cross sills with a c notched rearend

[samples45]

Can someone post some pictures on how you did your cross sills for the bed with a c notch? when i got my truck the bed was off so im not sure how they fit anyway. thanks!

[tmoble]

is your C-notch higher than the top of the original frame?

If not, no work is required for the sills.

If yes, you'll have to decide if if you want to raise the whole bed a little or raise the floor of the bed, leaving the steel part of the bed at stock height.

On my truck, I had c-notches made from well casing or some large diameter tubing, left about 1.5" of frame above the notches. The top of the 3rd member hit the bottom of the bedwood and broke it out eventually without hitting the the c-notches. It was pretty low. Had I known I would have blocked the bed up 1/2' or so and put some kind of rubber bumpers to stop the axle up-travel.

[samples45]

Originally Posted by tmoble

is your C-notch higher than the top of the original frame?

If not, no work is required for the sills.

If yes, you'll have to decide if if you want to raise the whole bed a little or raise the floor of the bed, leaving the steel part of the bed at stock height.

On my truck, I had c-notches made from well casing or some large diameter tubing, left about 1.5" of frame above the notches. The top of the 3rd member hit the bottom of the bedwood and broke it out eventually without hitting the the c-notches. It was pretty low. Had I known I would have blocked the bed up 1/2' or so and put some kind of rubber bumpers to stop the axle up-travel.

I'm gonna keep the bed itself the same just raise the floor, go take a look at my build thread and you'll see what I'm talking about. I have two cross sills but don't know where they go. I'm not sure how I'm gonna get the cross sills to the bed sides and frame but also hold the wood since I'm wanting to raise it

[tmoble]

it's kinda weird how the bed works. The cross sills don't connect to meet the besides at all. The angle strips at the bottom of the sides are bolted or welded to the sides and to the outside boards of the bed. The large bed bolts with the offset washers go through the wood, the sills and the frame. The bolts that hold the metal bedstrips to the wood also act to hold the the whole wood platform together. Seems like GM went to a lot of trouble to avoid devising some way to bolt the sills to the bedsides. Maybe they thought it would concentrate too much load in small spots leading to cracking of the metal. I don't know.

The outside boards sit directly on the ends of the sills, several of mine had pretty nasty cracks.

[samples45]

Originally Posted by tmoble

it's kinda weird how the bed works. The cross sills don't connect to meet the besides at all. The angle strips at the bottom of the sides are bolted or welded to the sides and to the outside boards of the bed. The large bed bolts with the offset washers go through the wood, the sills and the frame. The bolts that hold the metal bedstrips to the wood also act to hold the the whole wood platform together. Seems like GM went to a lot of trouble to avoid devising some way to bolt the sills to the bedsides. Maybe they thought it would concentrate too much load in small spots leading to cracking of the metal. I don't know.

The outside boards sit directly on the ends of the sills, several of mine had pretty nasty cracks.

Hmm I thought the bedsides sit on top of the sills?

[57chevyman]

Originally Posted by samples45

Hmm I thought the bedsides sit on top of the sills?

the outermost board sits on the sills and angle strips sit on top of the wood. you have to drill the holes thru the wood to attach the angle strips to the wood. some of the bolts do go thru the angle, wood, and sill. the angles are bolted or spot welded to the bedsides

[Speedbumpauto]

Pic of my C notch, not above stock frame and relationship of sills. Also a pic showing the addition of 1x2 tubing to front of bed and 2" of the top of a donor rear cross sill and the welding/position of angle strips to raise the floor 2". What I didn't get was the welding of 2x2 pieces of tubing to the frame in the spots where the sills sit to raise them the 2" for the bed wood. I also got rid of those ugly bolt/washer things by welding studs into the sills and bolting them to the welded in pieces of 2x2.

[samples45]

Originally Posted by Speedbumpauto

Pic of my C notch, not above stock frame and relationship of sills. Also a pic showing the addition of 1x2 tubing to front of bed and 2" of the top of a donor rear cross sill and the welding/position of angle strips to raise the floor 2". What I didn't get was the welding of 2x2 pieces of tubing to the frame in the spots where the sills sit to raise them the 2" for the bed wood. I also got rid of those ugly bolt/washer things by welding studs into the sills and bolting them to the welded in pieces of 2x2.

thats good work! Im gonna have to raise my floor more then that! i have a corvette rear end and had to put a bigger c notch in it!

