The first
Grumman fighter for the USAAC was a modified version of the XF5F-1 with
a more conventional nose and tricycle landing gear.
The XP-50/XF5F
led to the F7F Tigercat.
This
is a Jewel Like vacuform kit and I think it came out rather well for such
a basic kit.
There
is a Merlin kit of this, but check out the P-40Q pictures before you run
out and get one. You could also mod an MPM XF5F kit since most everything
is the same except the nose.