I am going to pick up a rear end tomorrow and he has 8's and 9's. I have a sixty six but he wasn't too specific with years. he has several. Any advice?
thanks!

 

9's are practically bullet-proof, so if your building a beast, definitly go with one of those

if your just doing a mild-moderate built, a 9" might be alittle overkill and would go with the lighter and cheaper 8"

im not sure of the measurements of the earlier models, but 67-70 rear ends are 59.25" from axle face to axle face with a 43" spring perch span...the 66 rearend is a few inches narrower

 

Can the length be modified?

 

yeah, you can have a shop cut the housing down to the right lenth, or you could do it yourself if you know what your doing.

 

It would be easier to have one that is already the correct length, but yes, you can shorten the overall width. I'd carefully compare the prices though (unit price+ modifications+ etc etc.. vs correct unit). U'll need a shop to do it...

 

Unless you're building a 400+ hp barn burner, just get an 8" that's the correct width for your 66.