The 1947 - Present Chevrolet & GMC Truck Message Board Network - View Single Post - what pulleys for 250 -w- air?

RichardJ · 01-02-2019, 04:08 PM

>>I currently have a electronic module in my diet in <<
What does that mean?

The body/housing of the external coil HEI distributor looks the same as the regular HEI, but the index notch for the cap is in a different location.
I addition to the trucks, the HEI with short cap and external coil was used in '75-'76, X-body Chevy Nova, Buick Apollo, Oldsmobile Omega and Pontiac Ventura with the 250 engine.
A word of caution. I pulled a HEI out of a Olds or Buick and I don't know which, that had a smaller diameter on the lower part of the shaft. When installed in my 292 the distributor wobbled. I thought the shaft was bent and didn't see the step on the shaft until the gear was pulled off. These engines have a brass bushing in the engine block just above the oil pump. You could switch bushings, but easier to switch out another 6 cyl HEI shaft.

>>Noticed you went from a 250 to a 292.<<
Not sure what you mean. My truck was born with a 292. I modified a X-Body 250 PS bracket for use on my 292.

My AC system has been in operation for 12 years. I never bothered looking for a 3-groove pulley. The extra, single groove, outer crank pulley bolts directly to the harmonic balancer inner hub. It has the advantage of trapping the harmonic balancer outer ring in the event it should come loose.

As I mentioned in my post from two years ago, the Vintage Air drawing is wrong. The outside crank pulley diameter is smaller and will not work. The two belt speeds on the Alt would be different.

01-02-2019, 04:08 PM	#12
RichardJ Registered User Join Date: Apr 2010 Location: So Cal Posts: 1,489	Re: what pulleys for 250 -w- air? >>I currently have a electronic module in my diet in << What does that mean? The body/housing of the external coil HEI distributor looks the same as the regular HEI, but the index notch for the cap is in a different location. I addition to the trucks, the HEI with short cap and external coil was used in '75-'76, X-body Chevy Nova, Buick Apollo, Oldsmobile Omega and Pontiac Ventura with the 250 engine. A word of caution. I pulled a HEI out of a Olds or Buick and I don't know which, that had a smaller diameter on the lower part of the shaft. When installed in my 292 the distributor wobbled. I thought the shaft was bent and didn't see the step on the shaft until the gear was pulled off. These engines have a brass bushing in the engine block just above the oil pump. You could switch bushings, but easier to switch out another 6 cyl HEI shaft. >>Noticed you went from a 250 to a 292.<< Not sure what you mean. My truck was born with a 292. I modified a X-Body 250 PS bracket for use on my 292. My AC system has been in operation for 12 years. I never bothered looking for a 3-groove pulley. The extra, single groove, outer crank pulley bolts directly to the harmonic balancer inner hub. It has the advantage of trapping the harmonic balancer outer ring in the event it should come loose. As I mentioned in my post from two years ago, the Vintage Air drawing is wrong. The outside crank pulley diameter is smaller and will not work. The two belt speeds on the Alt would be different. Attached Images __________________ '67 GMC 2500, 292, 4spd, AC Last edited by RichardJ; 01-02-2019 at 08:17 PM.