The 1947 - Present Chevrolet & GMC Truck Message Board Network







Register or Log In To remove these advertisements.

Go Back   The 1947 - Present Chevrolet & GMC Truck Message Board Network > General Truck Forums > All 4x4 Tech & Off Roading

Web 67-72chevytrucks.com


Reply
 
Thread Tools Display Modes
Old 12-17-2010, 02:03 PM   #1
K20-69-POS
Registered User
 
Join Date: Sep 2010
Location: state college, pa
Posts: 86
Gearing w/35s

Would 4.56 gears with an sm465 and an NP205 (all in a 1969 K20 with a 292) be too tall of gears (33-35" tires)?

*The truck will never be driven on the highway, only in off road situations and the occasional towing of a boat 40 miles on back roads. It might take one 200 mile trip to the outerbanks.
__________________
'69 K20 292 4spd 4x4 - project 27,000 orig. miles
'98 1500 suburban 4x4 - driver 219000 orig. miles
K20-69-POS is offline   Reply With Quote
Old 12-17-2010, 02:37 PM   #2
Altec
Getcha Pull
 
Altec's Avatar
 
Join Date: Nov 2010
Location: MD
Posts: 691
Re: Gearing w/35s

Quote:
Originally Posted by K20-69-POS View Post
Would 4.56 gears with an sm465 and an NP205 (all in a 1969 K20 with a 292) be too tall of gears (33-35" tires)?

*The truck will never be driven on the highway, only in off road situations and the occasional towing of a boat 40 miles on back roads. It might take one 200 mile trip to the outerbanks.
A 4.56 should be good for you with the uses you listed. If you said highway use, I'd go with a 4:11.

Since first is 3.58 on the 465 compared to the 2.48 of the 400, and 2.52 of the 350 you can get away with a slightly smaller gear without overly negative effects.

I'm building a truck with a 465, and 35" tires myself, and am going to be using 3.42 gears. Partly because it is what I have laying around... Also because I want to do more highway. I'm just going to get my extra reduction out of the T-Case when needed. Not ideal, but eh.
__________________
'81 K10 454/SM465
'86 S10 Blazer
'95 H-D Softail
'96 Integra
Altec is offline   Reply With Quote
Old 12-17-2010, 05:41 PM   #3
K20-69-POS
Registered User
 
Join Date: Sep 2010
Location: state college, pa
Posts: 86
Re: Gearing w/35s

Roger that, I was going through your build thread and I gotta ask- How long did it take to wire wheel your frame?
__________________
'69 K20 292 4spd 4x4 - project 27,000 orig. miles
'98 1500 suburban 4x4 - driver 219000 orig. miles
K20-69-POS is offline   Reply With Quote
Old 12-17-2010, 06:26 PM   #4
Altec
Getcha Pull
 
Altec's Avatar
 
Join Date: Nov 2010
Location: MD
Posts: 691
Re: Gearing w/35s

Well, I only had to do about from the tranny crossmember back. In front of that had a nice oil/grease coating to keep it from rusting. Without the bed in the way though, I'd say it took me about a hour, maybe a hour and a half. Didn't really time it. The frame mainly had surface rust. Cleaned up easy.
__________________
'81 K10 454/SM465
'86 S10 Blazer
'95 H-D Softail
'96 Integra
Altec is offline   Reply With Quote
Old 12-17-2010, 10:30 PM   #5
Mike C
Registered User
 
Mike C's Avatar
 
Join Date: Dec 1999
Location: Austin, TX, USA
Posts: 7,713
Re: Gearing w/35s

I think you meant 2nd is 3.58 in the SM465? Although now that I think about it, the 80's trucks listed 1st as L and 2nd as 1st? Either way, the SM465 gives you plenty of gear with it's granny gear.

4.56 and 35's is a great choice for a truck that never sees the far side of 60.
__________________
44 Willys MB
52 M38A1
64 Corvette Coupe
68 Camaro 'vert LT1 & TH700
69 Z/28 355 12.6's @110
69 Chevy Short Step 4 1/2"/7" drop
72 Jimmy 4WD 4spd 4" & 35's
02 GMC 2500HD 4x4 Duramax
Mike C is offline   Reply With Quote
Old 12-18-2010, 02:10 AM   #6
Altec
Getcha Pull
 
Altec's Avatar
 
Join Date: Nov 2010
Location: MD
Posts: 691
Re: Gearing w/35s

Quote:
Originally Posted by Mike C View Post
I think you meant 2nd is 3.58 in the SM465? Although now that I think about it, the 80's trucks listed 1st as L and 2nd as 1st? Either way, the SM465 gives you plenty of gear with it's granny gear.

4.56 and 35's is a great choice for a truck that never sees the far side of 60.
Yes, sir. The "First" gear in the muncies is a unsynchronized low-range. Not really practical for every day driving. And split between L-1 is terrible (6.55 Low). Most people consider the gap in 1-2 bad. Haha.
__________________
'81 K10 454/SM465
'86 S10 Blazer
'95 H-D Softail
'96 Integra
Altec is offline   Reply With Quote
Old 12-18-2010, 02:23 AM   #7
swamp rat
Registered User
 
swamp rat's Avatar
 
Join Date: Oct 2007
Location: Spanaway
Posts: 8,451
Re: Gearing w/35s

I have a 350/350/np205 combo and 3:73 gears, i went to 33's back around 93' and i'm pretty glad i didn't buy 35's, its a bit labored off the line, but low rpm's on the freeway. I often wanted to go to 4:11's but could mever come up with the justification on spending the coin.....yet
__________________
Mike.

Swamp Rat build thread :
http://67-72chevytrucks.com/vboard/s...d.php?t=595019

72 3/4T 4X4
4" BDS Lift
33" BFG's
swamp rat is offline   Reply With Quote
Old 12-18-2010, 09:04 AM   #8
special-K
Special Order

 
special-K's Avatar
 
Join Date: Nov 2004
Location: Mt Airy, MD
Posts: 85,863
Re: Gearing w/35s

On that 4.56:1 truck,that came with 7.50-16s originally,by going to 35s you'll end up with right about 4.10:1 at the road/ground.It's a good ratio,especially with a 4spd.I like 4.10s with 35s because I'm on the road way more than 4 wheelin.With that you end up with right about 3.73s running 35s.I do fine off road with that.
__________________
"BUILDING A BETTER WAY TO SERVE THE USA"......67/72......"The New Breed"

GMC '67 C1500 Wideside Super Custom SWB: 327/M22/3.42 posi.........."The '67" (project)
GMC '72 K2500 Wideside Sierra Custom Camper: 350/TH350/4.10 Power-Lok..."The '72" (rolling)
Tim

"Don't call me a redneck. I'm a rough cut country gentleman"

R.I.P. ~ East Side Low Life ~ El Jay ~ 72BLUZ ~ Fasteddie69 ~ Ron586 ~ 67ChevyRedneck ~ Grumpy Old Man ~
special-K is offline   Reply With Quote
Reply

Bookmarks


Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT -4. The time now is 02:12 PM.


Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2024, vBulletin Solutions Inc.
Copyright 1997-2022 67-72chevytrucks.com