luthj
Engineer In Residence
I don't think 3.0s are necessary with a 1:1 ratio/solid axle, the 2.5s should get all the force you need. The only benefit of the 3.0s would be better cooling in that case.
As far as travel, I would consider limiting the front to ~10". Especially with a softer rate. Too much travel can actually cause handling issues on road, and even rollover danger.
Which is probably why the 250/350 have such stiff springs. They are trying to improve road safety, as these trucks have a significant rollover risk, especially with service bodies or the overloaded campers folks use.
Spring wise, are the ford springs an odd shape? Its been a while, but custom coils are not prohibitively expensive, and you could get exactly the length and rate you need. Thats one of the main benefits of converting the rear to coils, you can tune the spring rate without the expense of new leaf packs, and height can be set with spacers or adjustable buckets.
As far as travel, I would consider limiting the front to ~10". Especially with a softer rate. Too much travel can actually cause handling issues on road, and even rollover danger.
Which is probably why the 250/350 have such stiff springs. They are trying to improve road safety, as these trucks have a significant rollover risk, especially with service bodies or the overloaded campers folks use.
Spring wise, are the ford springs an odd shape? Its been a while, but custom coils are not prohibitively expensive, and you could get exactly the length and rate you need. Thats one of the main benefits of converting the rear to coils, you can tune the spring rate without the expense of new leaf packs, and height can be set with spacers or adjustable buckets.