So I have a 65 with a 120 speedo. Ive had it up to an easy 110 but not any faster, but I feel like I could easily go faster but I dont want to die...yet How fast do you honestly think a 65 mustang could go? Just out of curiosity (and im buying a speedo gauge and i dunno if i should buy 120 or 140 or 160<-- NOT!)

 

Depends on gearing, rpm, aerodynamic drag, and power. Up to around 130-140mph its somewhat easier to go faster than it is over 140mph. You will need ALOT of power in older cars to run 160mph, plus the gears and rpm to do it. You dont need nearly as much to run 110 or even 120. Its completely feseable that with a 300hp engine you can run 120mph with a 65 Stang.

More aero cars will go faster with less power, such as 4th gen F bodys and Ford GT's, but they still push quite alot of air.

Years back I had some guys tellin me that the 85 Cutlass with a 260 ci v8 would do 160, sorry but stock its just not going to happen. 110 is workin for that combination, even more so than your Mustang, since its a larger car with greater frontal area.

As for the speedo, well the 160 looks cool, even if your car never sees it... its personal preference in most cases..

 

You ain't gonna get much faster than 110 with a stock set up.

 

thanks for the replies, but, what about with these mods (soon to come!) RPM Intake 4 Brl carb (650 i think) and a cam (mild-moderate cam i dont know much about them) ? how fast? sounds like the 140 is PLENTY (160 makes it look like i can go way faster than i can, can you say "ricer" hehe). Thanks guys!

 

i know a guy with a couple 66 mustangs and he said once you hit about 115 it starts to lift the front end, and thats not good when your going 115 mph.

 

I think acceleration is more important that top speed. Do you really need to go 140? Not really...but slamming u back in the seat is pretty cool...

 

I'm an old fart, so I remember the olden days. I had a 67 fastback that would do 125 on radar, and that wasn't completely all out, but the 'Bama state trooper thought it was as fast as I should have it. I've got a 65 fastback now, but it never gets above around 80 or so, due to suspension, and the wisdom of age, even though it has a factory 160 speedo.

 

You'll be facing more aerodynamic problems that you will power problems. Due to the design of a stock 1st gen Mustang, you really don't want to push more than 120. If you enhance the aerodynamics, you could easily be comfortable above that. I had no problem cruising 140 in my '71 for an extended stretch of road (middle of nowhere...literally), but it had the front lowered to keep air out from under the car.

A local race shop could help you set your car up aerodynamically. But, being able to have the room to cruise at those speeds is a rarity, so I'd personally build it for torque. My '71 will now only run 120 mph before the rev limiter kicks in...but it is a fun ride up to that speed.

 

160 speedo? never heard of a 160 u mean 140?

 

Why do you need to go that fast unless you are building a racecar? I personally would not like to get my car up that fast because that just increases my chances of destroying it.