My T-5 Died Today....

[Unit 5302]

Originally Posted by showtire

I may be on another planet based on the text I have been reading, but here goes for what its worth: I have a 66 Ford Galaxie 500 XL Convert. She is stock with the 390, but has the Edlebrock4-bar & manifold. The original tranny was a slush box C-3. I had it replaced with a C-6 from a pick-up truck and yes it was hard to find. My mechanic is a racer and mustang lover and found the C-6 for me and actually wanted to keep it himself after he found it. POINT: He said I could rev my 66 to blow point, drop her in low and would twist the drive shaft off or blow the eng before, I hurt that C-6. That was about 10 years ago and she still purs. Thing is, she is an auto and I have never raced her, but my mechanic said it would be the same on the track for a manual?

Your mechanic is very unlikely to be correct. I don't have all the specifications on your particular C-6 (gear ratios, etc), but a properly driven manual transmission is almost always quicker than an automatic for mildly to moderately modified cars. The manual usually has 1-2 extra gears allowing for closer ratios to keep engine in it's peak powerband, a lower first gear to get a better hole shot, and they use significantly less horsepower than automatics as a general rule.

Obviously, the automatic has the advantage when it comes to consistency and ease of launch. It also has torque mutiplication, and torque converter options that allow for a higher stall speed which allows the engine to rev into it's lower powerband with the torque multiplication being applied.

Highly modified cars on the track are often seen with automatics for consistency (especially in bracket racing), and improved durability.

The C-6 transmission is very strong, but very large and inefficient too. A built C-4 can take highly modified small blocks putting out over 500hp without a problem. Since you're running an FE block, I don't know if you would have had many options to even use the C-4 had you wanted to.