'A-Body Showdown' ~ 273 'Commando' vs. 318 2-Barrel
A-Body Showdown
273/235 HP 'Commando' vs. 318/230 HP 2-Barrel
1967 Barracuda 'Fastback' ........ #2940 lbs. ~ 235 HP = 12.51 Wt/HP
vs.
1968 Barracuda 'Notchback' ...... #2893 lbs. ~ 230 HP = 12.58 Wt/HP
Near equal in Weight-to-Horsepower Factors.
273 'Commando'
235 HP @ 5200 RPM's
280 Ft/Lbs. of Torque @ 4000 RPM's
318 ~ 2-Barrel
230 HP @ 4400 RPM's
340 Ft/Lbs. of Torque @ 2400 RPM's
"Let The Fish Begin To Swim"
Assuming identical cars but for engines;the same trannys and rearends, etc:
Check out the the 273 torque at 4000 rpm; namely 280#. If Mopar's numbers were gospel , 280x4000/3450=213 hp. The 273 climbed from barely enough torque to idle, up to 213 hp @4000.
Now look at the teener. With a power peak at 4400, there is a good chance that with the factory cam, she was already making 98% of that at 4000, so225hp.This is 5.6% better than the 273.
Now we all know a teener pulls like a freight-train compared to a 273, so up to this point and a little further the 318 is well out in front, with it's 2bbl. With a 2.76 and a 2.45 low gear, this is about 43 mph.
My guess is that the 318 will continue to 4400, and then to 4800 still at 96% of peak-power. So now we are up to 51 mph, and sitting at 221hp.The teener is done, out front, but is gonna have to shift. And when it does the Rs will fall to 2841,maybe 175 hp.
By this time the 273 is starting to make power, perhaps pulling 94% of peak power, so 221 hp.So now the 273 is catching up, and is not gonna shift until 6200@66mph. So somewhere around 55mph the 273 gets ahead of the 318. Now it has to shift, and the Rs fall to 3670@176hp.
So now they are pulling from the same hp.
But the teener is building power faster than the 273 so it begins catching up some. The finish-line is at about 75/80 mph.The teener may have caught up by then as its power peak comes at 79mph. while the 273 will not reach it's 235 hp until 94 mph.
Unless you are racing to between 55 and 66 mph, I think it will be teener first, thru the traps.
