Okay I am a GM Guy My buddy is a Dodge guy I am in a little dipute with him about how the SUPER BIRD hit 210MPH's.He said that the car was a Hemi car with something like 4.11 gears and traveled 210MPH's.I don't know what the car had for a Tranny but I said"I wonder what kind of RPM's he was turning with that setup" so we began to dipute the different gear ratios possibble. I say the car had Numerically lower gears to have more top end, he says the hemi was the big dog and could make the car go that fast. WOULD A TECHNICAL ADVISER PLEASE HELP ON THIS MATTER?POPULAR HOT RODDING RULES
With a 28 inch tall tire a 270 rear gear the engine would turn 6836 r.p.m. to go 210 mph. With 4.11 gears the engine would turn 10406 r.p.m. to do the same 210 m.p.h. I think this speaks for itself!!This was figured with a 1:1 four spd trans. If it had a 5 spd over drive (.68) 5th gear with 4.11 the r.p.m. would be 8325.
As a GM fan and a Mopar fan, I have to say, this sounds like BS. Not with 4.11 gears anyway, that just doesn't make sense. The 1969 Dodge Daytona hit 199mph on the circle track in Daytona, with the the 426 Hemi, and a four speed. Back in the day they also took that car out to the Bonneville Salt Flats, and hit a little over 200mph (can't remember the exact number). Even the 'public' versions of these cars were pure race cars, and would overheat if consistantly run under 55mph.The 1970 Plymouth Superbird was not as streamlined as the Daytona, and did not have the top end speed that it's predecessor had, although still being able to run around 190+. The Superbird was also better fit for the streets, in that it could take in a little more air for cooling than the Daytona could.Either way, unless the car was further modified from it's NASCAR roots, 210mph out of a Superbird in "stock" form is unheard of. Maybe he was referring to the Bonneville runs with the Daytona, not the Superbird?
Hemis w/ the Scat Pack would have 4.10, but 3.54 was optional. Still, Nascar was using Super T10 four speeds, no overdrive there. Whether a stocker had the Torqueflite or the A-833 New Process, both had 1:1 final ratios, and neither trans were lightweights--that's a lot to spin past 6,000RPM. The funny thing w/ superbirds was, they got vinyl roofs to cover up the fast bodywork done to flush the rear window (daytonas enjoyed the benefit of the Charger 500 that preceded it, already w/ flush glass). Anyway, the dimpled grain of vinyl tops did what dimples in a golf ball are designed to do...help air flow over the surface.Hemi's needed those 4.10's, b/c they really were more of a hi RPM engine, which is part of why 440's would eat 'em for lunch...on the starting line. The Hemi, when tuned, would catch up at the end of the 1320. Out of tune, not so much. The 200mph w/ 4.10 gears is seriously a myth that existed BEFORE the Internet..I have magazines from 1979, and saw stuff like this listed in Guide to Musclecars magazine somewhere back in the 1980's.the thing is, Corvettes of that decade COULD hit 150mph, w/out the 425 (at least) power of the Hemi. but, they had aerodynamics far surpasing that of the 'Birds who sat higher in the air.
Just because you can't do it...doesn't mean its impossible
in 1970 mopar sent a daytona charger to bonneville salt flats to set production car records, it did. it was NOT a showroom dealer drive off by any means! it was highly modified as allowed in the production class rules. if memory serves me the driver was nascar champ bobby issac.