Re: 12 bolt vs 10 bolt
My frined has a 10 bolt with 3.73s in his 69 firechcken with a farily hot for street 469 .060 ove 455 poncho running low 12's with 4spd so it gets hit hard sometimes.
Car has been on the road every yr for car shows/ cruising & occassional pounding since 1990-91 and he doesnt babby it either getting into it often ,car also see's the strip a few times a yr sometimes with borrowed slicks too .
That 10" rear has held up well for many yrs behind his 469 man trans setup that has been est to have a conservative 450-475hp/540-550lbs trq with the motor setup it has (Perf cam/ram air heads with mild porting/10.5 compression/edel trq'r intake/rac prepped 1050 dominator carb/roller rockers/motor ballanced/headers) and also from the times it runs which is low 12's.
So a 10 bolt has to be farily strong to take that abuse for that long but my friend takes the attitude it wont last forever. He has been surprised that the 10 bolt has lasted as long as it has getting abused fairly often with a decent amount of hp/trq from a 469 poncho.
Nunless your putting a real animal motor in front of it and dont plant to abuse the heack out if a 10 bolt you can get good service life out of them in a semi perf application so go for it if thats what you currently have. But if you have to buy a rear then i would spend the additonal $ for a 12 bolt while your at it.
1969 CHEVELLE SS396,ORIGINAL #'S MATCH,GOT IN 1978,(In 2001 rblt/bored original 396 .030 to 402)/M20/12BOLT/3:31'S
2002 MAXIMA (DAILY DRIVER/1 owner,GOT 3/2013 w-44k miles)
2009 HD ELECTRAGLIDE CLASSIC ULTRA (GOT 11/14 W-9,700 miles)