Twin trannies

[ricochet]

No, not from the lost weekend in Bangkok!

Over the last year or so I've scored two transmissions for use in the 73 ironheads I've been messing with.  Looking at what's available for info in the service manual leaves much to be desired as far as what gear ratios go with what gears and years.  So I'm trying to ID what here for gearing in order to decide which one to use where.  Either for a stock engine or a 74" stroked engine both going into stock like chassis.  Here's the two choices laid out from gear tooth count.  Both look to be in great shape like little miles or any wear.

1st,  this one is loaded with all Andrews Products gears and the counts are as follows:  Starting at the trap door on the mainshaft 18, 23, 20, 27. Countershaft is 26, 20, 23, 16.

2nd,  Starting at the trap door on the mainshaft 17, 23, 20, 27. Countershaft is 27, 20, 23, 17.  This one also has a 22 chain sprocket attached to it.

So, what do I have and which is best suited for the stroker?  Manual only states the ratios and what years applicable to.  Seems to be a ratio change progression from 70 through 73 ans later.  Why?

ricochet

[nibroc]

that's a no brainer for me--i'd go with the 1st and try the 22 sprocket; if not high enough put a 23 on it

[ricochet]

Yea,  I was quite surprized when looking over the two trannies that this one was all Andrews gears.  Both trannies looked like new but the one had either AP or Andrews on each gear depending on size.

Still curious on what the rations are or how to figure them.

ricochet

[Maddog]

sounds like the Andrews is the close ratio one  some place here i have some info on them,,   will try an find it