Welcome to the THE H.A.M.B. forums.

You are currently viewing our boards as a guest which gives you limited access to view most discussions and access our other features. By joining our free community you will have access to post topics, communicate privately with other members (PM), respond to polls, upload content and access many other special features. Registration is fast, simple and absolutely free so please, join our community today!

Go Back   THE H.A.M.B. > General Discussion > The Hokey Ass Message Board

Reply
 
Thread Tools Display Modes
Old 02-25-2010, 03:33 PM   #1
lotus
Senior Member
 
lotus's Avatar
 
Join Date: Sep 2002
Location: Taft, CA
Posts: 1,127
Default SBC what RPM range is ok for highway use?

What is an acceptable RPM range for a SBC at highway speed?

I have a 383 SBC with 700R4 tranny, 4.56 posi, and 28" tall tires...here is what I am looking at with that setup.

RPM:2500
Tire Diameter: 28"
Axle Ratio 4.56
Transmission Ratio: .7
MPH = 65.27

This is going to be in a 55 chev truck.

2500RPM seems like it would not shorten the life of t he motor and be doable on 2hour trips to the coast.

just realized to...when it drops out of OD 65mph becomes 3700 RPM

what do you think?


__________________
Lotus
65 Falcon
offline   Reply With Quote
Old 02-25-2010, 03:36 PM   #2
Frank K
Grenade Inspector
 
Frank K's Avatar
 
Join Date: Dec 2005
Location: Southern Ontario Canada
Posts: 187
Default Re: SBC what RPM range is ok for highway use?

Safe for cross country...Frank Kunkel
offline   Reply With Quote
Old 02-25-2010, 03:37 PM   #3
Desoto291Hemi
Grenade Inspector
 
Desoto291Hemi's Avatar
 
Join Date: Apr 2009
Location: Carthage , Tennessee
Posts: 353
Thumbs up Re: SBC what RPM range is ok for highway use?

Sounds good,,it should work fine.
In overdrive,,I would prefer a little bit less rpm at highway speeds,,,around 2200,,but it won't hurt a thing.
The 4.56 gear should really haul when it is needed.

Tommy
offline   Reply With Quote
Sponsored Links (Register now to hide all advertisements)
Old 02-25-2010, 03:37 PM   #4
GREASEMONKEY72
Member
 
GREASEMONKEY72's Avatar
 
Join Date: Nov 2007
Location: bakersfield, ca
Posts: 498
Default Re: SBC what RPM range is ok for highway use?

2500 aint bad at all
__________________
-steven
Alte Seele S.S.

PITBULL IS NOT A CRIME
offline   Reply With Quote
Old 02-25-2010, 03:40 PM   #5
lotus
Senior Member
 
lotus's Avatar
 
Join Date: Sep 2002
Location: Taft, CA
Posts: 1,127
Default Re: SBC what RPM range is ok for highway use?

yeah i figure it will be a blast to drive around town...should be a stump puller and still be drivable on the highway. The motor should make most of its torque/hp under 5k rpm.

i imagine i will be spending time working on getting it to hook up vs hop really bad.
__________________
Lotus
65 Falcon
offline   Reply With Quote
Old 02-25-2010, 03:42 PM   #6
big creep
Old School HAMBer
 
big creep's Avatar
 
Join Date: Feb 2008
Location: Burbank, CA
Posts: 2,951
Default Re: SBC what RPM range is ok for highway use?

yea that sounds about right. my work truck runs a little closer to 2200 rpms and thats with 4.11 in the back.
__________________
Build a bridge and GET OVER IT!
offline   Reply With Quote
Old 02-25-2010, 03:47 PM   #7
3wLarry
Old School HAMBer
 
3wLarry's Avatar
 
Join Date: Mar 2005
Location: Owasso, Ok
Posts: 10,300
Default Re: SBC what RPM range is ok for highway use?

I got a 3:55 rear gear in my '56 chevy truck and a crate motor 350/350 trans...it does 70 mph all day long at 2800 rpm's. Doesn't get great gas mileage, but who cares?
offline   Reply With Quote
Old 02-25-2010, 03:54 PM   #8
Diehard32
Grenade Inspector
 
Diehard32's Avatar
 
Join Date: Nov 2007
Location: Pasadena, Texas
Posts: 233
Default Re: SBC what RPM range is ok for highway use?

Depends on how fast you want to get where your going.... Just kiddin'

With that stump puller gear, your mileage will suffer somewhat, but it all depends on how far you plan to travel.
Longer trips = mo $$$......But its just money.
__________________
No problem can stand the assault of sustained thinking. VOLTAIRE
offline   Reply With Quote
Old 02-25-2010, 03:55 PM   #9
lotus
Senior Member
 
lotus's Avatar
 
Join Date: Sep 2002
Location: Taft, CA
Posts: 1,127
Default Re: SBC what RPM range is ok for highway use?

yeah i am not too concerned with gas mileage...I also have a Ford 8.8 with 3.73 gears that I will put in if I decide the 10bolt 4.56 is too much.

avg trips will be 2 hour trips to the coast/LA. longest trip it would see could be Vegas from Bako or to the Bay area...
__________________
Lotus
65 Falcon
offline   Reply With Quote
Old 02-25-2010, 04:08 PM   #10
hotroddon
Old School HAMBer
 
hotroddon's Avatar
 
Join Date: Sep 2007
Location: Orange, So Cal
Posts: 11,474
Default Re: SBC what RPM range is ok for highway use?

Back in the days before Overdrive transmissions, we used to figure a 40% rule for highway driving a "real" Hot Rod. In other words 2400 at 60mph 2800 at 70 etc. Still gave strong acceleration and was livable on the road.

