torque steer

I have a 68 barracuda. I put in rubber motor mounts and tied unibody. It has 402 stroked 360. I step on gas and car goes right and i have to correct with steering wheel. Didn't do this when it had solid motor mounts and no ties. Please help very dangerous.

Did it have the 402 when you had solid mounts and no ties?

Are those two things the only change?