Gearing questions

[azoutlaw]

I have a 1980 F150 Ranger and I plan on building a 400 stoker for it. I have a stock C6 and a stock 9" with 31 splined , 300 ratio. My new engine will be used for everyday driving and occasional towing. I guess my question would be, are the existing gear ratios going to work for the extra HP and Torque. (approx. 375hp & 450tq). Any suggestions or comments would be appreciated.

 

[Fellro]

It depends what you want for a n end result. They will work if you want to keep the same rpms for highway cruise. If you want it to run down the quarter mile faster and don't care about highway cruise, then no, they will need changed.

 

[azoutlaw]

Thanks for your help. I was just worried that the drivetrain would need to be updated from the old setup.

 

[Fellro]

Durability-wise there really is no difference. The 3.00 will give you better highway fuel efficiency, but at the cost of not as snappy take off. If you would be doing mostly city type driving, the efficiency would be better with a 3.73 or such, as the mechanical advantage to get going is better.

You should have a factory issue 9 inch, which is a very commonly used rear end for drag racing. I think it should hold up for you.

 

[DNFXDLI]

You might want to play around with this rpm calculator to give you some numbers:

http://www.csgnetwork.com/multirpmcalc.html

 

[azoutlaw]

You might want to play around with this rpm calculator to give you some numbers:

http://www.csgnetwork.com/multirpmcalc.html

Thanks. The calculator is awesome. I think I will probably stay with the 3.00 for a while and see what it will do pulling a trailer uphill. I think the torque is going to be key and maybe keep those rpm's down as much as I can for some fuel economy. I appreciate the help guy's.