Background first. Old engine was 355 with comp 262h cam, performer rpm, holley 600, vortec heads. New engine has everything the same except now has a comp 284h cam. Just got it done and it runs good, nice sounding idle. Now I'm driving it around breaking it in and I have some questions. I now have a hughes 3000rpm lockup. Now I can only rev it with the brake on to about 2000 rpm. Is this about right? And I've been trying some half throttle, maybe 3/4 throttle launches and it flashes to maybe 2200! Will it only flash to around 3000 at wot? The trans also has a shift kit in it, and the old motor use to shift decently hard. But now you can't feel the shifts very much anymore. Does this have something to do with the new converter? I don't know but so far it seems like this engine just doesn't have the power it should have. Doesn't seem to accelerate much better than the previous engine. Btw, the previous engine only had 3000 miles on it-wiped out a cam lobe.

You'll never see full flash at part throttle. You'll never see the true stall speed without a transbrake. Driving around below the rated stall speed, the converter is always slipping. Converter slip will create heat in the tranny oil and will worsen fuel mileage.

Do a hard launch and let the transmission shift from first to second by itself. Providing you still have traction when it shifts to second gear, what do the rpms drop back to right after the shift?

The factory tach isn't know to be highly accurate.