I have a stock Th200c in my 82 TA that is shot and was wanting to swap it out for either a Turbo350 or a 700R4, it will be a daily driver with quite a bit of highway miles, the occasional race and will eventually be bolted up to a Chevy 350 and I was wanting to know is which would be best and won't make my wallet too light. Also thinking of swapping out the rear end, it has a 2.73 posi (I think it's posi, when it's in the air if you turn one wheel the other turns in the opposite direction.) but I've been offered a 3.42 and not sure if it's posi. What would be the best combination? I'd appreciate any help. Thanks.

 

That's the classic description of a non-posi rear, but the only way to know for sure is to take the cover off and look.

I'd go with a 700R4 if you're going to be on the highway.

 

I have had both th350 and 700r4 in my '82-th350
(out of an'80 z28)was a virtual bolt in using a torque
arm kit.The th350 was in from 1993-95,then i decided
to reactivate the A/C and didn't want the A/C pump
running at over 3000rpm for long periods of time,so
got a 700r4 out of an '85 caprice for $150,clapped a
shift kit in it along with a f-bod tail housing and installed
into my '82 using '83 up driveshaft,torque arm,shift,
x-member,speedo cable,ETC.As i recall,two holes in
the '83 x-member matched the '82 frame rails while i
had to add two more holes for the rear holes in the
x-member.Though i did not like the 1-2 ratio spread
in the 700r4 as well as the spread in the th350,the
overdrive is nice(did not affect milage that much VS
the 350) I like 3.42s with my 700r4,while 3.23s
were my faves for all around use with the th350-the
3.42s seemed a touch "busy"at 75 mph +