3.08:1 in K10

[JohnnyPopper]

I looked into swapping out the TH350 to a OD, move the cross member, etc, north of 2-2.5K

Had the brainiac idea to change out the Diff from 3.73 to a 3.08

I know there is a mid point, what 3.48? but I don't think I would see much difference.

It's a daily, I don't offroad, I don't haul loads, just don't like doing 3-3500 rpm to keep up with traffic.

While here, does anyone know the max torque rpm for a crate Goodwrench 350?

I'm first to admit that I don't know how far down the rpm will drop, so if this is a fools errand, please flame away!

[VileZambonie]

Keep the 3.73:1 and change to a 700R4

[JohnnyPopper]

Thx VZ, that's what I think the ultimate solution is.

I faintly recall a comment about there being a year range where that trans was bad-is that on your radar?

[VileZambonie]

87 up are the best years but that was 33 years ago so, finding a good used one is just a bad gamble. Buy a reman unit, they come with 3-4 year warranty

[JAH]

I'm a "deep gear" guy.  While I don't think that most folks need something like 4.88s or 4.56s, I would probably never go any higher than 3.73s on anything with body-on-frame construction.  For me, it's not a hauling or offroading thing.  It's an enjoyable driving experience thing.  My Mom has a 2008 Tahoe with the small LS and high gears.  It's a great and reliable vehicle.  Unfortunately, with the really small V-8 and highway gears, it'll barely get out of its own way.  Nothing even starts happening 'til about 3000 RPM.

I agree with you on the 3.73 versus 3.42 thing.  I don't know that you'll be able to tell a difference.  I have two '86 K30s, one with 4.10s and the other with 3.73s.  Both get the same fuel mileage (give or take a tenth or two of a gallon, here or there).  And, the only time I can tell a difference is when there's a load behind them.  Other than that, they feel pretty-much identical.

I was in my teens in the 80s.  And, my mind has never relinquished the thought of the 700R4 being a turd.  So, to answer your question, if something is engrained in my head that deep, there must've been a few years that were less than desirable.

My only experience with the 350 was knowing of a guy who made about 300-325 ft/lbs. with the Goodwrench 350.  I believe he was running a Quadrajet.  If I remember correctly,...and don't quote me on this...I think it was way up there, like in the 3500 to 3800 RPM range.

[JohnnyPopper]

Just Curious: Can anyone state what the rpm would be between differentials in a 3.73, 3.48, or 3.08:1? Sorry for the ignorance, I was never schooled on this discipline.

[zieg85]

https://purperformance.com/p-29669-rpm-calculator.html

[fitz]

I was in my teens in the 80s.  And, my mind has never relinquished the thought of the 700R4 being a turd.  So, to answer your question, if something is engrained in my head that deep, there must've been a few years that were less than desirable.

My thoughts exactly.
I know I'm a little late responding to this (sounds like JohnnyPopper is already involved with the gear swap).
I know technology has come along way since the 80's.  Like Vile said, some 700R4's come with a great warranty now, but my mind is still stuck in the past.
  Some will cringe at this, but in the early 90's I replaced my 700R4 in my 88 Jimmy with a turbo 350.  The 700R4 was due for its 3rd rebuilt and I said enough is enough.