My 66 project is going well, I do have one question. Going from a 240 6 to a 390, do I need to use later model springs, buy new springs, or will the original springs handle the extra weight? I am doing the I-beam swap with a 76 FE truck, but I read that the 76 springs are longer.

 

You should be fine with the originals, considering the 66 trucks were available with the FE engine. I do not believe there was any difference in the F100 springs back then to compensate for motors. If it sags in the front a little, you can always drop the rear to match....

--Mike

 

Thanks, Mike, just wanted to get it right the first time, of course those suspension nuts do seem to be easier to remove the second time.....