An overdrive for a Chevy pickup

April 1, 2008 | By Staff


My current project is a 1972 C10 Chevy pickup truck with a 250 cid inline six cylinder engine and Turbo 350 automatic transmission. Will any of the current auto salvage yard overdrive transmissions bolt right up to my engine?


You should be able to bolt a newer overdrive automatic that originally came in a Chevrolet to your truck’s engine.

But there are a lot of variables here so the entire installation will almost certainly not be a simple bolt-in operation for your truck.

The Turbo 350 main case measures 215⁄8 inches and the tail housing measures either 6, 9 or 12 inches, making the total length of a Turbo 350 either 275⁄8 inches, 305⁄8 inches or 335⁄8 inches.

The 700 R4 main case measures 24 inches and the tail housing is 6 inches for a total length of 30 inches. The 4L80E transmission has a 261⁄2 inch main case and 6 inch tail for a total lengthof321⁄2 inches.

So, while a salvage yard transmission will probably bolt to your engine, it will most likely be a little bit longer or a little bit shorter, and its rear mount will almost certainly be a little bit too far forward or a little bit too far rearward.

This means you’ll have to alter the length of the driveshaft and modify the cross member or mount bracket where that rear mount attaches.