I have a 88 f150 5speed with a 300-6 and i know a stright 6 is not what u would call a power house but what im not sure of is would i loose lots of power if i put 33inch tire and a lift kit on it or how bad would it be for it overall cause i dont wanna have to be in third gear all the time lol. Or what do u think would be the biggest i could pull with out alot of power loss. Can anybody help please? THANKS!!!

 

The 300 builds it's torque down low, so turnin 33's shouldn't be an issue.

 

You didn't mention if you have a 4x2 or a 4x4 truck.

Tires taller than 31 x 10.50 -
The 4.9L engine will be a wuss when trying to pass another vehicle above 55 mph.
It will turn the tires and drive okay at low speeds though.

If 2-wheel drive, 31 x 10.50 on 8" rim is the largest tire without a lift.

If 4-wheel drive, 33 x 12.50 on 8" rim is the largest tire without a lift.

My 2¢