I need to draw one…
Then you should definitely get some extra help, this thing has a weight of almost 30 tons!
Reactivated. For some reason I couldn’t post in the Archive room. 
While I see they did some R&D to make the M3 into a flame tank and AAA tank, you know they should have followed the Germans ideas and turned it into a 90mm tank killer.
That is an ‘assault’ tank with a forward firing 90 mm with fixed transverse. Not sure if it would have been able to fit it in the middle of the chassis, but still, taking out the 37 and .30 cal gun, should have saved enough weight to allow it, plus make it alot lower in height.
Deaf
The thing must have been an Admiralty design, I’m almost surprised the interior pic doesnt show a telegraph… 
As for installing a large bore gun in the super structure, I’m not sure the hull could stand the strain of it. Cant use a field gun, it may not have the strength required to fire the hotter loads of A.P. shot munitions, and the recoil system will need modification,as well as the suspension. Then there is the question of ammo storage, placement for efficient loading and case disposal. It may end up looking like this inside,
