74 Smog

[Robert S.]

Smog info and parts wanted for a 74 4-speed. pump plate #7801149.
Does 74 pump has a unique part # or is it interchangable with other years.
Thanks in advance for any info. Bill Hodel contact info also wanted.

[William C.]

Re: 74 Smog

Try 216 832 0871, or 330-832 0871 if that doesn't work. (Massillon Ohio) I believe he runs an ad in the "Driveline)

[Joe L.]

Re: 74 Smog

Smog info and parts wanted for a 74 4-speed. pump plate #7801149.
Does 74 pump has a unique part # or is it interchangable with other years.
Thanks in advance for any info. Bill Hodel contact info also wanted.

Robert------


The 1974 AIR pump ASSEMBLY, GM #7803948, was not unique to 1974. It was used for L1971-74. The 1974 pump configuration is the same as all 1969-75, except 1969 with L-88/ZL-1.

[Robert S.]

Re: 74 Smog

Thanks Joe. Is an ac delco #7843606 (nos) correct for a 74? Thanks.

[Joe L.]

Re: 74 Smog

Thanks Joe. Is an ac delco #7843606 (nos) correct for a 74? Thanks.

Robert-----


No; it was never used for any Corvette application. From what I can tell, it was used for some early-to-mid 80's truck applications.

[Robert S.]

Re: 74 Smog

chevy parts book 786686 (up to 71) 7817809 (72-75) explain please. Corvette different #?
also should it have a white fan? correct date for max points? my car built nov 73. thanks.

[Joe L.]

Re: 74 Smog

chevy parts book 786686 (up to 71) 7817809 (72-75) explain please. Corvette different #?
also should it have a white fan? correct date for max points? my car built nov 73. thanks.

Robert-----


GM #7806686, cataloged for 1968-71 applications was actually a 68 style pump with external relief valve. It is a SERVICE-only pump for 1969-71 applications. It's not even the original pump used for 1968 applications, although it's configured like the 1968 pump (and 1969 L-88/ZL-1 pump).

GM #7817909 is a 1976-78 style pump. It is SERVICE-only for 1972-75 Corvettes.

The original GM #7803948 pump used for 1971-74 applications was once available in SERVICE but was discontinued and replaced by the 7817909 a long time ago. The 7817909 is NOT configured like the original pump.

[Robert S.]

Re: 74 Smog

Thanks Joe for your knowledge. I guess I need to get a dated used pump and have it rebuilt for max points? does it have a white gear?

[Joe L.]

Re: 74 Smog

Thanks Joe for your knowledge. I guess I need to get a dated used pump and have it rebuilt for max points? does it have a white gear?

Robert-----


Originals had a white centrifugal filter ("fan").

[Terry M.]

Re: 74 Smog

The black "fan" (actually a centrifugal filter) on the AIR pump began during the 1972 model year. Thus a 1974 should have a black filter.

[Joe L.]

Re: 74 Smog

The black "fan" (actually a centrifugal filter) on the AIR pump began during the 1972 model year. Thus a 1974 should have a black filter.

Terry----

OK, I thought it started for 1975, but I've never really paid a lot of attention to this.

[Terry M.]

Re: 74 Smog

From the 1970-72 TIM&JG: "The centrifugal filter, mounted at the front of the pump, was white opaque plastic until early model 1972s. Then a black plastic filter was next with fins that are square at the front. Fins that are rounded at the front have been reported on very late 1972s, but in general, these are indicative of a service replacement filter."

[Harmon C.]

Re: 74 Smog

The fins on a 73-74 are black and cut off at a 45 degree angle.

[Jeff A.]

Re: 74 Smog

What date do you need? I have quite a few 1974 pumps collected over the years. Loads of other years also...
All the 74 pumps have black fans.