Bright and early that next Saturday morning I headed back out to the garage to hopefully finish up what I’d originally thought was to be an easy engine swap (though, if only I’d had the foresight to read the engine installation instructions beforehand I would have saved myself a bunch of work and a lot of heartache). After replacing the flexplate and reinstalling the transmission I went ahead and installed the assembly into the Model A for the second time.
The Ford Racing M-6007-X302 is a long-block assembly; no intake, carb, or distributor (as well as the aforementioned pulleys, water pump, and flywheel/flexplate). Once the assembly had been reinstalled, my next step was to install an intake manifold and carb. The Ford installation instructions do give you a Ford Racing part number for intake gaskets, and though you’d think I’d have learned my lessons with my previous incorrect assumptions, I went ahead and used a set of Fel-Pro gaskets I’d purchased ahead of the engine swap. Everything seemed to be going along just fine. I installed the new intake and torqued it down in the correct sequence and to the correct specs, bolted up my new Summit Racing 600-cfm four-barrel carb, and dropped the nearly new distributor in place. Then I installed a fresh oil filter, fresh oil, and finished filling the C4 with fluid. I also hooked up the radiator hoses, belts, fuel line, and attached the throttle linkage.
I had just finished double-checking the timing and marking the distributor location so I could pull it and prime the engine before start up when I noticed that the aluminum heads each had a large, partially threaded hole bored front-to-back—what now? This time I had the presence of mind to dial up the Ford Racing parts tech line before going any further. I got through pretty quickly and asked the tech guy what the heck those holes were for. Well, come to find out, the holes are there to accommodate what they call “thermactor tubes”. These tubes are emissions related and normally bridge the holes from side-to-side (one on the front of the heads and one on the rear of the heads). These are not needed on non-emissions vehicles and can be plugged with a plug set sold by Ford Racing. Well, not wanting to stop the install and hold off to the following weekend for a second time, I measured the holes and found they were 5/8-inch diameter with an 11-thread pitch. I jumped in the car once again and hit my local hardware store and picked up four 5/8-11x1-inch bolts to use as plugs. I got back to the garage and cut the hex heads off the bolts and using my die grinder cut slits into the bolts so they could be installed flush to the heads using a screwdriver. Thinking I’d passed the last of my hurdles, I dabbed the newly fabricated plugs with a bit of antiseize compound and sealed all four holes—now I should be ready to fire that baby up.