Not sure cb and with only one on the car I can’t get an exact measurement.
But using the ends of the front bumper as a guide And how much it sticks out beyond the one mounted fender I would say that 68” is close.
Torchie
Here are my thoughts, FWIW.
Have you looked into an early Dakota, either for a front suspension clip or for a frame swap? Seems like you mentioned one some time back. I think the early Dakotas were about 68" wide. You get rack and pinion steering and disc brakes. Also the suspension geometry is much better with the Dakota than with the S10.
I have custom build 3 frames, but only because the stock frame was bent or too thin. It appears to me that the 49 frame is well build, although it would be improved with cross-bracing. I have swapped for a 51 Wayfarer, but it is still 200 miles away so I cannot measure.
There are some Jaguar options you may want to consider for grafting on your frame, as it may be less work than fabricating body mounts for an S10 or Dakota frame swap.
The early Jag XJ6 (up until 86 or so???) is the narrowest and width would not be a problem. You don't see many of them in the US, but the Aussies still like them for IFS swaps (see ozrodders.com)
The later XJ6 is 67.5" outer tire bulge to tire bulge with stock wheels. This may be too wide, and it is a more difficult swap that the earlier XJ6 IFS. I have one modified for my 56 Dodge truck, but it is wider, I think, that your 49.
I also have a later (98 or so) XJ8 suspension. Have not measured, but can if you would like. All of the Jag pieces are well built.
Team 321 makes a narrowed cross member to use pieces from a 2003-10 Crown Vic, but I think the narrowed one would still be too wide.
The Supra suspension is a nice package, but it is about 70" tire bulge to tire bulge with high offset wheels. I made a custom cross member to narrow the Supra suspension 4.75" for a 36 Dodge, but that is a heck of a lot of work.
The Supra is my favorite. Rack. Big brakes. Good geometry. Completed JDM Supra IFS CAN be obtained for $500 or so. Some Lexus racks bolt in to convert from RHS to LHS drive. If you are lucky, you can find an early Lexus SC in a salvage yard.
Hope these comments help.
Bob