Top end speed on daytona or superbird?

[troy.70R/T]

I was just wondering if anyone knows the top end speed of a (stock) Daytona or a Superbird. I mean like the salt flats or an Arizona or Nevada black top.  Id like to know gear ratios engine size, and transmission specs if anyone has them? I had my 68 383 with 3:23 gears  and auto doing what i thought was about 160 MPH (I remember it passing the 150 MPH mark on the speedo, but it has been years since then if I can remember right). But I had my 70 ( the one in my profile pic) doing only about 140 as it reached the red line (5500). with 3:55 gears and a 4-speed. just wondering the top end you all have gotten out of your BIRDS.

[cdr]

the info on your 70 model @ 5500 rpm with a 27" tire would be 124.mph
the other car top speed would be about the same,  speedometers must not have been correct.

[richRTSE]

Here you go, you can play around with numbers yourself... 

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

[odcics2]

 

[ksquared]

Here you go, you can play around with numbers yourself... 

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

From the calculator, to me the only real way to increase top speed is to get a numerically lower gear ratio.  I never understood why some of these cars came with 4.11 gearing, when they were really made for top speed.  I'm not really sure how numerically low of a gear ratio (I would think 2.xx) there can be and still have the car able to start moving forward.  I don't understand either why there isn't an overdrive gear in the transmission too.

[Arnie Cunningham]

As everyone here knows it is the differential gearing that was the limiting factor on these cars not the power.  One thing not mentioned yet is the ratios available in the dana 60.  The lowest I've heard of was like 3.30s or something in a ups truck.  Anyone else heard what the limits are for the dana 60 case?

[ws23rt]

These cars were sold to folks that drove on roads and freeways where they live and were geared for that. If a car were to be sold with top speed as the selling point the customer would be right back with regrets.

The race cars that sold the wing cars were not regular traffic friendly.

The charts that others have shown should answer the question.

[odcics2]

The race wings used an 8 3/4, 1.75 straight pinion shaft.
Ratios were from 2.76 to 6.13.  About 25 numbers between those two were available for any track length. 

Imagine a 6:13!   

[alfaitalia]

6.13 . Amazing they could change gear fast enough!

[aerolith]

I think the 6.13 gears were designed for MONSTER trucks with 60 inch tyres...

2.76 is the only way to go fast with an 8 3/4.(Then fit a gear vendors trans with 33 inch Pro-mod tyres and your good for 200+.)

What ride that would be...

A good 440/hemi with 26inch tyres, flat out at 5500rpm with 2.76 gears will make 150mph (with a tail wind).

To make the magic 200mph you will need...

2.76 gears, 29inch tyres and a motor that will pull/rev to 6400rpm's.
Easy as taking candy from a baby...

The 200mph Daytona oval-track record hemi must have been pulling 7000rpms with extra tall rear tyres fitted...
Trick stuff for 1970, without a doubt!!!

[odcics2]

Actually, 28.75" at the road...
198.xxx coming out of 2.
202.+  going into 3.
Only 150 rpm variation over an entire lap.

[68X426]

Can a custom ratio be built?  Lower than 2.76?  Isn't that what the racers do for Bonneville?

I know the original question is regarding stock, but can it be done?

[thehemikid]

I know this route is not in the "stock" factory parts options but the Passon 4 spd O/D has a .8 gearing in 4th, giving a 3.54 rear an equivalent of 2.83 and uses the stock trans housing's, and is stronger than a Hemi 4 spd.

If you can ever    get one of the Passon 855's,  it has a .7 gearing in 5th giving the 3.54 rear a 2.47 equivalent, and is also a bolt in, no cut deal.

Doesn't fit in a stock discussion very well, but looks pretty good in the calculator.

[odcics2]

Can a custom ratio be built?  Lower than 2.76?  Isn't that what the racers do for Bonneville?

I know the original question is regarding stock, but can it be done?

Yes. Just costs $$$$$$$ !!!

[odcics2]

The K&K hemi had to turn 7K to run 217 at Bonneville if it had a production ratio 2.76 gear in the back.
That's easily a few hundred RPM over where they used to just blow up.  Lots of piston/rod mass. Lots of valve float.
Remember - 1970 technology.

So, maybe a hand cut set of rear gears???  

A 2.65 will get that speed at a livable RPM.

[HPP]

In a racing environment, custom gears or quick change rears would be the norm. They absolutely were not limited to stock ratios.

[odcics2]

In a racing environment, custom gears or quick change rears would be the norm. They absolutely were not limited to stock ratios.

A Nascar stock car, back then, was limited to an 8 3/4 axle, no quick change allowed, per the rule book.
Any gear ratio used had to be production, meaning a factory part number on it.
All the ratios from 2.76 to 6:13 have production numbers on them. 

BUT, the Bonneville runs were under loose USAC sanctioning so the Nascar rule book was tossed out the window.