to much gear?

[layitlow]

i have a 87 mustang with a 351W in it, and it has a 7.5 rear end, with 275/60/r15 tires and a 456 gear in it. and runs about 4500 rpm in 5th gear i THINK i was going about 45 mph, speedo dont work, should that be right, because someone told me that was too much gear for the motor,

[theyallslow]

well...i would say it was a bit much.

[zzambucca]

Is the engine stock? What is the redline? That tire is about 28 inches tall, which is a tall tire, which should take away some of the gear. You cannot go by the speedo unless you changed it for tire height and gears. Find someone to drive beside you and see what the RPM is at around 60. If this is a stock engine, and your revving over 4000 at 60, I would definitely say its too much gear for a daily car.

[WCKDGT]

i wld say just a bit

[layitlow]

Is the engine stock? What is the redline? That tire is about 28 inches tall, which is a tall tire, which should take away some of the gear. You cannot go by the speedo unless you changed it for tire height and gears. Find someone to drive beside you and see what the RPM is at around 60. If this is a stock engine, and your revving over 4000 at 60, I would definitely say its too much gear for a daily car.

well it has ,cam,roller rockers. headers, intake,a really good set of heads exc.... but we dont know a whole lot about the motor got the motor complete with the car, so all we did was put it in, pretty much the bottem end is stock,but ya im going to have someone drive beside me to see how fast im going, and its more of a weekend car, hears a pic of the engine so you get a ideal. i just dont want it to blow up going down the road, its a brand new engine

[Paul408Notch]

So if it's running 4500rpms in 5th at 45mph, it would be at like 6500rpms at 65mph? I'd say that could be a little steep of a gear. Maybe you should consider an 8.8 and some 3.55s or 3.73s.

[ponyboystroker]

something doesn't sound right here. I thought that 4.10 5.0 cars ran about 3,000 RPMs at 65 mph. I can't see your car taching that much higher with only a little more gear. What tach are you looking at, the stock one or an after market one?

[layitlow]

something doesn't sound right here. I thought that 4.10 5.0 cars ran about 3,000 RPMs at 65 mph. I can't see your car taching that much higher with only a little more gear. What tach are you looking at, the stock one or an after market one?

after market one, now my question is do you guys think this is taking away the performance from the motor,like on the drag strip, would it probly be faster with a different gear?

[ponyboystroker]

this may seem like a dumb question but did you set the switch on the tachs for an 8 cylinder?

[layitlow]

this may seem like a dumb question but did you set the switch on the tachs for an 8 cylinder?

ya we evan tryed another tach, and they both said the samething, and they were both hooked up right. thats whay my dads friend said " its my dads car" that the rpm shouldnt be that high, but he also said it shouldnt be able to spin the tires through second gear the motor is supposed to be a low 12'sec engine, thats what we were told. it redlines about around 7500 to 8000 rpm