Usable power for the street?
What do you consider good steerable power?
The easy answer is 10/11pounds per horsepower is a lotta fun.
by 13#/hp, things are slowing down.
By 16# I want no part of it no matter what gears are in it
At 2800 pounds, that would be 255 to 280hp
The thing is this number can be had, 7ways from tuesday.
With a 273 you are looking at 280/273=1.026 hp per cube, which means that she will need to be revving pretty high to get the number. And that points to it being a challenge to combo up in the 2800pound street car; yur looking at rear gears, front gears, stall, and forget about fuel-economy.
With a 360 it works out to .78 hp per cube,s o it combos up, cheap and easy; just run whatever you have, behind it.
318s and 340s are somewhere in between.
I am currently at ~9.1 pounds per hp, and this is borderline overkill.
========================
One combo I really liked was a 340, done up like a 318; it had torque out the wazoo, in a 65 V100Wagon, made great fuel-economy with the 318 cam, and revved to the moon.
I drove that car everywhere man.
=======================
IMO your question should be a lil different.
For a streeter, IMO horsepower is sortof not very important, cuz you only ever go thru the power peak once on the way to the speed-limit, and the tires are usually spinning..
More important IMO is the cubes per pound, which is the great low-rpm equalizer.
2800/273 is ho hum at 10.25 pounds per cube.
2800/318 is 8.8 getting somewhere
2800/340 is 8.2 a lil better for sure, and a lotta fun already
2800/360 is 7.78, which has the potential to scare the crap outta you, but because of the longer stroke, you can run less gear and get back to making fuel-economy.
The 340 is the universal go to, because you can move it up or down in the power versus economy war, to better fit your combo to your goals, and it's hard to ignore the potential of the 4.04 bores.
In a streeter, there is IMO, no good reason to run a 340 cam in an Early-A. You can easily detune a 340 down to say 250 hp and have a lotta lotta fun at 2800/250=11.2 pounds per hp. But same engine with a new cam and some bolt-ons can easily go to 350hp, and 2800/350=8 pounds per hp, putting you on a higher level than my 3650/400=9.12 combo.
So then you can see that a 340 has the potential to go either way, and can grow with you. I mean you could match it to almost any heads you want to, and or almost any street cam, so long as you are mindful of the pressure to octane limits.
IMO, a 360 in a lightweight-A could be overkill due to tirespin going to long past the speed limit, which can already be dangerous at 30/40 mph. Yeah the 340 can do that too, but dressed the same, the bottom will be a lil softer. For your stared purpose;
I’m not looking to race the car, but do want to be able to break the tires loose easily from time to time and launch hard.
even a 318 could do it, albeit requiring a bit more gear, unless you cave a Commando 4-speed with it's 3.09 low gear.
If you already had a 318/5.2, I see no reason not to use it.
If all you have is the 273, I would not "bother with it", unless: you are not at all concerned with being overly quick. With the 3.09 low you can run 3.23s and still bust the tires loose in first gear, if not, just run skinnier tires, until you get what you want..
If you have to buy a used engine, 360s/5.9s are cheap and easy; just drop it and go.
If you have an opportunity to grab a 340, IMO that is the one, even if only a shortblock, and dress the top with whatever..
Always, no matter what engine you use, be advised that each one may require a different flywheel balance and/or ; there may be a challenge to hook the 4-speed to it.
