The TR4 had, as OEM part, a 'torque reaction arm". I use this part. I left it
off once and I damaged my velocity stacks, on the inner fender wells, with
the additional engine rotation.
It uses a rubber bumper rather than hard mounting to the frame or body work.
There are several of these Torque Reaction Arms on my shelf, if someone would
like to try one. They might fit a TR3A with some minor modifications.
It is a simple bolt-on at the lower right hand side of the engine and snubs
against the frame. It is a bit of puzzle on why it works, but it does.
> I use rectangular mounts and I filled the chambers in the rubber blocks with
> window glue to make them more stiff.
> Additionaly I added a strut from the head to the fender to have less load on
> the motor mounts.
> Before I have done that, at a standing start always the left motor mount
> ripped off.