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Cranking amps to start a 350.

Here is what I found on w-body.com. Not sure how true this is.

8-Cylinder Engines.
The cubic-inch displacement (CID - not liters) equal the Cold Cranking Amp requirement. For example, a 350 cubic-inch displacement engine requires 350 CCA minimum. For colder climates, add 20% of the cubic-inch displacement to the CCA. Therefore, 350 x 0.2 = 70. So, 350 + 70 = 420. A 420 CCA or greater battery rating should be used.

6-Cylinder Engines.
Calculate the cubic-inch displacement per cylinder and multiply by 8. For example, a 231 cubic-inch displacement 6-cylinder engine = 38.5 cubic-inch displacement per cylinder. It is calucated as follows 231 / 6 = 38.5 cubic-inch displacement per cylinder. Then, 38.5 x 8 = 308 CCA minimum is required. For colder climates, add 20% of the adjusted cubic inch displacement to the CCA. Therefore, 308 x 0.2 = 62. So, 308 + 62 = 370. A 370 CCA battery or greater should be used.

4-Cylinder Engines.
Multiply the cubic-inch displacemet of the engine by 2. For example, a 151 cubic-inch displacement engine x 2 = 302 CCA. For colder climates, add 20% of the adjusted cubic-inch displacement to the CCA. Therefore, 302 x 0.2 = 60. So, 302 + 60 = 362. A 362 CCA rated battery or greater should be used.

Car batteries are rated by cold cranking amps (CCA rating), which indicates the battery’s power. The reserve capacity rating (RC) indicates how long you can run car accessories and still have enough power to start you engine.

Since starting a car in cold weather can take up to twice as much current to turn over a cold engine, cars in colder climates would benefit from a higher CCA rating. Check your owner’s manual for the original equipment manufacturer’s (OEM) minimum requirements needed for your car; select the battery adequate for you needs. Buying one with an excessive CCA rating may be a waste of money. In every situation, more RC is better.
 
What RPM & OinO said. Handy formulas as per oino....

Also, performance motors can build compression when hot, or when the timing is just a touch off.
On a 350, 600 cca's is my tool of choice on a block mounted starter. You want a reserve for like at the park, running your CD player, your lights, fuelpump, cooling fans, lights and ignition. Need your electrical system balanced.
A good strong battery, being charged by a good strong alternator, everything fused....
 
Chris, I have an Odessey 680 battery with a Chevy 350 with 10 to 1 compression and it cranks right over hot or cold. I also run a 100amp alt. with everything fused and relays where needed. It is really a small battery and can be mounted anywhere in any position. I have mine under the seat without having to cut the floor.
 
Would a blown SBC 350 need more than 600 cca's?
 
I wanted to use a battery from a mazda miata. 5-1/8wX7-3/4LX7-1/2H
but only 370 cca. I'm thing will be ok. I don't really have any accessories.
 
I am a big believer in lots of battery capacity. You leave the lights on for 30 minutes or so, and it aint gonna start back, or have a little tuning issue where it is hard to start and it may not start.
 
I am a big believer in lots of battery capacity. You leave the lights on for 30 minutes or so, and it aint gonna start back, or have a little tuning issue where it is hard to start and it may not start.
What he said!!! 2 amps per cubic inch till you get to 400, then 800CCA from there. A good starter like a Tilton will probably draw "only" 200A to crank a 350, and if she fires in a couple of cranks, no problem. BUT you pull 200A for say 10 seconds and your'e in a very different scenario where battery size rules. If the battery is under capacity it will suffer plate damage in very short order from the heat and gassing, and quietly die from self discharge one night in the garage. Automotive batteries are shallow cycle batteries designed to give big current short term, and not rated for any significant discharge cycles. That means discharge below 11.75 OCV shortens the life dramatically.
 
That is one of the advantages of the Odesey. It can be fully discharged and recharged many times. You are right though it doesn't have alot of reserve if it doesn't start. If I ever replace it I will go larger.
 
That is one of the advantages of the Odesey. It can be fully discharged and recharged many times. You are right though it doesn't have alot of reserve if it doesn't start. If I ever replace it I will go larger.
I am sure the Odessey is a fine battery. Being of the AGM type its a good automotive choice. AGM batteries are indeed able to with stand a gentle deep cycle discharge and charge over many cycles, however the huge current demand of a starting application repeatedly discharging the battery past 80% is quite another thing that not even the finest AGM battery can be expected to live with for long.
BTW conventional voltage regulated alternators don't help by hurling current into a discharged battery just when the battery could use a more gentle non heating and gassing approach. But thats another topic.....................
 
I am sure the Odessey is a fine battery. Being of the AGM type its a good automotive choice. AGM batteries are indeed able to with stand a gentle deep cycle discharge and charge over many cycles, however the huge current demand of a starting application repeatedly discharging the battery past 80% is quite another thing that not even the finest AGM battery can be expected to live with for long.
BTW conventional voltage regulated alternators don't help by hurling current into a discharged battery just when the battery could use a more gentle non heating and gassing approach. But thats another topic.....................

What He said!:thumbsup:
 

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