Give me a few and I will check.

Ok the stock Traxxas chassis is slightly longer. This is because the stock chassis has little step ups in it so that it can sit on top of the bulkheads even past the flat mounting spots in the bulkheads. As far as the distance between the actual bolt holes in the chassis for the bukheads from the front and rear bulkheads the chassis's are the same. The only other difference I saw, is the trans in the stock chassis sits further back. Ive seen people have to trim the extra material off of the stock chassis when installing aftermarket bulkheads. I can upload pics to help you better understand my explanation if needed.

As long as I know that the distance between the bolt holes for the bulkheads is exactly the same for the stock chassis and the FLM 10800/10900, I am set.

Thank you again.

Yup, FLM confirmed on email that the chassis braces are all the same on the FLM10700, FLM10800 and FLM10900.

Thanks for your inputs all. :)