A much larger problem arose; actually two related problems.
1) The suspension and exhaust system is all molded as one piece, looking toylike
2) The rear suspension needs to be boosted to accomodate larger rear tires. This will necessitate the total rebuilding of the aft ends of the leaf springs.
First, separating the exhausts:
Then, adding to the chassis frame to accomodate the extended rear suspension....
Also found the new engine was too short for the driveshaft; so the driveshaft had to be lengthened by 3mm. Amazingly, the left exhaust also had to be shortened by the exact same length to fit the new engine.