The Ford Barn

dmoz · 10-25-2024, 11:52 AM

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!

Ol' Ron · 10-25-2024, 12:06 PM

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.

tubman · 10-25-2024, 12:27 PM

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.

5851a · 10-26-2024, 09:13 AM

Only cruisomatic in 64. No C6 until 65.

KiWinUS · 10-26-2024, 09:23 AM

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.

pbsdaddy · 10-26-2024, 07:36 PM

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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.

10-25-2024, 11:52 AM	#1
dmoz Junior Member Join Date: Mar 2020 Location: Texas Posts: 14	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!

10-25-2024, 12:06 PM	#2
Ol' Ron Senior Member Join Date: May 2010 Location: Chester Vt Posts: 8,985	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.

10-25-2024, 12:27 PM	#3
tubman Senior Member Join Date: Dec 2013 Location: Minnesota, Florida Keys Posts: 11,633	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. Last edited by tubman; 10-25-2024 at 01:09 PM.

10-26-2024, 09:13 AM	#4
5851a Senior Member Join Date: Oct 2014 Location: NE Iowa Posts: 1,767	Re: Cruise-o-matic Only cruisomatic in 64. No C6 until 65.

10-26-2024, 09:23 AM	#5
KiWinUS Senior Member Join Date: May 2010 Location: Charlotte NC KiWi-L100 available here Posts: 3,262	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.

10-26-2024, 07:36 PM	#6
pbsdaddy Member Join Date: Dec 2023 Location: From Pittsburgh, now call Delaware home Posts: 72	Re: Cruise-o-matic Sponsored Links (Register now to hide all advertisements) 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.