I just went through this myself...
The model you want is the OS Max 18CV-RX(S) Blue 11J (11860). It is a complete drop-in to an RC10GT. Everything bolts up.
http://www.osengines.com/engines/osmg2105.html
Here is a quote from that webpage:
-
General Applications: Good for all ready-to-run 1/10 scale cars & trucks that require a pull-start power plant. Especially good for off-road trucks. Differs from OSMG2102 in crankshaft length and carb type.
Special Features:
Dual-needle, 11J rotary carb
Recoil starter
Short crankshaft
Specific Vehicles:
RC10GT FT
Nitro TC3 RTR
Nitro TC3 RTR Plus
Will need these accessories:
ASCC8803 CLUTCH NUT RC10 GT
ASCC4312 CLUTCH NUT HTC3
Perfect for Associated RC10 GT Plus
-
You may have to trim your body to fit the large head heatsink and the new massive air cleaner (old air cleaner will not fit, the neck of the carb is larger on this model).
http://www3.towerhobbies.com/cgi-bin/wti0001p?&I=LXGGP8
Now I just need to sell my Associated .18 I bought first... :-(