Out of all automatics out there, which one can take the most beating under racing conditions only ? I am a stick person, but I am leaning  towards a C4 , don't want a c6 , size and wiegh . Is anything else out there  ,  for a high power , low wieght car ?

Po ol Davie

Sparta , Tn.

Dave, the C4 when done by TCI or Lentech or any of several other shops will handle 800 hp pretty easily. The c6's more.

Ted runs a C4 in his altered.

Frank/Rebop

Bristol, In ( by Elkhart) 

Frank is likely thinking of my '57 racecar which has a C4 but my roadster has a PG bolted up to the Y.  On the scale of power losses attributed to using an automatic transmission the PG would be considered having the least losses while the C6 would have the most.  The C4 comes in close to the PG on that same scale which makes it a suitable candidate for a racing trans especially if needing a lower gear ratio for launch while still trying to maintain a suitable rear gear ratio for a quarter mile sprint.  On my end the PG tranny is about a third of the cost of a built C4 or C6 but I originally started using PG's back before the technology was available to get the performance and durability from the Ford automatics.  That's all changed now and as such I've got cars with PG's, C4's, and C6's.

Lorena, Texas (South of Waco)

Thanks ted, those were the facts I needed to know, I have been tossing around which one, either the pg or c4 , I am leaning towards a c4, because of a lot of little things that will work better for me. Thanks again

Po ol Davie

Sparta , Tn.

Just saw this information at C. Kellys pages...

Power loss for various auto transmissions:
Please remember these are approximate values, and were provided by Car Craft Magazine.
Powerglide_____18 hp
TH-350________36 hp
TH-400________44 hp
Ford_C-6______55-60 hp
Ford_C-4______28 hp
Ford_FMX______25 hp
Chrysler_A904__25 hp
Chrysler_727___45 hp

 Seppo from Järvenpää, Finland
www.hollowheads.net (just click the hole in the head to proceed)

The FMX like Hurricane John uses is quite efficient. I wonder where the prior but somewhat similar Fordomatic would rate?

Paul

Paul:

They are essentially the same transmission, so I would think they would rate the same.

John - "The Hoosier Hurricane"

In a race car the other factors would be Transmission weight, and strength. The FMX is evidently very good in the strength department, but it's approx. 100 lbs. heavier than the C-4. the C-4 also offers cheaper, easier to find parts, and the potential of a higher (from the 4R70W's) low and second gears. That would make it a candidate for a heavy, low horsepower car. Which Ted's roadster ain't!!   

Frank/Rebop

Bristol, In ( by Elkhart)