should have caught that, too. 1971 with LS-5 did NOT use the air injection reactor (AIR) system, at all. So, that would eliminate the need for any AIR system components if one has a 1971 LS-5. 1972 with LS-5 DID use the AIR system, but 70-71 LS-5 did not.

[Sheldon S.]

Re: 71 BB smog pump bracket cast # ??

Joe,

My car has an engine stamp of CPJ designating 365HP Auto and a build date of April 29, 1971. I have found the ECS mounted on the left side of the car in the fenderwell area, which i thought was part of the AIR system. Or was this part of the a Calf. car on its own. The other thing is that the right side exhaust manifold is drilled and tapped for the exhaust manifold tubes but the left side is not. The car appears to be original and has not been restored. I was told it came from Calf. but am still tracing the history. Would they have used the drilled and tapped manifold on a non AIR car? Any comments appreciated.
Thanks Sheldon

[Joe L.]

Re: 71 BB smog pump bracket cast # ??

Sheldon----

I think that you are referring to EEC (evaporative emissions control). This is the system utilizes the cannister mounted in the driver's side front fender well area. For 1971, ALL Corvettes received this system, regardless of where delivered. It was part of what was referred to as CEC (combined emissions control system). There was no difference between California-delivered Corvettes and all other Corvettes for the 1971 model year.

As far as the manifold goes, it's quite simple. The manifold with the AIR fittings was added to the car at some point. For quite a few years, GM supplied only the manifolds with AIR fitttings to SERVICE all 1965-74 Corvette applications. So, if for any reason you needed one and you went to your Chevrolet dealer to get one, you got one with AIR fittings whther you needed that feature, or not. It's also possible that the original manifold was replaced with a used manifold that had AIR fittings. Regardless of how it happened, the manifold with the AIR fittings was likely not with the car when it was delivered. A check of the casting date on it will probably confirm that.