66 L79 Pulley Question

[Michael H.]

Re: 66 L79 Pulley Question

Todd, Check out this picture that was posted a few days ago. This is a 1966 L-79 and clearly shows two groove pulleys and the location of the dedicated water pump/crankshaft non adjustable belt.

To add a bit more confusion...... IF the parts books are accurate, the alternator pulley used for a 66-67 350 HP without power steering is a 3871242. This is a thick machined pulley that moves the belt groove about one track further forward than most conventional pulleys. (the same fat pulley used for 65 with FI) If that's the case, the idler belt would automatically be forced to the rear track and the alt belt to the front. This is the correct pulley according to a 66 and 73 printing of the parts book.
Unfortunately, there isn't a parts list for L79/350 HP included in the 66 AIM that would give us the assembly line part number.

If power steering is added to the L79, the parts book calls for pulley part number 3829387, a thinner pulley than the 3871242 that would place the alternator belt in the rear groove of the water pump/crankshaft pulley grooves.

I don't think the research is complete on this issue.

[Brian K.]

Re: 66 L79 Pulley Question

In my research I found the upper alternator bracket is different on 66 with L79 and power steering. The power steering upper bracket is 386882 which I think explains the different alternator pulleys.

To add a bit more confusion...... IF the parts books are accurate, the alternator pulley used for a 66-67 350 HP without power steering is a 3871242. This is a thick machined pulley that moves the belt groove about one track further forward than most conventional pulleys. (the same fat pulley used for 65 with FI) If that's the case, the idler belt would automatically be forced to the rear track and the alt belt to the front. This is the correct pulley according to a 66 and 73 printing of the parts book.
Unfortunately, there isn't a parts list for L79/350 HP included in the 66 AIM that would give us the assembly line part number.

If power steering is added to the L79, the parts book calls for pulley part number 3829387, a thinner pulley than the 3871242 that would place the alternator belt in the rear groove of the water pump/crankshaft pulley grooves.

I don't think the research is complete on this issue.

[Michael H.]

Re: 66 L79 Pulley Question

In my research I found the upper alternator bracket is different on 66 with L79 and power steering. The power steering upper bracket is 386882 which I think explains the different alternator pulleys.

The alternator adjusting brace may be different for cars with power steering but the fore/aft position of the alternator remains the same because I think it bolts directly to the exhaust manifold.