FJ60 H42F on 31's: how to get a high final drive ratio and decent highway rpms

[Hawkspring]

So- new to FJs and have been reading and planning. I would like to keep highway cruise rpms around 2700 but up my crawl ratio. So far the solution I am finding seems ridiculous and expensive. I want to keep RPMs reasonable at 65, and get my low range final drive much higher than stock.
Using grimms calculator:
As it sits: 3.70 gears, h42f, 31" tires= 30:1 2700rpms at 65
First idea: 4.56, h42f, 31" tires=37:1 3200rpms at 65. Too high!
Overnoard idea: 4:56, h55f, 31" tires=50:1 2700rpms at 65.
Crazy level: add the AA t case, 4:56, and h55f!

No clue how the advance adapters 3:1 and 8% overdrive would affect either setup. But it seems like a big pile of parts and dollars to get to a fairly conservative crawl ratio. What am I missing? Any ideas?

 

[dbleon]

Um you pretty much got it. Can't have both worlds without paying for it...

 

[Hawkspring]

Am I reading right that the marlin toybox is not in production for either the 4 or 5 spd?

 

[Output Shaft]

H55F tranny w/ 4:11 diff gears will get you where you want to be... (the poor house)

 

[GeologistFelix]

Another option: H41 and keep your gears the same.

First gear ratio is about the same as an H55 (4.95 I wanna say?), but it's only got four gears. The spacings are slightly wider than the H42, otherwise. They never sold in the US, but a fair number get imported, used, and even from somewhere pricey like Spectre Offroad, they sell for $600-900. Otherwise, I'd say to get 4.11 gears and just drive 60 instead of 65 on the highway for 2700 rpms.

With the H41, though, that gets you a crawl ratio of about ~42:1 in first gear, 4-lo. With that 1st gear, you could go to 4.11 gears and 33" tires and still run about the same highway RPMs and have a 46:1 crawl ratio.

 

[enfield]

"Too high!"

Reminded me of this, lol

 

[GarethsSixty]

In Oz back in the 80's and early 90's you could get a fairey overdrive, occasionally you see them on ebay
theres a few pics and threads on mud on them, but they are getting harder to find, as they havent been made for a long time