Thread: Got a 478...
View Single Post
  #32  
Old March 25th, 2023, 04:52 PM
Prowbar Prowbar is offline
Senior Member
 
Join Date: Dec 2020
Location: Friesland, the Netherlands
Truck: 1965 GMC 1500, 478 V6, SM420
Posts: 386
Rep Power: 183
Prowbar is a jewel in the roughProwbar is a jewel in the roughProwbar is a jewel in the roughProwbar is a jewel in the roughProwbar is a jewel in the roughProwbar is a jewel in the rough
Default Re: Got a 478...

Another piece of the puzzle is the front pulley. I wrote about this in the 65 GMC build thread: I wanted to originally use the 478 pulley. However, it looks out of place, and it didn't fit after all. You would end up with an overdriven water pump as well.

Therefore modification of the 305 pulley is in order. I designed an adapter plate that can be used to bolt on external weights. It mounts onto the bolts holding the pulley in place, and nuts are used to fixture it. I am also working on a balancing fixture to determine the exact weight needed. The 478 pulley serves as a guide here.

Another 'upgrade' that I'm doing to the 305 pulley is the addition of the tapered sleeve, found in the bigger pulleys. This is a copper sleeve, that tightens onto the crankshaft when the front crankshaft bolt is tightened. It is easily added to the 305 pulley by machining a 15-degree taper into the bore.

More to follow.
Attached Images
File Type: jpg 20230325_155446.jpg (3.15 MB, Multiple views, 1 clicks)
File Type: jpg 20230325_155451.jpg (3.02 MB, Multiple views, 1 clicks)
File Type: jpg 20230325_155502.jpg (3.93 MB, Multiple views, 1 clicks)
Reply With Quote