RPM question - The 1947 - Present Chevrolet & GMC Truck Message Board Network

Jemost 72 · 02-02-2003, 12:23 AM

I recently bought a 1972 Cheyenne 350/350. It has a rebuilt motor with around 27k on it. I've had 2 '70 chevy trucks in the past, so I thot I had a good feel on how they drive.
This new truck has a 'towing cam' installed with an edelbrock carb. No other mods. When driving, the tranny shifts rather quick and very smooth, can barely feel it change gears. When I get up to 50 mph, it feels like it's winding out. At 60mph, I felt like it had 4.11 gears.
I opened up the rear diff today to change the fluid and count teeth. It's a 3.07 rear end.
Can ne1 give me some insight about this. Could it be this cam or sumthin in the tranny. Previous owner said he never touched the tranny for service or repair.
Thanks for your time and the great info on this site!
JJ

Longhorn Man · 02-02-2003, 12:24 AM

Could it just be louder than your previouse trucks?
Welcome to the board.

Jemost 72 · 02-02-2003, 12:34 AM

Thanx...It is louder than my last '70, it had turbo mufflers and this one has glass packs...but my 1st '70 also had glass packs..maybe its been too long since I've been around glass packs!
This is the first truck I've had that had an aftermarket cam and since the tranny hasnt been serviced in who knows how long, I was curious if either of these could be a factor.

Longhorn Man · 02-02-2003, 01:14 AM

I doubt you have a problem. The tranny would be more likely to slip on take off than cruising down the free way, and the cam would have no effect on the RPM at all.
Would you happen to have been in a daily driver for a while that is an overdrive? I find you get used to the current ride, and all previouse things kinda fade...my observations anyways.
If you have a 28-ish inch tall tire with 307 gears, you should be doing about this;

Or this if your having fun;

steves1967 · 02-02-2003, 02:19 AM

Man i wish that's all the rpm my truck spun!! I have 4.11's a 29" tire and i turn 3400 prm's at 70 mph. I can pass everythin gexcept a gas station!!

crazy longhorn · 02-02-2003, 10:37 AM

I have 4.10 Richmonds on a 28" tire......Ziiiing! It takes 3000 rpms @ 59 mph......4000 rpms will keep up with the big trucks on the hyway, & they run through Illinois @ 78-80 mph! crazyL

Longhorn Man · 02-03-2003, 12:23 AM

That second pic is the only time I like the cursed 3,07 peg leg one wheel wonder back there.

orange72350 · 02-03-2003, 01:17 AM

hey, longhorn, i got the same tach as u, and im wondering something. i cant tell in these pics, but do u have it mounted in the dash, or is it just mounted 2 the top of the column. if it is flushmounted, could u mabye tell me how u did it. im sick of having mine on the column. thanx

Longhorn Man · 02-03-2003, 01:24 AM

it is on the column there...but I have since mounted it in the dash.
All I really did was cut out the lens, and then hacked at the black metal piece untill the hole was bigger than the hole in the bezel. Then, I took the back piece of the inst cluster and beat it a few times with my hammer for clearance....then it slipped right in.

02-02-2003, 12:23 AM	#1
Jemost 72 Southern Bowties Join Date: Jan 2003 Location: Fort Worth, TX Posts: 240	RPM question I recently bought a 1972 Cheyenne 350/350. It has a rebuilt motor with around 27k on it. I've had 2 '70 chevy trucks in the past, so I thot I had a good feel on how they drive. This new truck has a 'towing cam' installed with an edelbrock carb. No other mods. When driving, the tranny shifts rather quick and very smooth, can barely feel it change gears. When I get up to 50 mph, it feels like it's winding out. At 60mph, I felt like it had 4.11 gears. I opened up the rear diff today to change the fluid and count teeth. It's a 3.07 rear end. Can ne1 give me some insight about this. Could it be this cam or sumthin in the tranny. Previous owner said he never touched the tranny for service or repair. Thanks for your time and the great info on this site! JJ __________________ 1972 Cheyenne 350/350

