1962 GMC 478M V6 Swap

[Rezzato]

I thought i might post this swap as it is pretty unique. I have a 1962 GMC 1000 that had a 305 V6 in it. It got me interested in these V6 engines and I discovered there were many more offered in various displacements. I wanted a larger V6, so i found a 478 Magnum on craigslist that I am getting ready to put in. The block will bolt right in but changes need to be made with the flywheel and bellhousing.

The 478 comes with a heavy duty truck bell housing that houses a massive flywheel, clutch, and pressure plate. This bellhousing is too large to fit into my 1962 GMC 1000 and I will need to replace it with the light duty bellhousing found on the original 305.

Unfortunately the 478's flywheel will not fit in the light duty bellhousing and needs to be replaced. The problem is that the 478 is externally balanced using its flywheel as a ballancer. This flywheel also has an eight mounting holes unlike its other V6 counterparts which use 6 bolts.

Only a custom made flywheel or a flywheel from a 379 V6 will work. The 379's flywheel also has an eight bolt pattern, is externally balanced, and will fit within the light duty bellhousing. Fortunately I have a 379 sitting around that I bought a few months ago. This is an extremely rare engine only found in 1973,1974 in 6000 series trucks.

I need to get the 379's flywheel drilled and tapped to receive the smaller pressure plate found in the light duty trucks.

Next I need to have the light duty bellhousing bored out a bit to accept the larger input shaft retainer of the SM465 I will be using.

Edited by staff

Here is the truck


Here is the 478 Magnum, notice the air compressor on the right.


I will have many more photos tomorrow of all the parts.