So just posting in the event it helps someone later. I bought the Metco 100mm snub, 1-90mm, and 2-100mm aux pulley set. I have a 3" sc pulley, and stock crank pulley. When doing the Metco math, you come to 76.5" with their set and with a 3" sc pulley and stock crank pulley. And doing some searching here, I found a thread of someone with a similar setup (2.9" sc pulley) that chose to use a 75.5".
I decided to reinstall the old 74.5" that was on the car before the pulley swap just to see if I could, and to see where the tensioner gauge fell. It went on, though a little tight (obviously). The tensioner wasn't completely extended down, but the marker was at the right edge of the little raised tension gauge. I also used a string to measure how much slack the tensioner will pull in from all the way down to all the way up and it comes in around ~2" so I decided to get a 75.5".
For whatever reason, LMR doesn't carry a Gates 75.5" but rather a 75.65" so that's what I got. CobraBob's old (original) belt page actually listed 75.5" for my config, and in my opinion, is the better route to go instead of the Metco measurements. I think their 76.5" recommendation would work, but the tensioner will be close(r) to maxing up. I would say somewhere between 75.5" or 76" is ideal.
Here she is at 75.65" with no miles or heat on her yet. I figure after a nice hot engine and some strong pulls, she'll relax a bit more and be pretty close to center.
I decided to reinstall the old 74.5" that was on the car before the pulley swap just to see if I could, and to see where the tensioner gauge fell. It went on, though a little tight (obviously). The tensioner wasn't completely extended down, but the marker was at the right edge of the little raised tension gauge. I also used a string to measure how much slack the tensioner will pull in from all the way down to all the way up and it comes in around ~2" so I decided to get a 75.5".
For whatever reason, LMR doesn't carry a Gates 75.5" but rather a 75.65" so that's what I got. CobraBob's old (original) belt page actually listed 75.5" for my config, and in my opinion, is the better route to go instead of the Metco measurements. I think their 76.5" recommendation would work, but the tensioner will be close(r) to maxing up. I would say somewhere between 75.5" or 76" is ideal.
Here she is at 75.65" with no miles or heat on her yet. I figure after a nice hot engine and some strong pulls, she'll relax a bit more and be pretty close to center.
