The Stovebolt Site Forums The Parking Lot Tons 'o Fun Big bolt front bumper on 3800

Has anyone looked at putting the big bolt front bumper on a 3800 frame by swapping the 4100 front frame extensions to the 3800 frame?

I haven't, but that might work. Are you sure the 4100 has "frame extensions" for bumper mounting and is not just a longer and differently shaped frame at the bumper?
The 4100 frame is nearly identical to the 3800 except for bumper mounting. The larger bumper also uses two bolt on heavy channel brackets to further support the bumper corners.
The splash pan between grill and bumper I believe is different as well. If different check how the big truck splash pan looks with little truck fenders?

I'm just going off of the frame info I could find at the heritage site. It showed extensions on the 4100 frame. I've worked with 3800 frames and a 6400 frame. I know the two ton trucks have the longer frame horns with those side brackets you mentioned, but I wasn't real sure about the 4100 frames. I have a line on a cheap complete 3800 frame that I'm thinking about using for my next build which will use a big bolt front clip and a 9 foot bed. I'd like to use the big bolt bumper as well, and hopefully use factory parts to mount it.