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#1 |
Registered User
Join Date: May 2000
Location: Flin Flon, Manitoba, Canada
Posts: 8,855
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Would there be any benefit to this??
I am looking at swapping out the original 3 speed for a SM465. This tranny has the granny low speed, and I wanted to know if it would a damn bit of difference in driving. Seems to me, I might be better off stickin with my 3 speed.
Need info guys. Thanks
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My name's Tim and I'm a truckaholic My 56 Chevy shop truck build http://67-72chevytrucks.com/vboard/s...d.php?t=562795 |
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#2 |
L.E.D. Tail lights, Baby!
Join Date: Jan 2002
Location: Corona, Ca
Posts: 290
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Why are you considering the swap. I have the 4 spd w/granny, and don't like the fact I get around 8 mpg, and can't go very fast. I am replacing the rear differential gears. That way i keep the original Tranny, and get the benefits of having a cruiser.
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Prov 3:5-8 "Hook 'em" L.E.D. Taillights for sale NOW!!! If interested, visit: www.earlyclassic.com or our website: www.jmcled.com All 67-72 GM Taillights are on sale untill 5 p.m. on Dec 15th, with Guaranteed Christmas delivery! joel.mcwaters@jmcled.com |
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#3 |
Recovering Truck Driver
Join Date: Mar 2002
Location: Orleans, NE USA
Posts: 1,883
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the only benefit to the 4 speed would be the low gear, for taking off easier and for pulling a trailer if you do that at all......the high gear will be the same....1:1 is 1:1, don't matter what tranny you have.
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67 K-20 350, SM465, Eaton rear, 4.56 no spin option 00 Dodge 2500 4x4, 24V cummins, 5 speed Chad South Central Nebraska |
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#4 |
Senior Member
![]() Join Date: Jun 2000
Location: Texan in Iowa
Posts: 2,522
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The only gear you'd gain by that swap is a gear that is not used in everyday driving. It's just for towing/hauling/stump pulling. Sure, it comes in handy to have starting from a standstill on a hill and stuff like that but you can do without it just fine. The other three gears are pretty close to same ratios. Drive is drive is 1:1, so there's no difference in highways RPMs.
What you do get is a floor shifter, which I think is pretty cool and worth something. ![]()
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Ben '68 Chevy C10 Custom LWB 327/TH400 2nd owner '16 GMC Sierra 1500 SLE Dblcab 4wd 5.3 |
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#5 |
Registered User
Join Date: Jun 2000
Location: Bismarck, ND
Posts: 4,285
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I like my CH465. I do use the granny gear once and a while for heavy hauling or parking if I just want to let the engine idle and creap along. I've heard the 465 is alot heavier than the 3 speeds. I don't know if it'd be worth the effort unless you have the truck torn apart anyway.
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Unrestored 68 C-10 CST. Original 327. 4-Speed CH465. 50k or so miles. TREASURER, Drum Brake Club. |
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#6 |
Registered User
Join Date: Dec 1999
Location: Austin, TX, USA
Posts: 7,721
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Factory 4 speed trucks came with a high hump cab. You might have to "modify" your floor pan for clearance issues. The granny gear is the next best thing to 4 wheel drive since it lets you very closely modulate power and wheel spin. When combined with limited slip, lets you drag a boat up a ramp with virtually zero wheel slippage.
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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 |
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#7 |
Registered User
Join Date: May 2000
Location: Flin Flon, Manitoba, Canada
Posts: 8,855
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OK, lets just scrap the whole 4 speed question and move onto another.
What is the best rear end gear ratio for a daily driver. It will be driven on the highway at 100 kph and around town. I currently have 3:07 with the inline 6 and 3 spd. I don't have a tach on the truck but would almost be afraid to see how high the rpm is at highway speed. The engine will be a mildly built 350.
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My name's Tim and I'm a truckaholic My 56 Chevy shop truck build http://67-72chevytrucks.com/vboard/s...d.php?t=562795 |
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#8 |
Senior Member
![]() Join Date: Mar 2000
Location: Saskatoon,SK,Canada
Posts: 2,476
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Tim,
For daily driving without an overdrive tranny the 3.07 is probably the best with a mild V8. A 3.73 is alot more fun though and if you get an overdrive tranny the 3.73 is real nice. If your truck came as a 6 cyl and still has the original diff in place I'd bet it is a 3.73. If you want to put another set of gears in an existing diff a 3.42 would be a good compromise.
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Saskatoon, Saskatchewan Canada |
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#9 |
its all about the +6 inches
Join Date: Jan 2001
Location: Hilliard Ohio
Posts: 2,693
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It's more than just the weight though, there is also mechanical leverage there too.
If it is mostly freeway driving, tall tires will help, but, they will hurt your take off too though. |
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#10 |
Registered User
Join Date: May 2000
Location: Flin Flon, Manitoba, Canada
Posts: 8,855
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The only highway travel that will be done , is to the cabin and back. Which is only about 10 miles away. The rest of the time will be spent cruising around. The tires I have on there are 235 75 R15 all seasons. I am still going to use this truck for hauling anything I need , and will be staying with actual truck tires. I like the look of low profile tires, but for the purpose my truck is used for, I don't think they would hold up. Thanks for all the replies guys
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My name's Tim and I'm a truckaholic My 56 Chevy shop truck build http://67-72chevytrucks.com/vboard/s...d.php?t=562795 |
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#11 |
Registered User
Join Date: Dec 1999
Location: Austin, TX, USA
Posts: 7,721
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The 3.42 would be the best probably, but they are not very common... With such short road trips, I would go for the 3.73 and 28-30" tall tires. I have 265 75 16 on my truck with 3.54 gears. They are 30.5" tall, about the same as a 31 10.5 15. More gear around town might actually help your mileage.
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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 |
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