82 rx7 starter runs slow
 

Ok so I'm rebuiding a 82 rx7 gsl with se suspension and a new built by me 13b out of a se with 48 ida. I planned on posting the build thread when it's done.

Here is my problem. I have a new never started 13b. New battery, new battery cables , new starter, motor and trans painted with high temp enamel but not were the starter bolts and grounds to the trans. all my electrical systems work fine in the car. But when I try to start the motor the starter runs slow and battery cables get vary hot fast all my grounds are clean and new. So I added a ground from the battery to the block same problem. What am I missing I have never had so much trouble with a starter.

I also have 2 other starters that have tested good and when installed I get the same problem. I keep thinking it has to be a bad ground but I have all new cables and a new fresh metal ground on the strut tower. Anybody have any ideas?