Quote Originally Posted by MonzaRacer View Post
sounds more like you have other issues as your battery should handle this load if big enough, as a set of fans, fuel bump and msd shouldnt be pulling more than 30 amps and it really sounds like your starter cabling or to indirect of a ground path is starving the starter, remember resistance goes up as things get hot.
I was wondering which battery are you using and what are the specs on it?

Lets put it this way a good heavy starter even on a high compression engine shouldnt pull more than 250 amps when old. My old Pontiac had a 10.5 to 1 engine with a ridiculously low duration cam and it was a bear to start and it started with a 525 amp ac delco and boosting from my little 40 month autoworks battery and that engine even pushing nearly 275 cranking psi would fire up and never draw over 200amps.
Few things to look for, get a good digital volt meter, set it on ac volts and look for excess ac current with car running, if it goes over 50 to 60 milliamps
(0.050-0.060) and its better if nearer to 0.040mA AC current you have diodes bleeding too much ac current into your battery and it damages and drains them.
another thing even most of the larger fuel pumps should pull over 10 amps and fans around 20 amps(I had a super heavy duty one I cant remember where I got it and it only pulled 12 amps on high).
If you look for a battery look at reserve capacity and the CCA and CA. the lower the reserve the cheaper the battery and if the battery is say 600cca but 950 CA its not a good battery. kind of like the "1000" watt amps that only actually make 100 watts RMS. its bs number to sell them.
Look for high reserve capacity and high CCA like 800-1000 and CA should be within 200-250 amps. Then go over your connections, I use 2/0 battery cable to starter I crimp and solder all my connections, and use many grounds like the woven stainless braided ones. I try to put 4 on an engine 2 front and 2 back and 2 to body for 6 total. Electricity does weird things and I have shut up many a cars radio whine when rewiring and adding grounds.

Good advice Monza, I'll take a look at my grounds, etc. For the record, I'm running a brandy new optima red top, but not sure of the CCA or CA right this second. Agreed though, electricity can do wierd stuff, so worth re-checking. I just figure with 13.5 -14 volts when running, I should be good to go. I know from my race car experience, that a decent compression motor with stout timing and MSD will sometimes be hard to start when hot. We used to wire the MSD to a switch, get the car cranking with no spark, and then flip the MSD on and it would fire up no problem. This is for 12:1 and higher motors and full race apps, but it worked like a charm.