[samples45]

Originally Posted by Speedbumpauto

Pic of my C notch, not above stock frame and relationship of sills. Also a pic showing the addition of 1x2 tubing to front of bed and 2" of the top of a donor rear cross sill and the welding/position of angle strips to raise the floor 2". What I didn't get was the welding of 2x2 pieces of tubing to the frame in the spots where the sills sit to raise them the 2" for the bed wood. I also got rid of those ugly bolt/washer things by welding studs into the sills and bolting them to the welded in pieces of 2x2.

I like how you did that! thanks man!

[samples45]

Thanks everyone for the pictures!!

[BIGglaSS]

I'm also doing the C4 rear end, and I notched the rails 2". I was looking at this frame, and may do something similar for the cross sills over the step notch.
http://67-72chevytrucks.com/vboard/s...=673809&page=5

[Speedbumpauto]

I did find a pic of the 2x2 pieces of tubing I welded to the frame. Point is, if you add the same amount above the rear bed sill and the bed front as you weld to the frame for the cross sills to sit on, you can use the stock sills. IMO, you don't need a complete crossmember for the sills to sit on. They are strong enough by themselves and it saves a fair amount of fabrication. You could use 2x3 or 2x4 tubing to increase the ht. My biggest saving was ordering Mar K bed sides with angle strips not attached so I could weld them in where they needed to be.

[ChuckDriver]

Here's some examples of raising the whole floor.

[ChuckDriver]

One more.

[NASTY-LSX]

Originally Posted by ChuckDriver

One more.

May I ask what size wheels are those?? they look like 18's

[BIGglaSS]

Originally Posted by ChuckDriver

Here's some examples of raising the whole floor.

Do you remember where you found this one? I'd like to see more of the frame and suspension.

However, all those cross braces make it heavy! The factory only used four.

[ChuckDriver]

Originally Posted by BIGglaSS

Do you remember where you found this one? I'd like to see more of the frame and suspension.

However, all those cross braces make it heavy! The factory only used four.

It was on eBay a couple months back. Built by Hales Speed shop somewhere in Texas I beleive, some pics on Instagram @halesspeedshop

[Ricos54]

This what I did. Because my bed floor is raised I looked at the wooden square block that was used and added 3/4" which is the wood then cut some square tubing and made it the same size. Put the front sill on top of that and it made my bed floor the right height. The rack you see is my raised bed floor. Mine is different because I turned mine into a tilt bed floor.

[samples45]

Originally Posted by Ricos54

This what I did. Because my bed floor is raised I looked at the wooden square block that was used and added 3/4" which is the wood then cut some square tubing and made it the same size. Put the front sill on top of that and it made my bed floor the right height. The rack you see is my raised bed floor. Mine is different because I turned mine into a tilt bed floor.

I was really wanting to do that in my bed but try not to use so much heavy metal.. i was wanting to make it light and use those gas shocks kinda like on a hood but stronger of course.. I kinda talked my self out of lifting the floor but im still not 100 percent sure

[_Ogre]

it would help if you posted a pic of your frame with c-notch
i have a c-notch without the raised bed and then you have some extreme notches above
my truk rides at 5'' and has 2'' to the frame, this means i'd need to go 3'' more with my c-notch to set the sheet metal on the ground
the pic chuckdriver posted would lay frame, our frame is 8'' above our sheet metal

[samples45]

Originally Posted by _ogre

it would help if you posted a pic of your frame with c-notch
i have a c-notch without the raised bed and then you have some extreme notches above
my truk rides at 5'' and has 2'' to the frame, this means i'd need to go 3'' more with my c-notch to set the sheet metal on the ground
the pic chuckdriver posted would lay frame, our frame is 8'' above our sheet metal

[samples45]

heres another

[ChuckDriver]

Nice!

[Hilljack51]

I found a similar thread from the forum, and even though he's raising a steel floor it should be able to give you a pretty good idea as where to start.

http://www.67-72chevytrucks.com/vboa...d.php?t=443970

I really think that keeping the flat floor in the AD trucks by raising the floor to clear the tires and chassis takes projects to the next level.