I have MP's trunk mount battery kit in my 70RR. I have a hot start problem motor slowly turns over. My question is I believe the positive cable is 2awg would a 0 or 0/1 pass more current to help this problem. Starter is good, battery load tested good, all connections are clean and tight.

Where is your ground/grounds?

how did you test your starter to know it's good? could the starter be getting heat soak from the headers? I've read lots of problems on here where a starter works great when cold, but cranks very slow when warm/hot; regardless of where the battery is located.

Battery grounded to frame, motor grounded to K member and to body. when motor was hot used co2 to cool starter.

(1) get it good and hot (2) disconnect the trunk batt cables (3) set a known good batt by the Dr front wheel on the ground (4) connect jumper cables, black to batt neg/starter case ear and clamp large/small starter terminals with one end of the red cable & last connection, other red end to batt positive post & see if it cranks normal. work fast for a valid test (while it is still very hot) and secure the red cable on the starter two terminals tight so the clamp dont move a bit when it cranks & contact the starter case. Yes I dont think 2AWG is enough & you've covered everything else ex tight eng & thats pretty rare

I would double check all of the grounds and make sure they are good and clean. Make sure the grounds are connected to bare metal and not a painted surface. I have always used 2 gauge battery cable with relocated batteries and never had a problem. My 67 Camaro has a 572 with 2 gauge cable and fires right up.

If that cured the problem, I'd say the starter is the problem. You say "the starter is good"...how do you know?

I run 1 gauge and my battery is in front.No way would I run less than 1 gauge in the trunk.My 12.5 440 with the mini captured in the headers fires like a /6 even hot.Rocky

Voltage drop is NOT your friend!


I run 2/0 cable for the main run and grounds for starter/engine.

I found some 2/0 jumper cables at a truck stop. Red and Black. Thats what I used to mount my batteries (2) in my trunk. Never had a problem. Here a site that has some good info on cable sizes and amperage that can be handled. http://www.directwireusa.com/What-Welding-Cable-Size-Chart/ also be aware if you're running headers heat soak is a big problem on our cars. If anybody knows a good mini starter that wont heat soak I'd sure like to know.

I had slow start when hot with 1 gauge + wire and chassis ground in the trunk and engine compartment.

I added a second ground with 2 gauge from the trunk to block and that helped quite a bit. Done again, I'd run even heavier + wire.

My mini is a reman from Advance.Its been in at least 15 years and the 2 inch TTIs capture it real good with the Lakewood.It always starts easy even when in the 90s here.I run the biggets battery CCA wise that fits and 1 gauge cables.12.5 domes in the 440 and it spins like a /6.Rocky

Rock has a good point, even tho his cables are small he might need more battery (or a combo of both issues). They ain't cheap but it'd be easier than changing out your cables. maybe he could borrow a bigger/higher CCA one from a friend just for a quick test.

You dont say how old the cables are.I had a set that was about 8 years old and had slow crank.Cables looked new on the outside but under the sheath they were corroded.Thats when I went 1 gauge.Just remember the bigger the wire the less resistance and less voltage drop.Rocky

2 gauge cable, 1000 cca battery, 5 year old cable. mini is year old. cut cable open no corrosion. Have taken battery to two diffrent stores for load test both say battery good. I asked what does good mean and of corse I get the usuall shrugg of shoulders and stupid look.

good battery high CCA battery fresh mini fresh cables. about all that is left is the cables ain't big enough

I ran 4/0 cables when I had a trunk mount battery. Overkill? Probably, but I had it and it was free.

welding cable is a good choice since by design the insulation is thick cuz the cables are getting moved constantly & flexible/multiple small strands of wire & it's reasonable & here at least when you buy some cable and terminals they'll crimp em on for free (not a dealbreaker but every little bit helps) & I would also solder em also. EDIT just mockup/measure the exact length you need ahead of time