Frame work 1970 C30

[rushingg149]

Replacing the frame from the cab back with a 1986 C30 frame, springs and hangers and rear end.

First things first, I’m refurbishing a 1970 C30 with plans of carrying my motorcycle and trailer on the bed, while pulling a bumper pull travel trailer. It has a 1969 396ci, with a 4 speed manual tranny. I’m replacing the front end with an ’86 front end with disc brakes and power steering. I’m adding a 5 speed manual transmission and an ’86 differential and changing out the ring gear and pinion, in an effort to improve road speed and fuel economy.

The truck has a 12' bed with previous frame extension. They butchered the end of the frame right behind the rear hanger and extended it with 4" channel iron slid into the frame about a foot and bolted with a bolt on each side, to create a hitch. The hitch is hell for stout but I'm not comfortable with the attachment to the frame. The frame has previously been extended 2 foot between the cab and rear end. It is a good weld however it is a butt weld across the frame, with little bracing.

My first plan was to replace the ’70 rear end with a newer ‘86 one, due to the availability the ring gear and pinion. The original ’70 springs are 51” from hanger to hanger and the ’86 springs are 55” from hanger to hanger. Due to the butcher job on the frame at the rear hanger I would have to add to the frame to accommodate the rear hanger and the front hanger would need some adaptation also.

I know the frames are different in shape and size but with some measuring I think I could do the fabrication and it would work better with less frame work then originally required.

The first question of many, I sure is:

What is the length I need beyond the rear axle to prevent overloading the front axle or creating a fulcrum, possibly taking too much pressure off the front axle while pulling a travel trailer? The present length is 13 feet center of axle to center of axle with 4 feet of a 12 foot bed extending beyond the rear axle. This will be a pleasure truck (retirement) not a work truck, I do not anticipate carrying heavy loads on the bed beyond the motorcycle and it’s trailer, approx. 1,200lbs. – 1,500lbs

Any suggestions and or warnings are appreciated. I will include pictures soon, or you can see the truck on a previous post – 1970 C30 delivery