Vacuum/Mechanical Advance Dilemma SB340

10 inch high stall converter, factory is 11 inch. Sounds like it needs gears, and a lot lower than 3.55. But run a compression test. With detonation coming in that quickly I would be highly suspicious.

YES! I was running a peg leg 271 when I did. I just got my Suregrip 3:55 and need to get that in my 8-.25 ASAP! Next on the list actually.