Start by either mocking up the engine or measuring the frame to find the exact location of the crimp.
If you have a Spooky Tooth frame, measure 5-1/4″ away from the bottom bracket along the side of the down tube. Mark the area and wrap the frame several times with tape.
Your goal is to lightly squeeze the frame just enough to allow the motor mount bolts to clear. The amount to squeeze is very slight and care should be taken not to over squeeze or squeeze unevenly.
Evenly place the jaws of a set of vice-grips onto the taped area of the frame. Be very certain the jaws are even and begin to gently squeeze the frame. Keeping the jaws in place, tighten the tension bolt of the vice-grips and squeeze again. Repeat this process several times. Move the vice-grips to the opposite (top or bottom) side of the taped frame area and repeat the last steps of squeezing.
Longer M6 studs may need to be installed in order to fit the front steel mount. Your final project should look something like this: