In my last blog, I described the build/modifications to a 1991 Mustang 5.0 “roller” engine that I am adapting to drop in my 1966 Ford Ranchero. Since that time, I’ve completed the “back-end” of the engine to accept the Ford Toploader 4-speed transmission. As with the early build, the correct mixing and matching of parts is the secret to success. Here’s the low down.
The Ranchero came with a 1966 Ford Toploader 4-speed transmission and bell housing. In acquiring the 5.0 engine, I got a flywheel from a 1984 5.0 Mustang. Using the correct flywheel is critical. Ford’s small blocks are externally balanced. Ford made two versions. The early (1964 – 80) engines used a 28 oz. balancer (the small one) and a corresponding 28 oz. flywheel. After 1980, 5.0 engines used a 50 oz. balancer (large one) and a corresponding 50 oz. flywheel. You MUST match the weights. Very bad things happen if you don’t!
Next, Ford small blocks use a plate between the rear block face and the flywheel. This plate spaces the starter correctly and acts as a dust cover for the bell housing. Since the bell housing came from the 1966 Ranchero, I found a correct block plate on eBay for $40. After a resurfacing of the flywheel, I bolted it on using new ARP fastners. Next, I ordered a clutch kit from Summit Racing. Here was my first issue. Ford used two different bolt patterns for the pressure plate. Early flywheels have the 6 bolts in a “Y” pattern – two by two by two. Later flywheels have the 6 pressure plate bolts spaced evenly. Fortunately, the great folks at Summit have a super return/exchange policy and the correct kit was obtained. The final issue was the pressure plate bolts themselves. Ford (again) used three different threads on these bolts from 1965 to today. There is a 5/16 x 18 and 5/16 x 24 and an 8mm x 1.25. I tried all three before I determined I had the metic thread. Again a quick call to Summit and the ARP fasteners were in hand and the clutch kit bolted on.
A final check was made to determine if the starter that came with 1991 5.0 would be correct in the “mix & match” flywheel and backplate combo. It lined up perfectly! So, the job is done.
I’ve been cleaning and painting the transmission — all Ford Toploader 4-speeds have cast iron cases and they are HEAVY! One more note on the build – late 5.0 “roller” blocks do not have a boss to install the equalizer bar pivot bolt. MustangsUnlimited makes a great bracket that bolts to the bell housing/block interface to provide the pivot.
So, I’m ready to drop in the engine/trans combo and focus on wiring, and (hopefully) fire the beast up. Wish me luck and a Happy 4th!
