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Robin Lawrence · 07-11-2025, 08:36 AM

You didn't clarify your estimated amp draw on your car. I had a conversation with Larry Hill about this very subject late last year.

If you're running a carburetor with a stock type coil you can get away with a lot less.

I run an EFI system that uses wide band 02 sensors in each primary for data and 2 more in the collectors for the EFI system. Add a EFI High Pressure fuel pump, Large Cooling Fan, electric water pump, 2 Digital Dashes and a Race Pak the little items add way up.

Last car we logged years ago didn't have the Race Pak, 02's on primaries or digital dashes. I was drawing 60 to 65 amps during a chassis dyno run.

Since I was at Holley when I built this car I opted for the MSD 5361 160 amp alternator.

Fuel injection loves Voltage. I also have 2 Optima Red Tops that have worked well. Most times after a run the batteries state of charge is at 95% unless I run the fan and water pump in the pits to cool down.

I think that you cannot go wrong by having too much capacity.

Good luck!

Robin

07-11-2025, 08:36 AM	#5
Robin Lawrence Sponsor Join Date: Jan 2002 Location: Galesburg IL. Posts: 175 Likes: 248 Liked 705 Times in 119 Posts	Re: Alternator choice? You didn't clarify your estimated amp draw on your car. I had a conversation with Larry Hill about this very subject late last year. If you're running a carburetor with a stock type coil you can get away with a lot less. I run an EFI system that uses wide band 02 sensors in each primary for data and 2 more in the collectors for the EFI system. Add a EFI High Pressure fuel pump, Large Cooling Fan, electric water pump, 2 Digital Dashes and a Race Pak the little items add way up. Last car we logged years ago didn't have the Race Pak, 02's on primaries or digital dashes. I was drawing 60 to 65 amps during a chassis dyno run. Since I was at Holley when I built this car I opted for the MSD 5361 160 amp alternator. Fuel injection loves Voltage. I also have 2 Optima Red Tops that have worked well. Most times after a run the batteries state of charge is at 95% unless I run the fan and water pump in the pits to cool down. I think that you cannot go wrong by having too much capacity. Good luck! Robin __________________ STK 308 SS 3088