I have an 89 gt and i recently put my battery in the trunk and put in an msd 6al at the same time. i wired the msd right to the battery with 8ga wire and the batt cable is summit racing 1ga. when the car is hot it doesnt want to start like if the battery was almost dead. is my shi**y stock alternator the issue or is it something else?

 

when relocating the battery to the trunk you need to make sure all grounds are secure and in place....when I did this I put a firewall to heads strap and a block to frame strap and scuffed paint at all ground locations and grounded the battery to the trunk spare tire well in the back and ran a charge wire to the always hot side of the selonoid and the heavy cablefrom battery toalways hot side of the selonoid......now I do have an optima battery and a powermaster single wire alternator as I have converted everthing in my 85 to electric like,water pump, fuel pump, msd ignition, extra pillar gauges and nos bottle heater...ect ect.... and mine has never had an issue since I did this upgrade but it does crank a little slower when hot soaks occur because my long tube headers wrap around the starter and the added heat causes extra resistance in the starter windings ....hence it'll crank a little slower...but if you don't have long tubes then possibly the windings and or magnets may be weak in the starter as a starter works off of magnetic repulsion so it could need a starter if all your grounds are in place and you have verified that you are charging the battery at the back viaperforming a alternatorload test

 

Did you fool with timing when you put in your ign. box? Too much timing will cause slow cranking.

 

I did not change the timing, i just regapped the plugs as per directions with the msd box. I have my battery grounded to the side of the trunk and i have a ground strap from the block to the inner fender up front. i have hooker shorties not longtubes. what is this charge wire you speak of? the car starts up fine when it is cold but if i drive somewhere and start it to go home it turns slow.

 

the charge wire is the big wire on the alternator harness...you'll have to trace it and see where it goes

 

i have the same starting problem as you. my dad knoced the timing back and it started fine and then its back to doing it again, i think my starters shot.