40 to 50 rwhp, they also claim 5 tenths off 1/4 mile times. Is this true? Any input would be great

 

You might cut .5 off your 1/4 time, but a converter isnt going to make any horsepower.

 

converters do not increase the engines power, it simply allows the engine to stall up at a higher RPM to launch etc. This lets the vehicle launch in the powerband of the engine.
now the 2nd part is true. Converters can knock off 1/2 off your ET.

 

exactly. Your picking up time due to the stall speed and lock up over a stock verter..
John

 

actually a converter robs you of power if you went to dyno it

 

True. I did see a small difference from stock to a 2600 stall. I would imagine a higher stall would be worse. A dyno number however, shouldn't be the only tool you measure gains with IMO.

 

true

the stall will be lighter rotating weight,and the fact that you can flash it higher and stall it in your cam range,so the motor will work right

 

only if you put the sticker in the window

Seriously though the guys above summed it up.

 

It seems like most converters also show efficiency, which might be where you see a difference at the dyno.

 

stall make your power stay at better power range. that does not mean more HP.