To stiffen the Viper front end I always add triangle stock to all the front end corners where it is missing including the top hatch. I sand off the covering on the front firewall and make up a 1/8 front plate of good 5-6 ply aircraft grade plywood slightly larger than the existing firewall. I use the backplate mount as a pattern to drill out the mounting holes - and then apply slow cure epoxy to the firewall and bolt on the new 1/8 front firewall plate between the old firewall and the motor mount and let cure. The exisitng firewall is too soft IMO and the new quality 1/8 plate gives the motor a much better seat. You also gain some firewall glue area as the new plate contacts the fuse 4 fuse sides at the front. I replace the top hatch with a solid piece of plywood - no window needed and glue on with epoxy. I next drill three holes through each fuse side into the the motor mount and epoxy tooth picks or small dowls. These mods take a couple hours work at most and add a ton of stiffness to the front end as well as making as stiff a mount as possible on the VIPER for the motor to produce all the HP it is capable of. One last thing is that the GP motor mount is a very soft alloy - I prefer using a good Nelson backplate mount.




dan