I have a 67 Chevelle w/ a 396/TH400 and the transmission has never felt
like it drives "right". The previous owner said it had a high stall
converter (2800?) and that it "slipped" a little till over 3K rpms.

When I drive it around town (never much more than 40-50 mph) it seems
ok. The throttle response is there ... the engine is tuned fine. But
after the throttle revs up, and the car starts to accelerate, it just
feels like the tranny is "slipping". I stomp on the gas and the tires
don't chirp ... the rear end ratio is 2.73, non-posi 12 bolt.

I can see the RPM drop on my tach as it goes through the 1-2 and 2-3
shifts. The fluid level is good, no major leaks and no "burnt" smelling
fluid.

Without being smart on transmission physics, it just feels like when in
3rd gear the tranny never "feels" like it is in a 1-1 ratio w/ the
engine. Like the two are never "locked" like on a manual transmission
or other autos I've driven. I can't explain it any other way.

My questions are: Is there any way to isolate the converter from the
tranny to determine if it is faulty? Are there any road test procedures
that could identify a faulty transmission?

I can get to work and back and around town no problem. I just don't
like the feeling of something in/on the tranny feeling off.

Thanks in advance!

If your tranny were really slipping, it would quickly manifest itself with burnt fluid and debris in the pan. Sounds like your converter is much higher stall speed than advertised. 2.73 ratio would be a real dog with a high stall speed verter. I would pull the transmission back, install a mild converter, change the fluid and filter and let 'er rip. Recommended next project, get some steeper rear gears if you wanna hear some chirp!

That 2800 stall will not quit slipping until your hitting about 80 mph or so with that 2.73 gear ratio.

You guys just made my day. I needed some encouragement before I committed to pulling my tranny just to swap a converter I wasn't sure was bad.

Any suggestions on the stall spped? I seen them as low as 1300 and (most) mild ones in the 1800-2200 range. I am looking for the best driveability around town. Chirping the tires is nice, but secondary to driveability.

If you intend to keep the 2.73 rear gears, then 2000 stall is plenty.

Went through something similar with mine years ago.

2800 stall +3.08 gear+ heavy car-Dog. :noway: