Highway Speeds - The 1947 - Present Chevrolet & GMC Truck Message Board Network

Frijolito1988 · 09-11-2012, 11:09 PM

Hey guys. I though maybe we could start a thread with our drive train combos and highway cruising speeds and RMP's.

I have a 68 and 67 and my main use for these trucks would be car show's / cruises not realy interested in going crazy fast or drag strips. I know alot of these trucks are revving to high heaving when going past 70 when idealy it would awsome to be cruising at 70-80 MPH at 23-2500 RMP

Right now on the 67

67 SWB , I6 250 , Saginaw 4 speed , 3.08 rear end going 2500 @ 75

If you guys can post up the

- Truck type

- Engine

-Tranny

-Rear end gears

-Height of rear tires

and the RPM's when going 70-75 MPH..

Thanks!

GuyO · 09-11-2012, 11:39 PM

70 GMC SWB
327 ci
200-4R
3.73 posi
29" (235/75R15)
2200 RPM & 70 MPH

Frijolito1988 · 09-12-2012, 01:09 AM

Great crusing range. Havent really heard of that tranny though.

RustyBucket · 09-12-2012, 01:29 AM

'72 Blazer 2wd.
454+.30
Tremec TKO500
3.08 rear
30" 295/50/18
2000 RPM @ 80mph

PAWS 72 · 09-12-2012, 01:56 AM

72 c-10
350
350 turbo
3:08 gears
29" 255-70-15
2200@60 mph
10 mpg

AusTx68 · 09-12-2012, 09:19 AM

Quote:

Originally Posted by PAWS 72

72 c-10
350
350 turbo
3:08 gears
29" 255-70-15
2200@60 mph
10 mpg

Hey PAWS, your setup has you running 2200 @ 60 mph? I would have figured a much lower RPM.

1972RedNeck · 09-12-2012, 11:06 PM

Quote:

Originally Posted by RustyBucket

'72 Blazer 2wd.
454+.30
Tremec TKO500
3.08 rear
30" 295/50/18
2000 RPM @ 80mph

What do you get for mileage?

RustyBucket · 09-13-2012, 12:54 AM

Quote:

Originally Posted by 1972RedNeck

What do you get for mileage?

It'll give 15mpg @ 75mph. BUT, it's LOTS more fun blasting around with the secondaries open in the lower gears.
Vac. 750 Holley, performer RPM, low compression, peanut ports, mild hydraulic cam. Runs good on 87 octane.

GASoline71 · 09-12-2012, 09:29 AM

Quote:

Originally Posted by Frijolito1988

Great crusing range. Havent really heard of that tranny though.

The TH200-4R came behind the engines in the GM "G" bodies. Great overdrive transmission. Can be built to handle big HP and TQ numbers. Not as plentiful as the TH700-R4... but I believe is a better tansmission. Especially if you can find one that came out of a Buick Grand National.

Gary

PAWS 72 · 09-12-2012, 10:42 AM

That's with pencil and paper.I can runaround 55 or56 and get about 13 to 14 thou. I'm thinking it mat be gas addidtives.I know my Nissan Quest has dropped also. I have tried different places but not enuff difference in mileage.

I ran my fuel line in the stock location and then my mileage dropped last year, do you think the heat from motor has caused the difference?

And that's with a new Sun tach

**med.bronze** · 09-12-2012, 12:21 PM

'71 k10 lwb
350
sm465
3.73 w/posi
33's running at 2800 at 70
mine feels most comfortable at 60

AusTx68 · 09-12-2012, 01:00 PM

Quote:

Originally Posted by PAWS 72

That's with pencil and paper.I can runaround 55 or56 and get about 13 to 14 thou. I'm thinking it mat be gas addidtives.I know my Nissan Quest has dropped also. I have tried different places but not enuff difference in mileage.

I ran my fuel line in the stock location and then my mileage dropped last year, do you think the heat from motor has caused the difference?

And that's with a new Sun tach

Hey PAWS I was talking about your RPM. With 3:08 gears I figured you'd be running a lower RPM at 60 mph. Maybe I've been in 700r4 world too long

Frijolito1988 · 09-12-2012, 01:19 PM

Quote:

Originally Posted by AusTx68

Hey PAWS I was talking about your RPM. With 3:08 gears I figured you'd be running a lower RPM at 60 mph. Maybe I've been in 700r4 world too long

Thats what i was thinking. With those 3.08 I would have guessed 2500 at around 70 ish or more .

