I think you have too much gear for the amount of torque you should put out. The one i'm building is going into a 2,000 lb with driver Daytona tube chassis car. We're going to run either a 4.56 or 4.86 gear with a PG. We fully expect to run 5.50's. May have to go up on the converter it's a 5500 stall.
JMO
Zip.