Question regarding torque converter

i'd take a look at the tranny - 78 had lockup trany's... not all converters will slide into a lockup 904.

if it's not a lockup i'd go for the mopar performance 175k - thats what I got in my 360 a body and I love it for 190 bux it's real hard to beat!

ps- you can tell a lockup quickly by looking at the imput shaft on the tranny - if the splines are all the way out it's a no lockup - if there is a non splined section on it then splines it's lockup!