**special-K** · 09-12-2012, 04:58 AM

1972 K2500
350
TH350
4.10:1
235/85-16
12.5 mpg
Pretty much as built from factory and driven as designed...drive right on down the hiway at hiway speeds,just like they did in the '70s when no one had overdrive and didn't worry about rpms going over 3,000. I think at 65 I am right about 3,000. That's the speed I drive...even in my newer truck with o/d.

grancuda · 09-12-2012, 08:12 AM

72 C10 Short/Step 2/3 drop
350/holley 600VS
Saginaw 3 speed on column
3:73 gears in a 12 bolt
6" 295-50-15
3150@65 mph
14 mpg

AusTx68 · 09-12-2012, 09:17 AM

68 C-10 SWB
383 ci
700r4
4:11 Eaton posi in 12 bolt
20" wheels
2300 RPM & 70 MPH

jablack · 09-12-2012, 01:03 PM

I've noticed lately the mileage in my 03 burb has dropped. I wonder how much ethanol is in our gas now? They use to post at the pump how much ethanol the gas contained but I haven't seen them posted in some time.

PAWS 72 · 09-12-2012, 11:52 PM

Quote:

Originally Posted by jablack

I've noticed lately the mileage in my 03 burb has dropped. I wonder how much ethanol is in our gas now? They use to post at the pump how much ethanol the gas contained but I haven't seen them posted in some time.

ja that's the reason I got rid of my 08 burb.It was getting about the same as the 72 at 65.Plus after this last back surgery it was a pain to get in. But I loved it. Long and solid black.paws bus. ha

GuyO · 09-12-2012, 01:36 PM

This is the table I used when determining RPM/MPH with a 200-4r and a 29" tire. It didn't paste verywell from Excel it is is based on the overdrive of .67:1 so all figures in the table assume the Torque converter to be locked up in 4th gear. I run a Goodyear Wrangler P235/75r15 whuch is about the same height as the original "H" on the SPID.

Tach GR = gear ratio (3.73 x .67 = 2.499) TFT = Total Feet Travelled at Tach RPM * FT MPH
1000 2.50 3,025.96 34.4
2000 2.50 6,051.91 68.8
2500 2.50 7,564.89 86.0
2800 2.50 8,472.68 96.3
3000 2.50 9,077.87 103.2
3200 2.50 9,683.06 110.0

BlackedOut67shorty · 09-12-2012, 03:50 PM

67 c10 swb
350
turbo 350
3.73
P235/75 R.15
70-75 mph @ 3000-3300 rpm

502ms · 09-12-2012, 08:33 PM

Subscribed. I will capture this and get back to you. I want to be dead on.
I am pondering my next move with my drivetrain (whether it be a 4L80E or a built T56) and something nice in front of it...5.3/6.0 or just a 383 stroker until I get my beloved 572

big_al_71 · 09-12-2012, 08:48 PM

Truck type 71 swb

- Engine small block 400

-Tranny th350

-Rear end gears 373 auburn posi

-Height of rear tires 295.40.20

and the RPM's when going 70-75 MPH.. 2900rpm-3000rpm

cubber · 09-13-2012, 01:43 AM

69 swb stepper
250 I6
TH350
3.42 or 3.08 gear (maybe somebody can tell from this info)
70ish (speedo a little off from gear change) @ 25-2700 rpm
255/70r15 tires
15+ mpg

RustyBucket · 09-13-2012, 10:07 AM

Quote:

Originally Posted by cubber

69 swb stepper
250 I6
TH350
3.42 or 3.08 gear (maybe somebody can tell from this info)
70ish (speedo a little off from gear change) @ 25-2700 rpm
255/70r15 tires
15+ mpg

Cubber, what gear did you change from/to to throw your speedo reading off?
I've got an app. on my phone, SPEED BOX, it's free and it's like havin' a speedometer in your pocket. I wanted to know how fast my golf cart would go.

**LEEVON** · 09-13-2012, 09:42 AM

71 swb
355 heads/cam
700R4 w/ 2200rpm converter
3.73
255/60/15 (28"-ish)
22-2300 RPM at 70mph locked. 2500-2600 unlocked.

This is pretty much the ideal gearing in my opinion, although I prefer to cruise at 65mph. Every truck has an ideal cruising speed, mine is governed by road and wind noise, vibrations, etc.

09-11-2012, 11:09 PM	#1
Frijolito1988 Registered User Join Date: Jul 2010 Location: So Cal Posts: 421	Highway Speeds Hey guys. I though maybe we could start a thread with our drive train combos and highway cruising speeds and RMP's. I have a 68 and 67 and my main use for these trucks would be car show's / cruises not realy interested in going crazy fast or drag strips. I know alot of these trucks are revving to high heaving when going past 70 when idealy it would awsome to be cruising at 70-80 MPH at 23-2500 RMP Right now on the 67 67 SWB , I6 250 , Saginaw 4 speed , 3.08 rear end going 2500 @ 75 If you guys can post up the - Truck type - Engine -Tranny -Rear end gears -Height of rear tires and the RPM's when going 70-75 MPH.. Thanks!

