ddartdude,
Well I need to look in the old National Service data book. These books have the specs for about eveything, there are like 3 times as thick as the old motors and later mitchel books.
I recall it was like around .515 lift, about a 268-280 ish duration, they also had some incredible still springs and the seat pressues value closed were over 200+ lbs as I recall stood out. it had very little overlap and was a very step flanked cam. it was made by racer brown in 65-66 to compete with the 271 hp cal special 289 mustangs. There were rated at 275 hp 273, dual ex, dual point dist, 10.5: compression, same ex manifolds, same heads etc.
Now that said there were some dealer installed factory type break apart headers.
I built mine with a Isky cam that was custom made, the Mopar purple series and 340 cams killed the bottom end. I played with the 260, 270, and the origional 340 grinds. They all kinda sucked for torque.
Comp cams has some grinds that are close.
Camshaft, Mechanical Flat Tappet, Advertised Duration 274/ 280, Lift .502/ .511, Mopar, Small Block, CCA-20-230-4
Camshaft, Mechanical Flat Tappet, Advertised Duration 268/ 274, Lift .488/ .501, Mopar, Small Block, CCA-20-233-4
But if you had the money you could machine and do a better roller today I am sure with less were etc and make better power than I did.
If you look at many of the cams and grinds descriptions etc, keep in mind they are really for the larger 430-360s. DO NOT over cam, you can almost say that if it is list as extreme it is next noth up and going act like race in the little 273.
Like if you go this big:
Camshaft, Mechanical Flat Tappet, Advertised Duration 252/ 262, Lift .542/ .555, you are going to kill the power all to hell, they list it as a 3500-7000 stick, but on a 273 it is more like a 4000-7500 stick.
I think if you can go a decent set of heads with at least 360 intakes, exh, notch the block, decent heads TTI etc and a smaller solid with 10:5's pistons and tricked ignition, the 273 needs a lot of intial spark about 34 max and have it all in by 2500-3k depends on setup etc, air gap with a 600-650 max carb, or maybe a little less inteake depends what you want ou will be good. But you are going to need 3.91 or better to make her launch too.
I used to spin mine very high, had a forged 318-3 truck crank, and custom rods, windage tray and oiling mods done. 8k was not an issue, but I had rocker shafts that were bushed too.
HP to 300 HP in a 273 that can run on the street is do-able.
I will look for the specs in the book for you on the D dart 273 -275 HP cam.
