JB WELD Is awsome. My buddy had a crack in the water jacket on his Toyota FJ40 motor. He sealed it with JB weld. It was a huge joke about the motor being glued together in our 4x4 club. It would last about a year before theh eat and pressure would get to it. It bought him three years on that motor.
I Glued a 700R4 transmssion back together with it. My buddy had swapped a 700R4 into his 1970 Chevy Blazer. He was running down a trail a little fast and hit a water bar and aired the truck. Got the front end about 4 ft in the air. It nosed over hard when it landed. Suspensing did it's thing and the axle goes back as it comrpesses the suspension. Those olf Chevys did not run the clam shell motor mounts. It's basicly just a rbber block. So the motor and tranny went foward. Ran out of drive shaft splines and something had to give. Driverside Rams horn exhaust pipe sheared off at the collector from hitting the motor mount (normally 2 inches of clearence). Transfer case ripped off the back of the transmssions a part of the transmission went with it.
I JB Welded the broken section back on. Drilled the mount holes extra deep into the back of the transmission to get past the broken part. Heli coiled it and bolted it back together.
Still holding after 2 years!
One other thing to check if your going to pull that carb again is the EGR port. Once you get the carb off the plennum devider up under the car has the EGR port. Check and see if it's all carboned up. I had my 79 K5 plug up that port and only delivered EGR to one half of the motor. It will give you some odd looking plugs when that happens.