3K RPM's Get's Me 70 MPH What Do U Get?
 

3000 RPM's Get's Me 70 MPH What Do You Get?
TH400 350. Do I need the tire size to find out what gears are in the rear end?

I sure would like to be in the 1700 range at 70 MPH. Maybe a 700r Tranny?


Lets here it


Eric

My 402 turn at about 3200rpm on the freeway at the legal posted 75 speed limit.According to the code on my axel i have 3.08 gears,my tirs are 31x10.50 15's.seems hi to me,maybe the factory tach is off,i hope.I wouldnt care if it was a 283 or something a smallblock doesnt mind the rpms much,but big blocks dont like hi-rpm-a little hard on them after a while.

You need the tire size to figure this out. Take a look here when you have the information. You should be able to plug in the numbers on the rpm calculator. http://www.ring-pinion.com/

I turn 2400 at 75

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• 71 Chevy CST Long Fleet 350/350/3.07 leaf rear.
• Email: 67-72truckparts@nanosecond.com

Next truck i build i have a 468 going into a 67 SWB project and id like to put in a 700R4,love to loaf along the freeway at 125 mph at 2000 rpm and get 20mpg,awaking from my dream,now.hey i can wish.I think a fuel injected,468 ci motor, over 500hp and 20 mpg would be sweet,7-10 mpg sucks even in a cruiser when you got $10 in your pocket and you still need to buy some beer,and tanks on E.its called 2 gallons of gas,and a bunch of cheapy malt liqour 40oz ers.or a nasty $7 bottom of the shelf 5th of whiskey.

3000 rpms @ 60 mph.....4.10 coggs on a 28" tire. FUN!.....69 longhorn.

lol desert rat

I get 2500 at 50,about 3000 around 60 and right at 3500 to 3750 at 70.I am running a
350/350 with 275/60-15's on the rear.That 700r sure looks good sitting in the garage, Can' wait till it is between the frame rails!

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'72 longbed,350\350,4\6 drop,p.s,p.b,tach.
http://hometown.aol.com/rp2bp/myhomepage/auto.html

3000 rpm's gets me roughly 75 mph. 3.07 rear gears, and 255x60-15 tires. I hope to upgrade to a 700R4, and i may keep the high gears. Then i will be praticly idling at 75 http://67-72chevytrucks.com/board/ubbhtml/smile.gif. I heard somewhere that the 700r4 won't cruise at high speeds in OD because the tranny will kick down at 2/3 throttle. Is this true, and if so is there a way to get it to stay in OD at full throttle? I dont wanna drive too fast, but a run up to 130+ sure would be fun http://67-72chevytrucks.com/board/ubbhtml/smile.gif.

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Lucas

"Another proud owner of one of the coolest trucks ever built"

drop_shift@hotmail.com

My Daily-Driver: '72 Chevy LWB Custom/10. Rebuilt 350, 300 HP thanks to a few go-fast goodies. Ochre with a white top. Future plans include TBI fuel injection, a 700R4 tranny, and possibly some 3.73 rear gears.

Jeggs carries the part you need for that. Still won't run full throttle, but it'll cruise at 3/4 throttle in 4th

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'69 G.M.C. 350/350. Trying to clean up the left over damage from the Dope-Smokin-Old-Man
I've been dubbed the Longhorn Freak/Fanatic/Expert, I just hope I can live up to it.
FINALLY got the HORNIAC...a '70 one ton Longhorn with a Pontiac 350/350 and lots of 'personality'. Check out The Longhorn Webite.
If you need a pic posted, E-mail me at longhornmail@yahoo.com
Andy, in Columbus Ohio

2000 rpm at 75. 3.73 gear with a t5 tranny.

Well, after a bit of cypherin I have the ratio at 3.82. Sound about right?

I cant tell if the tire is 30 or 30.5


Eric

Hey Desert Rat sounds like your factory tach is the problem!!! I'll take that defective piece of equipment off your hands. I'll even pat postage. lol.

3,000rpm gives me 80+MPH. 308rear--96 1/2 ton 5speed, 235x75R15 rubber. 20+mpg on the flats. If towing, downshift to 4th on bigger hills. GOT to love that 5 speed!!
By the way, hear tell that our factory Tachs do not read true if using HEI ignition (heard/read on ColoradoK5). The tachs read higher then reality!?

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72 Cheyenne, 350, 5spd, LWB, Super trim.
71 GMC JIMMY 4X4 --needs stuff-!

Our factory tachs can be recalibrated. I calibrated my factory 6 cyl tach to a aftermarket tach for my V8 with HEI. Works perfect.
Sounds like you read some bad info.

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• 71 Chevy CST Long Fleet 350/350/3.07 leaf rear.
• Email: 67-72truckparts@nanosecond.com

[This message has been edited by 71Chev (edited April 06, 2002).]

60mph @ 3000rpm w/stock 3spd manual & 3.73's w/275/60/15's. 12-13mpg on the open road w/a friggin' 6 banger/1 barrel sucks. From Dallas to Houston or Tulsa, OK: 1 tank gas/1 qt oil there, same coming back. Sounds like a candidate for o.d. huh?

2700 rpm's=125db's yeah louder than a jet. Hookers, Supertaps, and 35x15.50 super swampers. And we'd be rollin! http://67-72chevytrucks.com/board/ubbhtml/smile.gif

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67 stepside 4x4 Owensville MO mudder67@hotmail.com

I just did the 700r change over thanks to Bowtie overdrives & I went from a 350ci/T400 w/ 3.73 rear that got 3000 rpm=70 on 31x15 tires to now I have the same engine/rear/tires but only 2000rpm @ 70...man I can't tell you how much I love the new trans. The Bowtie folks where way cool (www.700r4.com ??? or www.bowtieoverdrives.com) I got everything except the crossmember (next time I would order that also) and no core charge. All went in smooth & after the pressure test & the over the phone walk through I now am shifting harder than before (and the T400 is a B&M factory built unit...anyone want it???) and the mileage is way better.
Anyway I love the 700r and would never go back.
1 Leg Lance

1 leg. I cant get to the bowtie site is it correct? What do you want for the 400?

here's the site --
http://www.bowtieoverdrives.com

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72 Sierra Grande - "Maych"
sierraG on some boards

If a man speaks in the middle of a forest and there is no woman around to hear him, is he still wrong?

Forget about "do it right the first time". Do it wrong the first time to learn how, then do it right the second time.

Maych Home Page

I run about 2300 at 70mph with a 350/th350, 3:08 Posi and 35" tires. Would like to run 4:10's some day.

I get 65 MPH at 3000 RPMs, with 325/60R15 BFGs(31-12.5 equivalent) and 4.10 gears.

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1970 GMC K25 Custom
Chesapeake, VA
My 70 GMCor Webshots http://community.webshots.com/user/70gmc

60 mph=1800 rpm for me

Re: 3K RPM's Get's Me 70 MPH What Do U Get?
 

Reviving an old thread here...

These RPMs @ MPH being reported are much lower than I expected.

72' Blazer: 3,500 RPM at 60 MPH with a 350/TH350 and 33" tires. I don't know what the gear ratio is but if I had guess, it's 4:56 or 4:88.

BTW- for folks trying to what gear ratio to choose if changing tire size, I found this informative clip on youtube.

https://www.youtube.com/watch?v=oDVpyhKEbaw

Re: 3K RPM's Get's Me 70 MPH What Do U Get?
 

Punching numbers in here says 5.72 gear.

Could be tach is wrong or excessive slippage in convertor.

http://www.advanced-ev.com/Calculators/TireSize/