Got a techical question about gear ratio and power. - The 1947 - Present Chevrolet & GMC Truck Message Board Network

In The Ten Ring · 11-12-2024, 02:54 PM

Hey guys,

First off, it's been 2017 since I've been on here, glad this site is still around!

Just been busy with life. Married now and started a new business which takes up all my free time. Still have my 1972, nothing has changed since the last post I made about it.

Anyway, here is the question.

Looking to buy a dump truck. Found a nice mid 1980's model, 427 V8, 3 speed manual in floor, 3:55 gears.

What can I expect from that? Good power? Can I pull WV hills easily? What top speed?

I like to do about 55 mph on the interstate, no matter what I am driving.

Thanks!

***EDIT***

Don't worry about it....someone snatched it up. I was hoping to go look and perhaps buy it on Friday. :-(

weq92f · 11-12-2024, 06:18 PM

.

Welcome back. If you knew the model of tranny, you'd ~maybe~ be able to determine the gear ratios and use that with an Online calculator to figure out final drive ratios to get an idea of what it'll do.

My guess is first and second are very low with 3rd being something near 1 but higher. It's likely a dog off the line and might do 50-60 MPH unloaded at full rip. If you load it up it would do close to that still but a lot slower to build speed.

-Kevin

**Steeveedee** · 11-12-2024, 06:28 PM

A 427 has a lot of grunt. With a 3.56 axle and 16.5" wheel, and using the 9.50-16.5 Firestone Transforce tires (31 inch OD), I'm running about 2200 at 55 MPH. What tonnage do you expect to haul?

In The Ten Ring · 11-12-2024, 10:49 PM

Thanks, nice to be back.

I hope to mount a 460 pound leaf vacuum to the frame and fill that bed with chopped up leaves a max of three months a year. All other months the vac will be off and stored in my garage on a wheeled cart.

Spring, summer, and fall I may (if I can find employment doing such) haul perhaps 2000 pounds of gravel for people.

I don't have an end-loader but may be able to get a large-enough tractor with a grapple to aid in brush-clearance jobs---which I actually do a lot of.

I'd much rather have a 1971 or 1972 C30 dump truck but haven't seen one with a long-enough bed for me.

**kwmech** · 11-13-2024, 11:58 AM

What is this Dump truck? C40, C50? 2 speed rear end? overdrive? tire size? 20'' or 22'' rims pics

In The Ten Ring · 11-13-2024, 04:42 PM

Oh I'm sorry.....didn't put all the info down.

No idea on wheel or tire size but it's a C 30.

11-12-2024, 02:54 PM	#1
In The Ten Ring Registered User Join Date: Jun 2013 Location: West Virginia Posts: 6,427	Got a techical question about gear ratio and power. Hey guys, First off, it's been 2017 since I've been on here, glad this site is still around! Just been busy with life. Married now and started a new business which takes up all my free time. Still have my 1972, nothing has changed since the last post I made about it. Anyway, here is the question. Looking to buy a dump truck. Found a nice mid 1980's model, 427 V8, 3 speed manual in floor, 3:55 gears. What can I expect from that? Good power? Can I pull WV hills easily? What top speed? I like to do about 55 mph on the interstate, no matter what I am driving. Thanks! *EDIT* Don't worry about it....someone snatched it up. I was hoping to go look and perhaps buy it on Friday. :-( Last edited by In The Ten Ring; 11-13-2024 at 11:42 PM.

11-12-2024, 06:18 PM	#2
weq92f Registered User Join Date: Oct 2016 Location: Dallas Texas Posts: 3,162	Re: Got a techical question about gear ratio and power. . Welcome back. If you knew the model of tranny, you'd ~maybe~ be able to determine the gear ratios and use that with an Online calculator to figure out final drive ratios to get an idea of what it'll do. My guess is first and second are very low with 3rd being something near 1 but higher. It's likely a dog off the line and might do 50-60 MPH unloaded at full rip. If you load it up it would do close to that still but a lot slower to build speed. -Kevin __________________ 67 C10 fleet fuel injected '70 402, 700r4, 3.73 posi 07 335 sport turbo 6sp 94 Trans Am GT LT1 6sp posi -- sold after 22yrs 99 540 sport V8 6sp -- sold 73 240z L24 4sp -- given to friend 68 C10 step 350/350 3.73 open -- sold

11-12-2024, 06:28 PM	#3
Steeveedee Who Changed This? Join Date: Jan 2013 Location: Simi Valley, CA Posts: 10,613	Re: Got a techical question about gear ratio and power. A 427 has a lot of grunt. With a 3.56 axle and 16.5" wheel, and using the 9.50-16.5 Firestone Transforce tires (31 inch OD), I'm running about 2200 at 55 MPH. What tonnage do you expect to haul? __________________ ~Steven '70 Chevy 3/4T Longhorn CST 402/400/3.56 Custom Camper Simi Valley, CA

11-12-2024, 10:49 PM	#4
In The Ten Ring Registered User Join Date: Jun 2013 Location: West Virginia Posts: 6,427	Re: Got a techical question about gear ratio and power. Thanks, nice to be back. I hope to mount a 460 pound leaf vacuum to the frame and fill that bed with chopped up leaves a max of three months a year. All other months the vac will be off and stored in my garage on a wheeled cart. Spring, summer, and fall I may (if I can find employment doing such) haul perhaps 2000 pounds of gravel for people. I don't have an end-loader but may be able to get a large-enough tractor with a grapple to aid in brush-clearance jobs---which I actually do a lot of. I'd much rather have a 1971 or 1972 C30 dump truck but haven't seen one with a long-enough bed for me.

11-13-2024, 11:58 AM	#5
kwmech Senior Member Join Date: Mar 2003 Location: Colfax-California Posts: 8,602	Re: Got a techical question about gear ratio and power. What is this Dump truck? C40, C50? 2 speed rear end? overdrive? tire size? 20'' or 22'' rims pics

11-13-2024, 04:42 PM	#6
In The Ten Ring Registered User Join Date: Jun 2013 Location: West Virginia Posts: 6,427	Re: Got a techical question about gear ratio and power. Oh I'm sorry.....didn't put all the info down. No idea on wheel or tire size but it's a C 30.



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