250/overdrive/what gears? - The 1947 - Present Chevrolet & GMC Truck Message Board Network

**special-K** · 08-08-2007, 07:50 AM

I want to built a truck for economy.It`ll be a shortbed with a 250-6 and 4L60E or 700r4.I`m wondering what gear ratio I should go with to keep it up in o/d but be as high as possible for mileage.Too high gears around town can dog your mileage.I may go with a manual overdrive which will give more control,but I`d want it to be able to stay in o/d as much as expected going up hills.
has anyone played with this idea or had any actul experience with doing this?My thoughts are the 3.08s are out.Maybe 3.42s,or do I need 3.73s?

Bus Ted Knuckle · 08-08-2007, 08:38 AM

I have been real happy with 3.73's in my trucks set up like you are talking about.

mvfd70 · 08-08-2007, 10:06 AM

I'm using my 250 and going to put in a later model 5 speed transmission. Either a T-5 or a NV3500. I'm going to start out with my original 3.73's. I've heard they work pretty well for an overdrive set up.

Willy Prost · 08-08-2007, 12:09 PM

I have 3.73 with the Tremec TKO 5-speed.

Unless you live in a land of no hills, I think a 3.42 rear would mean that you wouldn't use the OD very much without lugging the motor.

**special-K** · 08-08-2007, 12:31 PM

That`s what I`m wondering.These trucks didn`t have 3.42s,right?It`s not that much taller than 3.73.I know that with 4.10s and o/d a truck is very hiway friendly compaired to w/o o/d.So,3.73 would be better and help keep some grunt still.Maybe 3.42s would be good with a 283 or 292.

2bits · 08-08-2007, 04:04 PM

Well, you said you wanted to build it for economy, my Stepside with a 250 l6 in it has 2:72 gears and it runs great. Depends how much freeway driving you do, I have a 45 min commute to work, so I wanted to maximize as much as I could with what I had. I wish I could drop a 4 speed in!

**special-K** · 08-08-2007, 06:32 PM

Quote:

Originally Posted by 2bits

Well, you said you wanted to build it for economy, my Stepside with a 250 l6 in it has 2:72 gears and it runs great. Depends how much freeway driving you do, I have a 45 min commute to work, so I wanted to maximize as much as I could with what I had. I wish I could drop a 4 speed in!

What trans do you have,now.Do you have o/d?I`d go taller gears if I wasn`t going o/d.

Longhorn Man · 08-08-2007, 06:19 PM

Tim, I'd go with the 3.73 personally.
there were no 3.42s in these trucks.

powell72 · 08-08-2007, 06:35 PM

If it helps you any special, I turn 2500 RPM's at 70 MPH with my 700R4 with 3.73's and 275/60/15's.

**special-K** · 08-08-2007, 06:41 PM

Yeah,that helps...thanks.

bad6772 · 08-08-2007, 07:06 PM

id run good ole 4.56s lol . forget the gas milage

Longhorn Man · 08-08-2007, 07:21 PM

and in all reality, you can do 2500 RPM at 65 with 3.07 gears, and spend a WHOLE lot less money.

Brad · 08-10-2007, 07:25 PM

Quote:

Originally Posted by Longhorn Man

and in all reality, you can do 2500 RPM at 65 with 3.07 gears, and spend a WHOLE lot less money.

Andy, I tried this once and although it worked- it wasn't ideal. The problem was that with that gearing, I had to use more clutch in 1st gear and it had a slow take off as a result. It'll work for a guy on a budget, but I didn't like it.

Scott68-93-97 · 08-10-2007, 07:30 PM

If you run the 700r4 run 3.08 gears due to the low first gear in the 700 its like having a th350 with 3.73, or run 3.42 dont worry if they didn't originally come in that truck neither did the tranny your gonna put in.

**special-K** · 08-08-2007, 09:21 PM

Yeah,I bet a 250/4speed(like M-21s etc)/3.08s would bean economical combo.I`d want a 4spd for starting off and better range.

2bits · 08-09-2007, 02:35 PM

I have a new 400 behind the 250. People usually think that's crazy, but the 400 has taller 1st and 2nd gears so it helps acceleration not robs it, and when it reaches 1=1 in 3rd gear, the highway gears helps bring the RPMS down there.

I just had the tranny rebuilt when I had the V8 in it, so I can't justify to myself pulling it out right now when I have so much other to do

later on I plan on a 200 R4 (built right) for an easy swap.

