You know something? It is certainly true about being able to learn something new every day, if you just look for it. In the case of this thread, I knew the "regular" C6 would not bolt to a small block engine - or I may have known it and totally forgot about that. But, until today I never knew there was a small block C6, but it makes sense that they are out there, for trucks using a 302 or 351W engine if no other reason. I think had I know of the small block C6 I might have gotten one of those with a Gear Vendors OD unit, despite the added cost in comparison to getting the AOD tranny, just to get the strength out of the C6 and GV units if nothing else. I have not heard that the AODs are wimps when it comes to how much horsepower they can handle, but definitely like the C4 they haver some limits. What I found re: how much power those can handle includes:
"C4 trannys are rated at 450 ft/ lbs. AOD rated at 506 ft/lbs. In race ready form either can handle up to 800ft/lbs and 1200 HP"
The 351W (not C) in our 73 Mach 1 clocked in at 360 HP on a dyno run after the engine was rebuilt, a moderately powerful street/strip engine running with only 9.5:1 forged aluminum pistons in order to handle the lower octane ethanol free gasoline in our area. The HP rating was told to me by the prior owner, and he did not tell me the torque level. Bu, I did do a chassis dyno run on the Mach 1 about 3 years ago. in comparing the chassis HP to the crankshaft HP, then applying the ratio to the torque level, the built 351W would have about 400 LbFt on a fairly flat and wide band of both HP and torque. If that is close to accurate, it is easy to see why the C4 began to slip so badly after a bevy of Wide Open Throttle 1-2 upshift, where there was enough torque to cause the rear tires to fairly significantly break traction at speed. The AOD is rated for a little more torque than the C4, but you can believe it when I say I do not plan to push things to verify it being more durable than a C4.
That said, if the AOD does begin to slip, now knowing there is a small block C6, I will likely pop in a C6 and a Gear Vendor OD unit, just to be able to handle the power of even the mid-level street/strip build on the 351W. An alternative would be to get an FMX and drop it in with a GearVendor OD, as those FMX tranny units are definitely tough. But, they are very heavy (cast iron case) and I do not see a lot of vendors offering as wide a choice of high performance parts for the FMX, which is a shame as the FMX is really a well designed tranny.