47-55.1 Ifs

[PDW HOTRODS]

Does anyone know of an IFS crossmember or kit for a 1951 3800? I am thinking of getting one. I know the frame is different for the 1 ton, but the body is the same as 1/2 ton. I would shorten the frame and make it a short bed. The back of the frame is no big deal, but I might have to use a universal crossmember for the front and make it work. Thanks.

[fauXGT]

This is what I've got on my truck.
https://flatout-engineering.com/chev...es-1955-front/
The C4 Vette package was welded onto the stock frame.
I also have the C4 rear mount kit.
I can't say how it handles being I'm still working on the rest of the truck.
And due to a recent injury, I'm out of commission for a couple three months.

[mr48chev]

I'm thinking that the main difference between a 3100 frame 3600 frame and 3800 frame from the front cab mounts forward is the thickness of the frame rails.

The rail might be a little taller from top to bottom right at the point above tge axle center line but some dilligent calculating and slight mods. can get around that.

This is on my my photo bucket page but even with the assembly manual in front of you the numbers are hard to read.
This is 3100 and one of us would have to take some measurements on our 1/2 ton frame right at the spot where the axle runs under it and the independent would mount to show the measurments that you could compare with your frame.



Center of the front wheel to front of the front bumper is 33-7/8 on 3100 and 3800

https://www.gm.com/content/dam/compa...olet-Truck.pdf

This screen shot shows the frame rail thickness difference. Also the main part of the rail is 7 inches rather than 5-3/4, More beef, all on the bottom side.

[PDW HOTRODS]

I don't have the truck yet, seller not available for a few more days and I haven't seen it yet. It's an hour away. I'm trying to figure things out first. The kits I have seen say they are for 3100 to 3600 trucks. I haven't found info why they wouldn't work on a 3800. I thought the frame may be taller. I know a lot of people use S10 frame but I now they have there own problems. I have had quite a few 3100's but never a 3800.

[mr48chev]

Well there is no law that says that you can't use a 3100 or 3600 frame if you decide that there are too many issues with getting the 3800 frame the way you want it. Outside of the spot where the crossmember would mount and what you do for a kickup on the rear end as the 3800 frame is pretty straight and flat in back it shouldn't be too bad, stronger frame than the smaller trucks to boot. First thing is to get the 3800 home, get under it and examine it for anything that might be an issue otherwise.

[dsraven]

yup, like mr48 says, get it home and see what you have. I had a truck that was in pretty good shape from a walk around but when I got it home the farmer had installed the box back on the truck after having had a hydraulic deck on it for years. the hydraulic deck had been installed by somebody who had butchered things to get it to fit and then it was quickly removed with a torch. I only used the body parts from that truck as the frame was too far gone. with the assembly manual in hand, and an original frame for reference, you could fabricate your own frame from rectangular tubing if need be. or an original 1/2 ton frame could be sourced. most IFS will want a section of the frame to be boxed in so if the frame that comes under the truck is viable it could be modified to fit the IFS you go with. will you lower the truck or are you looking for a stock ride height?

[PDW HOTRODS]

I want it to be lowered and a good driver, not scraping the ground. I saw pictures and the frame looks in good condition but with body on it I couldn't tell on the front. The cutting and welding is not a problem, just wondering what's different that the crossmembers won't work, at least as is.

[dsraven]

I put a MII cross member under a task force 3/4 ton, it didn't fit the contours of the frame well and I assumed the problem was that the 3/4 ton was a taller frame in that area yo supoort the added GVW. I trimmed the cross member to fit. it is best to have a good idea of how things work before you do that though because the dimensin from upper to lower control arm pivot shafts need sto stay the same. if you know that then you're good to trim and check dimensions as you go.
welders series does sell a universal cross member that you build yourself, if that interests you. possibly they hve the correct dimensions as well. I suggest to do a little research on IFS geometry and how one angle affects the other etc.heidts used to have a written tech article on it in their tech section of the cataogue and maybe they could send you a link if you can't find it.

[dsraven]

sorry about the spelling mistakes. like always. haha