BCOWANWHEELS · 08-09-2007, 04:57 PM

i think a 250, nv4500 & 3.73 gears would be the nuts for towing in city and highway driveing myself. i know my 250 with a 3 speed & stock 235r15 tires dont like highway speeds of over 65 mph. also it could use a lower 1st gear when loaded too for takeoff and loaded reverse also.
bob

**special-K** · 08-10-2007, 06:15 AM

Yeah,I don`t want that high geared roll-off from a 3spd.I prolly will try to find a New Venture trans.

**special-K** · 08-10-2007, 09:52 PM

I`m not worried about the 3.42s being non-original.I think 3.08s will be too high,I know 3.73 would do(w/any trans),and I wonder if 3.42s would do since they are between those other two.If they aren`t too high,that`s what I hoped to use.I even have a 3.42 posi.

08-08-2007, 07:50 AM	#1
special-K Special Order Join Date: Nov 2004 Location: Mt Airy, MD Posts: 85,851	250/overdrive/what gears? I want to built a truck for economy.It`ll be a shortbed with a 250-6 and 4L60E or 700r4.I`m wondering what gear ratio I should go with to keep it up in o/d but be as high as possible for mileage.Too high gears around town can dog your mileage.I may go with a manual overdrive which will give more control,but I`d want it to be able to stay in o/d as much as expected going up hills. has anyone played with this idea or had any actul experience with doing this?My thoughts are the 3.08s are out.Maybe 3.42s,or do I need 3.73s? __________________ "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 ~

08-08-2007, 08:38 AM	#2
Bus Ted Knuckle Son of a gun Join Date: Jan 2007 Location: Hot Springs, Arkansas Posts: 1,636	Re: 250/overdrive/what gears? I have been real happy with 3.73's in my trucks set up like you are talking about. __________________ Bill BEATERS ARE NEATER

08-08-2007, 10:06 AM	#3
mvfd70 Registered User Join Date: Jan 2007 Location: Opdyke, IL Posts: 775	Re: 250/overdrive/what gears? I'm using my 250 and going to put in a later model 5 speed transmission. Either a T-5 or a NV3500. I'm going to start out with my original 3.73's. I've heard they work pretty well for an overdrive set up. __________________ 1978 Chevrolet Silverado 3/4 ton 400 small block. 2000 F-250 Powerstroke 2002 GMC Yukon Denali XL

08-08-2007, 12:09 PM	#4
Willy Prost Senior Member Join Date: Jan 2000 Location: Arlington, VA Posts: 398	Re: 250/overdrive/what gears? I have 3.73 with the Tremec TKO 5-speed. Unless you live in a land of no hills, I think a 3.42 rear would mean that you wouldn't use the OD very much without lugging the motor.

08-08-2007, 12:31 PM	#5
special-K Special Order Join Date: Nov 2004 Location: Mt Airy, MD Posts: 85,851	Re: 250/overdrive/what gears? That`s what I`m wondering.These trucks didn`t have 3.42s,right?It`s not that much taller than 3.73.I know that with 4.10s and o/d a truck is very hiway friendly compaired to w/o o/d.So,3.73 would be better and help keep some grunt still.Maybe 3.42s would be good with a 283 or 292. __________________ "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 ~

08-08-2007, 04:04 PM	#6
2bits Registered User Join Date: Jan 2006 Location: Dallas Posts: 504	Re: 250/overdrive/what gears? Well, you said you wanted to build it for economy, my Stepside with a 250 l6 in it has 2:72 gears and it runs great. Depends how much freeway driving you do, I have a 45 min commute to work, so I wanted to maximize as much as I could with what I had. I wish I could drop a 4 speed in! __________________ _______________ Thomas '78 Silverado '74 Monte Carlo '47 Teardrop Trailer East Texas Classics Local Club

08-08-2007, 06:19 PM	#8
Longhorn Man its all about the +6 inches Join Date: Jan 2001 Location: Hilliard Ohio Posts: 2,690	Re: 250/overdrive/what gears? Tim, I'd go with the 3.73 personally. there were no 3.42s in these trucks.

08-08-2007, 06:35 PM	#9
powell72 Senior Member Join Date: Jan 2005 Location: Loveland Co. Posts: 3,098	Re: 250/overdrive/what gears? If it helps you any special, I turn 2500 RPM's at 70 MPH with my 700R4 with 3.73's and 275/60/15's. __________________ Chris 74 Custom Deluxe SWB 350/350/3.73’s 99 2wd Silverado RCSB 5.3/4L60/3.90’s http://www.classictrucks.com/feature...short_bed.html Last edited by powell72; 08-08-2007 at 06:35 PM.

