7 1/4" info
My 7 1/4 held up behind my stock 340 with a four speed in my 65 Cuda with street tires. But after saying that it sure didn't like a set of slicks, never did a single run in it with the slicks. I now have a 8 3/4 with yukon axles. :toothy7:
Going from 2:76 to 3:55's man did I feel the difference.
I tried to find a spool for you in the cataloges at the shop here and no spool,s although we don't have a great selection of brands!
If you have an auto it should hold up, but why not just step up to an 8 1/4 and make sure, you can get one cheap from a wrecker!