1954 Dodge Coronet starting/running issue?

I have a 54 Coronet that, i just cant get to turn over fast enough to fire, and cant figure out why its not starting. I have spark, fuel, compression, everything i need, but it seems like the 6v system doesnt turn the car over fast enough. any input would be appreciated..

How old is the battery? The battery might have enough to turn the car but not enough to turn it fast enough.

One thing I did many years ago but I don't know if it will work or just blow something up. I might have just been lucky. I figured the 6V system would only draw the power it needed so I put jumper cables from my 12V car (12V engine NOT running and never started!!!) to my 6V car and then tried starting the 6V car to see if it would fire up. Of course back then, both my cars were pre-1970. Not sure if that would work with a new car today. My car started so I immediately turned it back off and went and got a new battery.

I tried that with my dodge truck, and it got it to spin somewhat fast enough, but still didn;t fire