08-08-2007, 06:41 PM	#10
special-K Special Order Join Date: Nov 2004 Location: Mt Airy, MD Posts: 85,851	Re: 250/overdrive/what gears? Yeah,that helps...thanks. __________________ "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 ~

08-08-2007, 07:06 PM	#11
bad6772 Official Site Guitar Shredder Join Date: May 2006 Location: Oz Posts: 3,955	Re: 250/overdrive/what gears? id run good ole 4.56s lol . forget the gas milage

08-08-2007, 07:21 PM	#12
Longhorn Man its all about the +6 inches Join Date: Jan 2001 Location: Hilliard Ohio Posts: 2,690	Re: 250/overdrive/what gears? and in all reality, you can do 2500 RPM at 65 with 3.07 gears, and spend a WHOLE lot less money.

08-10-2007, 07:30 PM	#14
Scott68-93-97 Registered User Join Date: Jul 2006 Location: Fair Oaks, CA Posts: 475	Re: 250/overdrive/what gears? If you run the 700r4 run 3.08 gears due to the low first gear in the 700 its like having a th350 with 3.73, or run 3.42 dont worry if they didn't originally come in that truck neither did the tranny your gonna put in. __________________ 1968 Short Fleet 350/700r4 http://67-72chevytrucks.com/vboard/s...d.php?t=249435 1997 Bagged XtdCab Vortec350/4L60e http://67-72chevytrucks.com/vboard/s...44#post2286144 1993 XtdCab Longbed 4x4 6.5Turbo/NV4500 "Daily Driver" 1985 Toyota XtdCab 4x4 22re/W-56/Dual T-cases, Doug Thorley Header, Homebrew front and rear spring packs, Tons of Mods to suspension and drivetrain, 35" boggers, coming soon ARB's and 5.29's, Possible 4.3/700r4 swap

08-08-2007, 09:21 PM	#15
special-K Special Order Join Date: Nov 2004 Location: Mt Airy, MD Posts: 85,851	Re: 250/overdrive/what gears? Yeah,I bet a 250/4speed(like M-21s etc)/3.08s would bean economical combo.I`d want a 4spd for starting off and better range. __________________ "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 ~

08-09-2007, 02:35 PM	#16
2bits Registered User Join Date: Jan 2006 Location: Dallas Posts: 504	Re: 250/overdrive/what gears? I have a new 400 behind the 250. People usually think that's crazy, but the 400 has taller 1st and 2nd gears so it helps acceleration not robs it, and when it reaches 1=1 in 3rd gear, the highway gears helps bring the RPMS down there. I just had the tranny rebuilt when I had the V8 in it, so I can't justify to myself pulling it out right now when I have so much other to do later on I plan on a 200 R4 (built right) for an easy swap. __________________ _______________ Thomas '78 Silverado '74 Monte Carlo '47 Teardrop Trailer East Texas Classics Local Club

08-09-2007, 04:57 PM	#17
BCOWANWHEELS Registered User Join Date: Nov 2006 Location: KINGSPORT,TN. Posts: 3,035	Re: 250/overdrive/what gears? i think a 250, nv4500 & 3.73 gears would be the nuts for towing in city and highway driveing myself. i know my 250 with a 3 speed & stock 235r15 tires dont like highway speeds of over 65 mph. also it could use a lower 1st gear when loaded too for takeoff and loaded reverse also. bob __________________ I BELIEVE IN JOHN 3:16



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08-10-2007, 06:15 AM	#18
special-K Special Order Join Date: Nov 2004 Location: Mt Airy, MD Posts: 85,851	Re: 250/overdrive/what gears? Yeah,I don`t want that high geared roll-off from a 3spd.I prolly will try to find a New Venture trans. __________________ "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 ~

08-10-2007, 09:52 PM	#19
special-K Special Order Join Date: Nov 2004 Location: Mt Airy, MD Posts: 85,851	Re: 250/overdrive/what gears? I`m not worried about the 3.42s being non-original.I think 3.08s will be too high,I know 3.73 would do(w/any trans),and I wonder if 3.42s would do since they are between those other two.If they aren`t too high,that`s what I hoped to use.I even have a 3.42 posi. __________________ "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 ~

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