Cruise-o-matic
 

I have a couple different Merc projects..i have decided to keep the flathead in the crew cab 😎. I came across this cruise-o-matic transmission out of a 64 thunderbird for next to nothing..anyone have experience marrying this transmission to a flathead (both good and bad)? Thanks in advance for the responses!

Re: Cruise-o-matic
 

I used a Merc o matic in my truck for many yeas, with a 3.3 rear. worked well for many years, sorry I sold it.

Re: Cruise-o-matic
 

Somewhere on the H.A.M.B. is a chart that lists the power required just for transmission "overhead". I believe the C6 "Cruise-o-Matic" (which I think you would have in a '64 TBird) sucks up about 40 hp. That doesn't leave much to run the car. I think a C4 is less than half of that. IIRC, the only other transmission listed as having a similar low parasitic draw is a Powerglide. I don't know enough to say if the flathead C4 kit (which is available) will work with a C6.

There may be some newer small car automatics that would be even better, but the complexity of their electronics, plus many other factors would seem to make them impractical.

Experiment away, please.

Re: Cruise-o-matic
 

Only cruisomatic in 64. No C6 until 65.

Re: Cruise-o-matic
 

I believe you have to use a crankshaft with rear hole to accept flex plate/air cooled torque converter. Not all flathead cranks will work.

Re: Cruise-o-matic
 

One of the differences between the curise-o-matic and the c-4 was the number of bolts on the bell housing. The cruise-o-matic had three. The c-4 had 5 in 64 and 6 in 65 and above. There are several types of flathead to c-4 adaptors available. Including, (I think), here in the for sale section. Just a personal opinion, but for about $200 you can find a worthwhile c-4. and simplify your project.