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70 Jimmy · 12-02-2002, 05:03 PM

On the first pic. I bolted the crossmember up to the frame and drew a line where they meet. After unbolting the xmember, I continued the lines down the front and rear of the xmember. Next, I drew perpendicular lines where the the crossmember goes vertical to the ground. This gave me a reference line that wasn't interupted by curves on the edges of the xmember. It is also a cut line, so keep it. I measured 1.5" down from that reference and drew a parrallel line. When the drawing is done, you should have a rectangle that "wraps" down the front and the back of the xmember where the frame rail will sit.

Next, I cut the upper "rectangle" out, checked my measurements (1.5") and cut the rest of the rectangle out. You should end up with one rectangle with the crossmember bends at the ends and two squares for each side. You can toss the squares.

Now match the rectagular peice to the notch. It won't be perfect, but it's definetly weldable. Weld it in.

Originally, I put plates on the outter sides of the notch but then I decided that i didn't like flat metal on metal. The insides are "boxed" Rust is always an issue around here. Besides, there is alot of strength in the other components after it's bolted up.

On the steering rod clearance, I just notched it 1.5" down and back from the edge. When in doubt, go alittle further.

Because of the notch, I had to cut the motor mounts and make a plate to bolt them onto the xmember. I will be strengthening these because I have a big block. I may actually make my own if I'm not happy with the modified SBC ones. I couldn't bring myself to cut up a pair of BBC brackets. As a 4x4, my truck ran a BBC in it for 5 years on SBC mounts (slightly modified) with no problem. I wouldn't do it unless you're confident in your fab skills.

The last two mods are not necessary for the other style of notch (from frame rail to rail). However, after thinking about it and talking with a few fabricators, I think, over all, this is stronger. Do what feels right.

I've meant to write up an entire article on this but I really haven't had time. Plus I haven't finished yet. Plus, someone's already written one.

Hope this helps

12-02-2002, 05:03 PM	#15
70 Jimmy aka Crusher, Crushergmc Join Date: Mar 2000 Location: Oregon Posts: 1,834	On the first pic. I bolted the crossmember up to the frame and drew a line where they meet. After unbolting the xmember, I continued the lines down the front and rear of the xmember. Next, I drew perpendicular lines where the the crossmember goes vertical to the ground. This gave me a reference line that wasn't interupted by curves on the edges of the xmember. It is also a cut line, so keep it. I measured 1.5" down from that reference and drew a parrallel line. When the drawing is done, you should have a rectangle that "wraps" down the front and the back of the xmember where the frame rail will sit. Next, I cut the upper "rectangle" out, checked my measurements (1.5") and cut the rest of the rectangle out. You should end up with one rectangle with the crossmember bends at the ends and two squares for each side. You can toss the squares. Now match the rectagular peice to the notch. It won't be perfect, but it's definetly weldable. Weld it in. Originally, I put plates on the outter sides of the notch but then I decided that i didn't like flat metal on metal. The insides are "boxed" Rust is always an issue around here. Besides, there is alot of strength in the other components after it's bolted up. On the steering rod clearance, I just notched it 1.5" down and back from the edge. When in doubt, go alittle further. Because of the notch, I had to cut the motor mounts and make a plate to bolt them onto the xmember. I will be strengthening these because I have a big block. I may actually make my own if I'm not happy with the modified SBC ones. I couldn't bring myself to cut up a pair of BBC brackets. As a 4x4, my truck ran a BBC in it for 5 years on SBC mounts (slightly modified) with no problem. I wouldn't do it unless you're confident in your fab skills. The last two mods are not necessary for the other style of notch (from frame rail to rail). However, after thinking about it and talking with a few fabricators, I think, over all, this is stronger. Do what feels right. I've meant to write up an entire article on this but I really haven't had time. Plus I haven't finished yet. Plus, someone's already written one. Hope this helps __________________ "KEEP IT DOWN!" 70 Jimmy 454 2wd 56 GMC Big Window "It's funny till someone gets hurt, then it's freakin' hilarious" Last edited by 70 Jimmy; 12-02-2002 at 06:15 PM.