02-02-2003, 12:34 AM	#3
Jemost 72 Southern Bowties Join Date: Jan 2003 Location: Fort Worth, TX Posts: 240	Thanx...It is louder than my last '70, it had turbo mufflers and this one has glass packs...but my 1st '70 also had glass packs..maybe its been too long since I've been around glass packs! This is the first truck I've had that had an aftermarket cam and since the tranny hasnt been serviced in who knows how long, I was curious if either of these could be a factor. __________________ 1972 Cheyenne 350/350

02-02-2003, 10:37 AM	#6
crazy longhorn Fabricate till you "puke" Join Date: Jun 2002 Location: Ill Posts: 9,403	I have 4.10 Richmonds on a 28" tire......Ziiiing! It takes 3000 rpms @ 59 mph......4000 rpms will keep up with the big trucks on the hyway, & they run through Illinois @ 78-80 mph! crazyL __________________ 69 longhorn,4" chop,3/5 drop, 1/2 ton suspension/disc brakes,1 1/2" body drop,steel tilt clip, 5.3/Edelbrock rpm intake/600 carb, Hooker streetrod shorties,2 1/2" exhaust/ H pipe/50's Flows , 6 spd Richmond trans,12 bolt/ 3.40 gears....

02-03-2003, 01:17 AM	#8
orange72350 Registered User Join Date: Jan 2003 Location: Cold, Snowy High Level, Alberta Canada Eh Posts: 394	hey, longhorn, i got the same tach as u, and im wondering something. i cant tell in these pics, but do u have it mounted in the dash, or is it just mounted 2 the top of the column. if it is flushmounted, could u mabye tell me how u did it. im sick of having mine on the column. thanx __________________ 2003 yamaha raptor. Stock, but it still hauls!!!! 2000 skiddo mxz 700. Camoplast 1.5 inch track, jaws twin pipes, b+b can, custom built and weighted clutch, wiseco piston, high comp heads. its very fast. wow. 72 c-10 longbox. Bright Orange. Brand new 350, rv cam, performer intake, qjet, headers, 2 1/2 inch exhaust into hooker areo chamber mufflers. Body work coming soon. "dont let yer mind wander, its to little to go places by itself." "Forget the herse, cause i'll never die"-ACDC Back In Black "If It's To Loud, Yer Just Too Old" "I Love Anything Fast Enough To Do Something Stupid In" "Instant idiot, just add beer!!""

02-02-2003, 12:24 AM	#2
Longhorn Man its all about the +6 inches Join Date: Jan 2001 Location: Hilliard Ohio Posts: 2,693	Could it just be louder than your previouse trucks? Welcome to the board.

02-02-2003, 01:14 AM	#4
Longhorn Man its all about the +6 inches Join Date: Jan 2001 Location: Hilliard Ohio Posts: 2,693	I doubt you have a problem. The tranny would be more likely to slip on take off than cruising down the free way, and the cam would have no effect on the RPM at all. Would you happen to have been in a daily driver for a while that is an overdrive? I find you get used to the current ride, and all previouse things kinda fade...my observations anyways. If you have a 28-ish inch tall tire with 307 gears, you should be doing about this; Or this if your having fun;

02-02-2003, 02:19 AM	#5
steves1967 Registered User Join Date: Dec 2001 Location: Manteca, Ca USA Posts: 304	Man i wish that's all the rpm my truck spun!! I have 4.11's a 29" tire and i turn 3400 prm's at 70 mph. I can pass everythin gexcept a gas station!!

02-03-2003, 12:23 AM	#7
Longhorn Man its all about the +6 inches Join Date: Jan 2001 Location: Hilliard Ohio Posts: 2,693	That second pic is the only time I like the cursed 3,07 peg leg one wheel wonder back there.

02-03-2003, 01:24 AM	#9
Longhorn Man its all about the +6 inches Join Date: Jan 2001 Location: Hilliard Ohio Posts: 2,693	it is on the column there...but I have since mounted it in the dash. All I really did was cut out the lens, and then hacked at the black metal piece untill the hole was bigger than the hole in the bezel. Then, I took the back piece of the inst cluster and beat it a few times with my hammer for clearance....then it slipped right in.



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