I used to drive a 331" small block from So Cal to Northern Cal and Vegas regularly at 2800-3000 rpm, and other than using a bit of gas, no big deal. Put a ton of miles on it
__________________
As I hurtled through space, one thought kept crossing my mind
every part of this rocket was supplied by the lowest bidder. ~ John Glenn

offline   Reply With Quote
Old 02-25-2010, 04:27 PM   #11
Lalos53Ford
Member
 
Lalos53Ford's Avatar
 
Join Date: Jul 2007
Location: Richmond, Indiana
Posts: 693
Default Re: SBC what RPM range is ok for highway use?

I run around 2600 rpm at 70 mph on the highway and seems to be just fine. She has plenty left when I gas on her. 355/th350 does nice.
__________________
1 Peter 4:10
______________________________________

Having trouble figuring out "how-to"?
Join the Little Pages Tech Archive
online   Reply With Quote
Old 02-25-2010, 04:36 PM   #12
hotrod40coupe
Alliance Member
 
hotrod40coupe's Avatar
 
Join Date: Apr 2007
Location: HENDERSON, NV
Posts: 2,541
Default Re: SBC what RPM range is ok for highway use?

Like everyone has said, shouldn't be a problem as long as you are willing to sacrafice mileage.
offline   Reply With Quote
Old 02-25-2010, 04:41 PM   #13
J&JHotrods
Member
 
J&JHotrods's Avatar
 
Join Date: Oct 2008
Location: Olathe, Kansas
Posts: 518
Default Re: SBC what RPM range is ok for highway use?

Quote:
Originally Posted by lotus View Post

.....just realized to...when it drops out of OD 65mph becomes 3700 RPM

what do you think?

Sounds like the passing gear will be in the meat of the power range. Not the best for MPG, but ought to be fun!
__________________
"find it or grind it"
Jay
offline   Reply With Quote
Old 02-25-2010, 04:56 PM   #14
Truckedup
Old School HAMBer
 
Truckedup's Avatar
 
Join Date: Jul 2006
Location: Western NY hillbilly
Posts: 3,225
Default Re: SBC what RPM range is ok for highway use?

A lot of guys,me included, used to run 4-1/2's and gave no thought to buzzing down the hiway at 3500 rpm for hours.Not only SBC's but BBC's and B block Mopars.
offline   Reply With Quote
Old 02-25-2010, 05:03 PM   #15
53vicky
Member
 
53vicky's Avatar
 
Join Date: May 2009
Location: Placerville, California/ Reno, Nevada
Posts: 925
Default Re: SBC what RPM range is ok for highway use?

I drove my 283 with a 2 speed powergluide from nor cal to so cal all the way at probably 3500 rpms. Didnt seem to hurt her at all.
It actually was good my my tranny to run it for awhile like that.
offline   Reply With Quote
Old 02-25-2010, 05:13 PM   #16
ChevyRat
Member
 
ChevyRat's Avatar
 
Join Date: Oct 2007
Location: Marion, Texas
Posts: 576
Default Re: SBC what RPM range is ok for highway use?

Does not sound to bad at all
__________________
Rebels Race Club
San Antonio, Texas
Founded 1953

offline   Reply With Quote
Old 02-25-2010, 05:19 PM   #17
cleatus
Senior Member
 
cleatus's Avatar
 
Join Date: Mar 2002
Location: Sacramento
Posts: 2,272
Default Re: SBC what RPM range is ok for highway use?

I think the 4.56 gears will be way overkill, unless you are running some really wide rubber.
I also have a 383/700R4 and my gears are only 3.25.
Granted, my 3.25 are actually overkill in the opposite direction - 3.50 would be more ideal, but even with the 3.25 gears I can easily spin both rears off the line, so how much more bottom end grunt is really needed?
And it is really nice to hit the Interstate at 1900 rpm.
4.11 would still be more than good.
offline   Reply With Quote
Old 02-25-2010, 05:25 PM   #18
mustang9093
Newbie
 
mustang9093's Avatar
 
Join Date: Dec 2008
Location: Indiana
Posts: 87
Default Re: SBC what RPM range is ok for highway use?

Good combo with a killer first gear. Make shure the camshaft is happy at highway rpm. Drag race cams and overdrives dont get along.
offline   Reply With Quote
Old 02-25-2010, 06:20 PM   #19
Russco
Old School HAMBer
 
Russco's Avatar
 
Join Date: Nov 2005
Location: Central IL
Posts: 3,121
Default Re: SBC what RPM range is ok for highway use?

Thats a final drive ratio of 3.19 which is very close to the 3.08 millions of SBC came from the factory with it will do more than that easily alll day long
__________________
Life is hard. After all, it kills you.
offline   Reply With Quote
Old 02-25-2010, 07:12 PM   #20
lotus
Senior Member
 
lotus's Avatar
 
Join Date: Sep 2002
Location: Taft, CA
Posts: 1,127
Default Re: SBC what RPM range is ok for highway use?

the 28" tall wheels i have right now will not hook up at all... 235x70x15

I am still debating on running steel wheels with cheater slicks in the back or running my rocket wheels with some meaty tires in the back.

I ended up with the 4.56 10bolt because it was a hell of a deal and has after market axles...ideally i would like something a little less dramatic but i am going to run it and see how I like it before I make any changes.
__________________
Lotus
65 Falcon
offline   Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is On

Forum Jump

Sponsored Links (Register now to hide all advertisements)


All times are GMT -5. The time now is 06:29 PM.