I think I can come "close enough" on my new belt length requirement, but does anyone have a length they can throw at me any way? Engine is a '91 no A/C (and now no smog pump).

Alternator is currently stock 2G with plans to go 3G. I know this doesn't make a significant difference, but I'm thinking the 3G may require a little more length - yes, no, maybe? Just want to allow for that and not require another new belt when I go 3G.

 

On my '92 4.9 I used a 78.5" belt when I removed the smog pump and A/C Compressor.

 

Thanks, I was thinking I needed one about 80" - that might have been a tick too long.

 

Thats the length that Ive heard before, I got an 87 4.9L with no A/C and I plan to upgrade to a 3G and take out the smog pump, its already disconnected its just there

 

Well, I picked up a 78.5" belt tonight and it's a bit too short. Even tried a smaller idler bearing that I had around and I still couldn't get the belt on. I do still have the 2G - does upgrading to the 3G perhaps move the pulley inboard a bit, shortening the required belt length?

Regardless, I'm going to try to get a 79.5 or 80".

 

Hmm, I replaced my tensioner a little while back, and the pulley that was on the new one was quite a bit smaller than the old one, so that may explain the belt length differences.

 

I had a smaller idler bearing around and tried that - still couldn't get the belt to reach around the pulley (and I tried a couple different ways).

One thing I noticed late tonight though is that the alternator bracket got some sort of revision in '92, judging by the "F2" part number. Perhaps the F2 bracket positions the alternator outbound a bit more? Total speculation at this point - I'll report back.

The only thing I can report is that the 80" belt I picked up today works perfectly fine.