Find another Alternator Shop! I just went through this with power steering to boot on a 250. For the 250, there at least 4 different dampeners and I don't know how many water pump/fan pullys, but only 4 alternator pullys, 3L, 4L, dual groove and grooved flat belt. There is ONLY ONE alternator mounting bracket! It took me two months of haunting salvage yards and ebay to come up with a complete set of pullys, brackets and hardware! My set came off of a 1970 Buick engine that had been pulled to install a V-8. The owner was in a giving mood and I got all the stuff I needed for a six pack! I used a 2 foot piece of 1/4 round and layed it in the grooves to check line up. Keep at it, you'll get it!
best wishes,
Les
