So I'm gathering info on doin a sfbd. And I'm gonna cut the tops off the stock rails and slide my 2x3 into it an weld it back up then do a back half. So I need to know some things I can expect on this. Like body mountsand such. I know I'll have to raise the tranny tunnel. Will I have to trim things under the cab to get it down. And how much of a body drop is it on yotas I've heard 3.5"-4"
for starters why take the time to cut the already boxed frame to re box it? just cut the front frame clip off and with the new frame incorporate the Z and run the rails back. and im pretty sure if you wanna lay rocker not pinch maybe not all the floor but sum will need to be trimmed to fit then just make you body mounts with left over 2x3x .120
The reason for not just cuttin it all off is space and I know it'll be straight and eveything right under the cab. Also it'll be some extra metal IF I end up draggin it some I also saw someone else do tht and thought it was pretty good idea
It really isn't the best idea. Once you cut the top off the frame it looses its structure, and it wont really be square after that. I've done it once, and never again will I. Once I cut the frame everything wanted to pull, and I spent so much time with a portapower and ratchet straps to get it close that I really would have been better off taking measurements and building a frame. Plus it looks so much cleaner. Also if you cut the top off and lay tube in it, then drag through the bottom you will lose a lot of structure, unless you plug weld the frame near the bottom every few inches. And it really doesn't look that good. Take it from someone that has done both ways, its better and easier to just build a frame from the front clip back. As far as how much, just measure yourself. Take a level and put it under the frame, and measure from the top of it to where you want to body drop to (pinch, rocker, door, whatever). How limited are you on space? You have to take the cab off to do this, same with building a frame. I don't really see the difference, and don't really think this is a good way to do it. Would you have enough room to strip your truck down to a bare frame? If you do, what about bringing it here (3 hours about), and I will help you build the chassis, and then you can take it home and do the rest (4-link, bags, etc). The way I like to build body mounts is to stick the frame up on jack stands with a piece of 2x3 under the frame running perpendicular to the rails and cab. I set the cab on that, either on the pinch or with it folded if you want to lay rocker. And then I center the cab up side to side and front to back, and build the body mounts from under the truck. Then lift the cab to finish them. To me this is the easiest and most accurate way.
is doing 2x3x0.25 from the firewall back as well, i also had thought about just trimming down the original frame to 3" of height, but my friend talked me into just hacking it, doing my z down to the 2x3 and running fresh all the way back, as mentioned earlier, saves time, looks cleaner, etc. To TwistedMini's about the body mounts. You say you put a piece of scrap between the frame and cab to build the mounts, is this to keep an air gap to improve cab dampening (like factory setup)? We were going to just sit the cab down on the frame and make some rubber padding to try to attenuate vibration, etc. If this is not the reason please let me know why.
1/4" tube is really too thick, just so you know. And no, what I am saying is put a piece of 2x3 under the cab width wise, that is wider than the cab. This is so you can set the cab down over the frame, and the 2x3 will hold the bottom of the cab even with the bottom of the frame. Its not permanent, just something you set the cab on to level it out. I build my cab mounts when the truck is sitting like this.
It was just a thought I seen 2 guys do it one on streetsource an one on yotascene. But I guess I could build the frame first them slide it in after I hack the old off