Dumb question about serp. belt

[ComfortablyNumb]

I measured my belt while it was on th car, I just sort of ran the string over the pulleys and belt while it was on there. The string is 90", isnt that kind of big? I also went to the NAPA website to get a number for a pulley and I have 2 options, serp belt for auto and serp belt for Manual trans. My car was originally equipped with a manual but has since been converted to AOD, so which should I get? Sorry for the stupid question, Thanks. Its an 87 5.0 with All accessories.
-Skip

 

[50Dreamer]

I dont really think there is any diffrence at all. I dont see how there could be.

Dave

 

[TIMMY2734]

There is no difference between autos and manuals. You prob got mixed up with AC and no AC

 

[Fairlane]

It could have been with a smog pump or without a smog pump. This might help.

 

[rd]

I measured my belt while it was on th car, I just sort of ran the string over the pulleys and belt while it was on there. The string is 90", isnt that kind of big? I also went to the NAPA website to get a number for a pulley and I have 2 options, serp belt for auto and serp belt for Manual trans. My car was originally equipped with a manual but has since been converted to AOD, so which should I get? Sorry for the stupid question, Thanks. Its an 87 5.0 with All accessories.
-Skip

Stock belt length on a 79 5.0 is 93.5 inches. I think newer ones are a bit shorter because the AC pulley is smaller.

It is easy to check the catalog data for lenght at the parts store.

Sometimes the best fit varies by 1/2 in or so between cars. If you have removed accessories, all bets are off, you have to measure and experiment.