09-11-2012, 11:39 PM	#2
GuyO Registered User Join Date: Nov 2011 Location: Kirkland, WA Posts: 343	Re: Highway Speeds 70 GMC SWB 327 ci 200-4R 3.73 posi 29" (235/75R15) 2200 RPM & 70 MPH

09-12-2012, 01:09 AM	#3
Frijolito1988 Registered User Join Date: Jul 2010 Location: So Cal Posts: 421	Re: Highway Speeds Great crusing range. Havent really heard of that tranny though.

09-12-2012, 01:29 AM	#4
RustyBucket Registered User Join Date: Jul 2009 Location: Space Coast, Fl. Posts: 1,050	Re: Highway Speeds '72 Blazer 2wd. 454+.30 Tremec TKO500 3.08 rear 30" 295/50/18 2000 RPM @ 80mph __________________ Dad always said, "Son, WISH IN ONE HAND, and ......." -------------------------------------- -------------------------------------- Current toy trucks: '71 GMC 1500 SUPER CUSTOM short/step, orig. dk. blue, 350/700r, ps,pb, A/C '72 Blazer 2wd, ochre & white, 454, tremecTKO 500 5spd. ps, pb, A/C, tilt Last 10yrs of hobby vehicles, had a FEW more in the 50yrs. before these: '66 Plymouth Belvedere City of Miami cop car clone. '70 Nova 406"sb, 13.5-1, solid roller, Brodix, p.glide/t.brake, back halved, 9" Ford, spool 4.88, cage,ladder bar/coilover, 10.5 tire....... SOLD!! '67 C10 short/step side mount spare -- SOLD!! '72 Jimmy 2wd, 350/350, ps, pb, fun driver, lots of bondo & a shiny red paint job..... SOLD!! '69 Nova 350, 4spd, A/C, ps, p.b, ...SOLD!!

09-12-2012, 01:56 AM	#5
PAWS 72 Registered User Join Date: Nov 2011 Location: Sheffield, ALA Posts: 2,471	Re: Highway Speeds 72 c-10 350 350 turbo 3:08 gears 29" 255-70-15 2200@60 mph 10 mpg

09-12-2012, 10:42 AM	#10
PAWS 72 Registered User Join Date: Nov 2011 Location: Sheffield, ALA Posts: 2,471	Re: Highway Speeds That's with pencil and paper.I can runaround 55 or56 and get about 13 to 14 thou. I'm thinking it mat be gas addidtives.I know my Nissan Quest has dropped also. I have tried different places but not enuff difference in mileage. I ran my fuel line in the stock location and then my mileage dropped last year, do you think the heat from motor has caused the difference? And that's with a new Sun tach

09-12-2012, 12:21 PM	#11
med.bronze Senior Member Join Date: Dec 2011 Location: Laurel, Mt. Posts: 522	Re: Highway Speeds '71 k10 lwb 350 sm465 3.73 w/posi 33's running at 2800 at 70 mine feels most comfortable at 60 __________________ 1972 Cheyenne Super 10 SWB,bucket seats,dealer cruise,tilt,tac,a/c,shoulder belts, 350/350 1971 K-10 Custom Deluxe 1971 K-10 Custom

09-12-2012, 04:58 AM	#14
special-K Special Order Join Date: Nov 2004 Location: Mt Airy, MD Posts: 85,859	Re: Highway Speeds 1972 K2500 350 TH350 4.10:1 235/85-16 12.5 mpg Pretty much as built from factory and driven as designed...drive right on down the hiway at hiway speeds,just like they did in the '70s when no one had overdrive and didn't worry about rpms going over 3,000. I think at 65 I am right about 3,000. That's the speed I drive...even in my newer truck with o/d. __________________ "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 ~ Last edited by special-K; 09-14-2012 at 09:49 PM.

09-12-2012, 08:12 AM	#15
grancuda Registered User Join Date: Nov 2007 Location: Central OK Posts: 396	Re: Highway Speeds 72 C10 Short/Step 2/3 drop 350/holley 600VS Saginaw 3 speed on column 3:73 gears in a 12 bolt 6" 295-50-15 3150@65 mph 14 mpg

09-12-2012, 09:17 AM	#16
AusTx68 Registered User Join Date: Nov 2008 Location: Italy Posts: 1,278	Re: Highway Speeds 68 C-10 SWB 383 ci 700r4 4:11 Eaton posi in 12 bolt 20" wheels 2300 RPM & 70 MPH __________________ '68 C-10 SWB 383 Stroker (Sold 3/2/2013) '87 R2500 LWB 454 TBI converted to Carb

09-12-2012, 01:03 PM	#17
jablack Classic Chevy Recycler Join Date: Dec 2007 Location: Alabama Posts: 422	Re: Highway Speeds I've noticed lately the mileage in my 03 burb has dropped. I wonder how much ethanol is in our gas now? They use to post at the pump how much ethanol the gas contained but I haven't seen them posted in some time. __________________ 2004 Chevrolet Trailblazer EXT 1970 Chevrolet C50 1979 Chevrolet C30 Need another 67 or 68 soon...

