I have two Lifelike 98 C5 Vette's and 2 98 Vipers. The Vipers are noticable larger cars than the vettes.

if it has a can motor its a T chassis

I found that the Vettes are M chassis. I'm not sure what the Vipers are. They have a metal front axle that has 2 positions. Maybe they are Tyco cars.

Pics would tell a lot. Theres never been a LL viper, so Tyco or JL/AW are your most likely culprits.

Definitely not AW so probably Tyco.

As has been pointed out, if the Corvettes are Lifelike, they most probably use the M chassis. The M chassis will have a metal guide pin held in place by the front axle. The T chassis, the other possible Lifelike chassis, has a pressed in guide pin, dot traction magnets and there is no front axle. Both the T and M chassis fit all the Lifelike bodies.

The Viper cannot be Lifelike. It is either Tyco or Johnny Lightning. If the chassis uses an inline armature (like the Lifelike), it is Tyco. If the chassis has three gears running along the top, it is a JL.

Joe