remove the grill and shell, mock the engine in there with just a engine stand, measure from the firewall to about 5" in front of the engine, then remove engine, replace grill and shell, then measure from where it would be in relation to the other measurement you took, take that number, that's how much you should cut out of the body to shorten it, everything will remain in stock location, and the engine will fit, without gaps. What you will end up doing is removing from the body inner ( sectioning ) to make it shorter, and in turn, that gives more engine clearence so, you havn't a need to make the car longer.