Gunfreak25

Need some RPM figures for my project. At what RPM do stock 455's peak out at? Doesn't have to be exact. I hear anywhere from 2200 to 2800.

ziff396

From what I know, 4-4500 stock. Mine isn't stock and has run 6300 a few times still pulling. This year I plan on 5k max to make her last.

cutlassefi

Torque peak or horsepower peak? 2 diffierent things.

Gunfreak25

The project in question has a Th400 and axles geared at 6.17:1. Based on the tire specs the motor will be turning 50.88 RPM's for every 1mph in this vehicle. 95% of my driving will be city stop and go at a max of 45MPH (2289rpm's). Maybe 55 or 60 when out of town. I am trying to get an idea of how badly this thing will suck the bottom of the gas tank out at such speeds. If my numbers are correct the truck should be able to do a max of 55mph to retain any sort of fuel economy. I believe this is called the "power band". It's that sweet RPM range where the motor is at it's best in both power and fuel economy.


Even though the motor has enough power to push the truck to 85+mph EASILY. The rest of the vehicles drive line was never designed to move above 58mph. Plus, anything above 60 or so and I'll bet the 455 gets MIGHTY thirsty.

pcard

See this link for torque and HP curves for 1970 stock engines.
http://wildaboutcarsonline.com/membe..._Specs_1-3.pdf

Gunfreak25

Good lord! 700lbs of torque at approx 5000rpm? Thanks for the chart, it does look like the 2800 to 3200 RPM range estimate was spot on.

MDchanic

I think that's the HP line you're looking at there.
The same motor seems to make just under 500 pounds of torque at about 3,400 RPM.

- Eric