09-12-2012, 01:36 PM	#19
GuyO Registered User Join Date: Nov 2011 Location: Kirkland, WA Posts: 343	Re: Highway Speeds This is the table I used when determining RPM/MPH with a 200-4r and a 29" tire. It didn't paste verywell from Excel it is is based on the overdrive of .67:1 so all figures in the table assume the Torque converter to be locked up in 4th gear. I run a Goodyear Wrangler P235/75r15 whuch is about the same height as the original "H" on the SPID. Tach GR = gear ratio (3.73 x .67 = 2.499) TFT = Total Feet Travelled at Tach RPM * FT MPH 1000 2.50 3,025.96 34.4 2000 2.50 6,051.91 68.8 2500 2.50 7,564.89 86.0 2800 2.50 8,472.68 96.3 3000 2.50 9,077.87 103.2 3200 2.50 9,683.06 110.0

09-12-2012, 03:50 PM	#20
BlackedOut67shorty Registered User Join Date: Aug 2012 Location: error 404 location not found Posts: 816	Re: Highway Speeds 67 c10 swb 350 turbo 350 3.73 P235/75 R.15 70-75 mph @ 3000-3300 rpm __________________ 1995 s10 blazer 4.3 1967 c10 350/350 fleet short 1993 s10 blazer 4.3l 4l60 RIP 6/20/14 2000 mercury sable Thats a how I roll

09-12-2012, 08:33 PM	#21
502ms Registered User Join Date: Aug 2011 Location: Atlanta, GA Posts: 1,523	Re: Highway Speeds Subscribed. I will capture this and get back to you. I want to be dead on. I am pondering my next move with my drivetrain (whether it be a 4L80E or a built T56) and something nice in front of it...5.3/6.0 or just a 383 stroker until I get my beloved 572 __________________ Best Regards, Leon M. Instagram: @TheDirtyDianah Bagged \| 6.0L LS \| T-56 (6-Speed Manual) \| Turbo Burnout/Rolling Video: Chevy C10 Stepside 6.0L LSx & 6-Speed Manual

09-12-2012, 08:48 PM	#22
big_al_71 Registered User Join Date: Jun 2008 Location: South Florida Posts: 11,375	Re: Highway Speeds Truck type 71 swb - Engine small block 400 -Tranny th350 -Rear end gears 373 auburn posi -Height of rear tires 295.40.20 and the RPM's when going 70-75 MPH.. 2900rpm-3000rpm __________________ Get your facts first, and then you can distort them as much as you please!!!!!. Sylvester's build thread >>>http://67-72chevytrucks.com/vboard/s...ht=big+rebuild



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09-13-2012, 01:43 AM	#23
cubber Registered User Join Date: Mar 2012 Location: Leanna, TN Posts: 2,061	Re: Highway Speeds 69 swb stepper 250 I6 TH350 3.42 or 3.08 gear (maybe somebody can tell from this info) 70ish (speedo a little off from gear change) @ 25-2700 rpm 255/70r15 tires 15+ mpg __________________ =MATTHEW 69 Stepper...Stroked & Bagged GONE BUT NOT FORGOTTEN 2003 Chevrolet Z71 Ext. Cab 1995 Cavalier gas saver!

09-13-2012, 09:42 AM	#25
LEEVON Registered User Join Date: Jul 2006 Location: Ozark, MO Posts: 4,887	Re: Highway Speeds 71 swb 355 heads/cam 700R4 w/ 2200rpm converter 3.73 255/60/15 (28"-ish) 22-2300 RPM at 70mph locked. 2500-2600 unlocked. This is pretty much the ideal gearing in my opinion, although I prefer to cruise at 65mph. Every truck has an ideal cruising speed, mine is governed by road and wind noise, vibrations, etc. __________________ '20 Silverado Trail Boss ~ '17 Tahoe ~ '79 K15 Sierra Grande ~ '76 Blazer 2wd ~ '71 Cheyenne swb ~ '55 Pontiac Safari ~'50 3100 bagged ~ '80 Wife ~ Late model kids

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