Hi all, I'm putting a 351w in place of my 302 in a 79 F100. After bolting the 302's pulleys on the 351w the crankshaft pulley sticks out further than the alt and water pump pulleys a little more than a 1/16 inch. Not alot but noticeable. I'm worried about throwing the belts off. Both balancers are exactly the same. Measuring from the end of the crankshaft back to the timing chain sprocket there's .073 in. difference. The 302 having the larger dimension of the two which puts the balancer and pulley closer to the engine. Has anyone had this problem? I'm thinking of milling .073 off the back of the balancer. Any advice would be GREATLY appreciated. Dave

 

Are you certain that the belt groove centerline is actually out of alignment and it's not just that one pulley has more metal on the non-critical outer or inner area?
Can't you just use the 351W pulley(s) instead of the 302 unit(s)?

 

I just checked the centerline with a straightedge and it's definitely off. I didn't have pulleys for the 351, I thought the pulleys for the 302 and 351w were interchangeable. Thanks

 

Some pulleys will be interchangeable if they are from similar years. I suppose yours don't fall into that category.

I think an easier fix than machining parts would be to get some sixteenth inch thick, or .073" thick aluminum or other sheet metal and cut spacers to shim out the alternator pulley and water pump pulley. The layout of holes on these spacers does not really need to be that precise, as the alignment of the pulleys is still determined by the close fit on the shafts.

 

Sounds like a plan. Thanks again.