My 64 El Camino currently has a 10 bolt 3.08 positrac rearend. When it finally hits the road again, it will have a relatively mild 350 (Maybe 325 hp) with a Comp Cam, Edelbrock dual quads and Hedman Elite headers. The trans is a Muncie M20. I don't intend to do any heavy-duty racing or anything like that. Just a nice cruiser. But I am wondering about that 10 bolt rearend. How well do they hold up to mild, once-in-a-while punishment? You know, the occasional burnout and such. This is the first vehicle I've had with a 10 bolt and it makes me wonder. Any advice or suggestions are appreciated.

it should be fine,
i had a 67-ElCo with a 3.08-posi as a teenager and it held up to some(lots) of abuse. :)

you are not going to hurt that 10 bolt with a mild 350 and street tires..have fun and save your money :thumbsup:

The ten will be fine! If you ever go for the 12 I would be interested in the 10 bolt posi:D

Thanks for the feedback, guys. I was thinking it would be okay but I always like a little reinforcement. This car has been sitting for a long time. I intend to drain the lube and am wondering about using some synthetic rear end lube, Royal Purple or some such. What does everyone (anyone?) think about using synthetics over mineral lubricants?

I wouldn't use synthetic with an old carrier..thats just me.
Just some conventional 85W/140 and call it a day

Make sure whatever you replace the current lube with that you add the Limited Slip Additive whether it be GM or some other brand.Trust me you dont want to hear or feel the result of not adding the stuff.

Regular lube and the GM additive for the posi clutches should be all it needs, unless you want to swap in some 3.73 gears in it.