Body swap questions

[J Lee]

Will an '88 k5 body tub mount on a '79 chassis? I'm pretty sure that it will I just wanted to check with others to make sure before I buy the '88. Thanks

[68Timber]

You would think so, by 78 the tub had been changed.

[J Lee]

Thanks John, I was pretty sure the bolt locations are the same just looking to see if someone knew for sure. Now I just have to make sure the bolt pattern is the same on the front bumper. I know for sure the ends of the frames are different.

[Jonboy]

The body tub should be the same; most of the difference is in and around the rear seat footwell. The '78 and later K5's used a fold and tumble type of rear seat with a dropped footwell, while the earlier trucks had a fixed seat and flat rear floor from the rear of the front seats to the rear sill.

As far as the frame differences, the front horns on an '81- up frame looks like they are cut off versions of the earlier frame, and there are center bumper brackets. The '79 front bumper would have bolted directly to the frame in the center lower hole. You could cut the earlier frame and use the later bumper. The rear frame horns will be the same, but use the brackets that correspond with your bumper (they are different).

[J Lee]

Johnboy is the bolt pattern different? I know the 81 up uses brackets in the center but they look to be the same angles. Like GM just decided to use a bracket for all 4 inner bolts instead of making the lower 2 into the frame.

[Jonboy]

It's been a little while, but I want to say that the frame is just cut at an angle. The lower bolt hole is part of the front rail on the earlier trucks, but the bumper is peaked in the center and is more slanted (less vertical?) than the earlier ones. I think that is the reasoning for just cutting off the end of the frame. If not, it could have been.