Cast iron c6 tail shaft

[loman]

I have a spare big block C6 I picked up a while back and it has a cast iron tail shaft. Someone told me that a cast iron tailshaft would indicate a CJ transmission. I did some searching and I think the numbers are right but I'm not convinced it is a CJ. The numbers on the tailshaft are RF 080P 7A040-A. I don't remember what servo was on it, but it wasn't the R servo. Things could have been changed over the years, but I purchased it from a guy who was working on a Mustang. I would think he would have known what it was and not sold it so cheap if it was a CJ. What else can I look for to help identify this trans?

[poboyjo65]

That would be a good one for boss cyclone,,,but he is awol.

[vicegrip]

Which big block? Reread the number. If it actually reads C80P,it probably is a CJ,SCJ. Depending on the casting date,could be correct for 428,429 Cobra Jet. If it's on a trans that came with it orig,it will have extra clutches. It should have the R servo but they were often removed before they became available after market.Other than the resto deal,no real perf upgrade over alum.