I switched to a mopar 318 in my derby cars and now the motor runs but when i put it in gear there is no power?

I ran this motor once in a derby and lasted 5 minutes... car is good... just had mechanical problems.

The motor runs, has good compression, runs good, but when i put it in any gear the motor gets to much of a load on it..

i was able to drive it off of the trailer, but had to keep the peddle to floor. (the car has plenty of gas - fuel pumps works great)

I recently put a new needle and seat in the carburator.

my conclusion came down to two things ----

1. The timing is completely F****d up or (timing chain, distributor)

2. The torque converter is not working right

this motor runs on points, i checked them and they are good, i put a new set in.

I did notice that the points didn't open up right a couple of times but didn't make a diff. either way.

any suggestions??? on what it could be or what to look for?

this motor has a 904 trans on the back wish it'd have a 727..

the motor is actually a 78' which we switched back to points

i have it advanced about 8 degrees