The Stovebolt Site Forums The Shop Area Engine Shop Original or IFS?

I'm about to start a major rebuild of my 1950 1/2 ton truck. I plan on adding a little HP to the 235 engine so I can run on the highway at about 60-65mph. The few people I've talked to are telling me I have to change to IFS, either Mustang or Pacer. If I rebuild the original, is there any reason this won't handle those speeds without being white-knuckle ride?

Assumimg that the front end is in good condition there is no reason you cannot run at those speeds. You'll want to change the REAR end ratio to 3:55 gearing however.

Properly done your existing suspension will easily handle that kind of speed and should manage much more. Its the axle ratio and splash oiling that will limit your speed, and brakes that will limit safety, long before that straight axle design is a problem.

take a look under any big rig on the road, all use straight axle, just dont ride and corner as smooth as ifs. But if you do decide to go the ifs route do yourself a big favor and just buy a mustang II kit that fits over your existing frame rails, by the time you are done fabbing and fitting and rebuilding a wrecking yard peice the price will be about the same.

The plan (until my wife intervenes) is to rebuild everything, including the front end with all new bearings, etc, reduce the rear gears to 3.55:1 or 3.08:1 and rebuild the full pressure 235 with some modifications.

I don't have the budget for a new MII kit, but didn't want to do all this work just to be limited to 50mph from the front end.

My other concern is the front springs. The PO removed some leaves to lower the front end. I jacked from the frame rails and had my 3-ton jack all the way up to its limits and the wheels still weren't off the ground. Those are some soft springs.

Thanks for the input.

Look at the main leaf on your front springs closely and make sure they are not broken. I had a broken one on my '52 and did not know it until I put it on a lift and noticed the axle hanging way down on one side.

Don't be afraid of the straight axle front end!!! But, make sure that the kingpins, shocks, tires are balanced, and the usual front end stuff is OK.

You should probably change the front wheel bearings to rollers which take side loads better, but this is more a safety issue rather than a performance issue, but should be done.

I did all the previously mentioned stuff to my '52 1/2 ton original front, and I can cruise all day @ 70 without shake, shimmy, and/or white knuckles - and the highway ride is a smoooth at my 300M. Off the smooth pavement it rides like a '52 1/2 ton with an original front end as expected.

Your biggest obstacle to cruising @ 50 is the low gearing of the rearend to keep the engine from winding up too tight as was previously pointed out in an earlier post.

The '52 has the driveline from a '77 Blazer with higher rearend gearing which allows it to run at highway speeds.

I will continue to spend my money now on other restoration items, but an IFS is way on the back burner because the original is working just fine.

'52 Ted