Thanks for all the input...i am currently running a powermaster 9100 chevy mini starter?The battery is also in the trunk.Iam using 1awg welding cable
With the battery in the trunk and saying you are using 1awg welding cable, do you have a positive cable and a negative 1awg wire going between the battery and the engine ?. If you are running just a 1awg from the battery positive up to the starter and using short connections from the battery negative to the back of the car, do you have another connection between the front of the car and the engine block ?. The power has to make a loop and if there is a restriction in either the positive or negative path, the starter might not be getting what it needs.
Another thing to look at is with a rear mounted battery, where is the voltage sense wire on the alternator connected at ?. If the voltage sense wire is up front, then due to the voltage drops on the cabling back to the battery, you may have 14 volts up front but in back have less to where the battery might not be getting fully charged.
Another thing to look at is the connections on things like the 1awg cable. Sometimes crimped on connections are fine and last a long time but maybe solder the lugs onto the wire.
The powermaster 9100 installation manual also states that the starter is not designed for high compression motors. They also suggest using a 1awg when the main cable is 7' long. If it's closer to 10' then they suggest using a 1/0 cable.
Also, has it always been this way or has the issue slowly been become worse and worse ?.
Maybe the battery is weak ?.