compression ratio

[sgs]

Does anyone know the stock compression ratio for a 1970, 390, 2V ? So when you tell me what it is could you also tell me where you found it ?

Thanks
sgs

[FORDification]

8.6:1

http://www.fordification.com/data-1970.htm

[sgs]

Thank you Fordification! Once again, this site is incredible if you know where to look, and super friendly when you don't.

OK so one more question. Do car engines have a different compression? How do I tell if I have a car or truck engine and does it matter? Whats the best way to raise compression as I do my rebuild? How much compression can I pull heavy loads with on regular pump gas?

sgs

[averagef250]

For pump gas on a 390 I would stay below 8.5:1 with a grunt cam and a heavy load. If you run the pistons tight to the deck you can run a bit more and aluminum heads are good for a point.

In my experience compression is your enemy towing a load. The lower the compression the more efficient the engine seams to operate under a long hard pull.