rrubel's question made me look. I relayed what I was told by the 'old head' who rebuilt my Super T-10. The spec sheet, posted elsewhere here, shows 205hp and 290 lb-ft. for the '84.
The guy who rebuilt my box has been building Chevy trannies for 15+ years and is well reputed here. I did not question his statement, that the stock box was good for 225 lb-ft, and that changing to the only gear set available, would bump it to 325. I was not interested in a tranny change project, atop the 2 years restoration/ performance bump already 'enjoyed'. Also, I had dropped some coin on the renewed O/D.
We changed all the gears ratios, due to my 3.73 rear end, which had forced me to shift quickly when accelerating. With the warmed up, but stock 350, the 'show' was over quickly, with the flat, but low-peaking torque of my old engine. I did not like the new gears, versus the 3.08s of the Z-51 package, even if the car was quicker off the line.
Now, this very hot 406 revs lots higher with its '90 speed density port injection, etc., and the rear ratio is less of an issue.
BTW, my 406 cost $4756, with lots of 'good stuff' inside. While my engine was not dynoed, the shop has specs on a similar motor; both numbers well over 500. My larger displacement, roller cam, head upgrade, etc, adds to those numbers, and the car underscores their ratings.
This $$ is lots less than the ZZ4, LT-4, LS-1 or other Chevy alternatives, which demanded the same fuel delivery mods, etc. Every time I had decided on a crate motor option, Chevy changed the availability! Many of these crates, would not bolt up to my tranny, either, which I tried to avoid. I am one of 10 people who actually like the T-10/DougNash package!
I hope the actual ratings on my tranny are higher, so I can avoid that change. I saw the wear- through in the case hardening on the stock gears and the many cracks on most of the teeth in second, first and third gears. All this from a slightly warmed up '84 350, running AMSOIL synthetic tranny gear lube, since day one! Not impressive, GM!
The overdive was fine, and I was assured by Paul, at Gear Zone in Boca Raton, that the redone O/D would take all this power and more. He did all the units for Callaway and started rebuilding them at day one.
Doing it again, I'd start with an '86 or later, and NOT buy from Lingenfelter!