royboy1952

Hoping that someone can answer this. Back in England in 1978 i bought a 1971 Mustang 351ci convertible with ram air ( hooked up ). The car would burn tyres for the whole block and back then i did it a lot as a 28 year old ! I got the car on a new stretch of motorway with 2 passengers and got it to 144 mph and it was still going but i caught up with traffic and had to slow down. The seller called it a Mach 1 but i do recall being told that the convertible was not actually classed as a Mach 1. I spoke to the local US car dealer in the city and told him about the car, and the speed ,and also told him the rpm at 144 mph. I asked him how i could make it go even faster and he told me to start with headers. When the headers arrived they did not fiton the manifold bolts. One had horizontal and the other vertical fitting bolts. He was surprised and told me that i must have the Windsor engine and not a Cleveland. He noted that i also only had a 2 barrel carb. I never really thought too much about it over the years until i moved to the USA in 1988 and found that Mach 1's usually hit around 120 mph. I also see that the speedometers only reach about 120 mph but mine must have had a higher maximum although i really don't recall how high. My car was in the yellow & black Mach 1 paint, 3 speed auto. Using it as a stick it would do 75 in 1st, 110 in 2nd and then fly ! Would appreciate anyone's info or similar experiences.
Roy.

dodgestang

144 KM/hr

JMD

As I understand it, England uses MPH even now....

In any case seeing as someone had brought the car to England it may have been modified to one degree or another. Apparently someone saw fit to install a 150 or 160 + speedometer, so other upgrades may have been made as well.

Also, to the best of my understanding no emission controls were required in England during this era. The removal and or negation of emission control devices and other "built in" emissionmeasures would have helped performance a lot.

The Boss 351 was available for this model year, and additionally some rare but potent heads were available which would have helped power a bunch even with a 2Vcarb.

Also there is the "chance factor", this is when a car comes off the assembly line head and shoulders above it's otherwise identical brethren with regard to performance.... I have seen this more than once!

Welcome to the forum Roy!

dodgestang

That's no fun

Since I can't go with humor I will go with someone swapped out the pumpkin and/or changed the tires making your speedo no longer all that accurate.

JMD

I could see this, combine it with thereal possibilitythat cars that felt very fast in the 70s and 80s don't seem that fast by todays standards. We have become somewhat spoiled by "easy power" these days. Easy stock power, and easy aftermarket power.

So we might remember being veryimpressed by something thatmight not feel that impressive today.

ninteen66mustang

I HIGHLY doubt your mustang made it to 144 mph and your survived to tell about it. One place did wind tunnel tests and determined that a 67 mustang would lift off the ground completely at like 150. Any old car at 144 would be extremely dangerous and is unlikely. I would guess you were doing km/hr which would be around 90 mph, which still feels fast.

royboy1952

I appreciate the info from JMD although i guess there's always one dipstick with a dumb answer (nineteen66mustang) who thinks that i don't know the difference between MPH & KPH. I have driven many fast cars before & after my 71 Mustang, which was only 7 years old at the time, not an old banger. I would also like to say that i have not taken off into the air yet !

retro77

Last time I checked 71's had better aerodynamics than a '67...

flyingfool

im looking at that 75 in fist part...all i got to say is.,..DAMN! haha..im thinking gears were tweaked, becasue that seems way to high for stock. but thats just me and my 302.

royboy1952

I guess there are reasons as well as those dodgestang mentions like lack of emmisions, the reason for fitting a 160 speedometer also had to in there somewhere. I also have to note that when it was put against a Javellin Amx with a 400 + 4bbl it accellerated quicker off the line and was never caught on a 2.5 mile run. Much appreciate those positive comments. Thanks