1963 Buick Riviera engine rpm/mph

[robcroft6363]

Hi - Looking for anyone who has a original tach, or aftermarket, in their '63 Riv. I feel it revs quite high, but its hard to determine especially when the car is only used in the summer. I have owned for 16 years but never noticed the "high" rpm/mph until this year. (Am I too used to my new modern car?)  I temporarily hooked up a tach I purchased, switched it to 8 cyl, ran the wires from under hood through side vent window to the dash. I got the foll. numbers:

40 mph- 1500rpm

50-          2150

60-          2600

70-          3000 

With Dynaflow trans its is impossible to know what "gear" youre in as it correctly does not "shift".  Car has standard 710x15 tires, no mods. Trusting the tach I bought is more or less accurate. Would be great to hear from other owners with their RPM/MPH, so I can relax and enjoy the car. 

[robcroft6363]

I should also mention I used my iPhone app xSpeed to record MPH, not the speedo. 

[tenugent]

Depends on your rearend gears,my rearend is a posi 323 at 65 its about 2500.

[RivNut]

You're lucky. When i first got my 63, it had a 3.91 rear gear. Drove it as my daily driver in rush hour both ways. Either 75 or standing still. 

[Wayne R]

Hello , i would think  with those  710 tires on , its about right, perhaps a fraction high,

with 710  tires thats about the same as    205  in modern size.---probably about 27 inches diameter.

Go to this forum   below about a week ago i  listed a chart on tires , it may not have your size on there,

but its very helpful-----especially the diameter of tires,--- its   heading  ---wwtire options by  Mr AG.

And as Tenugent says  rear end   the same.

[NTX5467]

After searching the road tests archived at the Automotive History Preservation Society's website, I found some information which might apply, or be used as "similar" data.

 

1955 Buick Century w/improved DynaFlow, 3.4 axle ratio, 7.60-15 tires (just a bit taller than 7.10s).  In their chassis dyno power tests, 3100rpm was 76mph, about 25mph/1000rpm.  Under load on the chassis dyno, "going up a hill at WOT", they noted.

 

1966 Riviera GS 3.42 axle ratio, 8.45x15 tires (repl 7.60, I believe) was 23.7mph/1000rpm.  

 

So, with the 3.4-type rear axle ratio of the Riv GS, about 24mph/1000rpm.  In a 1965 LeSabre road test 3.08 gear ratio and THM400, it was more like 26.3mph/1000rpm.

 

Resulting general approximations?  24mph/1000 with 3.42, 26.3 mph/1000 with 3.08, and probably . . . 25mph/1000 with 3.23s and 20mphj/1000 with the optional 3.91s.

 

Now, "sounding revved-out" can be just that, SOUNDS, which are not specifically related to rpm, but the "happiness" of the engine doing what it's doing.  By comparison, many modern GM cars and pickups are turning 1700rpm at 70mph in top gear, with much better sound insulation and quiet exhaust systems.

 

Hope this might help,

NTX5467

[60FlatTop]

That's what feels good about driving my old V8 cars. The RPM is up there and the car responds to just a nudge on the gas pedal.

 

When I was commuting to work I lived 7 miles from the last expressway exit. Many times I would drop my modern vehicle out of overdrive just to get that good feeling for those few miles.

[NTX5467]

Some additional tire size information I found in an AMA Specification Book/Survey for a 1960s Buick.

 

As to tire size: 

7.10x15 tires have a "Revs/Mile @ 30mph" spec of 750 revs/mile    Which equates to a modern P215/75R-15 or P227/70R-15 size, previously known at "G78x15" and "G70x15".  Most of the modern tires are more like 756 revs/mile, by observation.

7.60x15 tires have a "Revs/Mile @ 30mph" spec of 735 revs/mile   Which would equate to a modern P225/75R-15 size, previously known as "H78x15"

8.00x15 tires have a "Revs/Mile @ 30mph" spec of 723 revs/mile   Which would be very close to a modern P235/75R=15 or prior L78x15 tire size

 

The "Revolutions/Mile" spec is important as it relates to the number of revolutions the speedometer cable (and the internal speed cup on the back of the speedometer mechanism) makes to drive the odometer unit and outer speed cup (which moves the speedometer needle).

 

Enjoy!

NTX5467