Usable power for the street?

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ValleyRat

ValleyRat

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Hey everyone, first off, I really appreciate all the feedback I get on this forum. I really value your opinions, so I’m coming back with another question…

What do you consider good steerable power?

I currently have a 273 Charger motor (1967) and an 833 4 speed trans for my ‘67 Barracuda (unknown rear gears).

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. I keep hearing people tell me “get a 360 if you want power.” From my reading, a mildly built 360 can make about 350 hp (cam, intake, headers).

Is that getting to be overkill for a street car?

I’ve never been in a car with a 273 Commando, so I don’t have any point of reference aside from what I’ve read. I know the common adage is always “more is better,” but I’m curious to hear what your thoughts are.

In my area, I can buy a running 5.9 magnum for around $700, after dressing it with a carbureted intake, cam, headers, and new carb, I’m nearing $2300… while I can have my 273 together for around $1700 (boring cylinders, a new cam/lifters).

Thanks again everyone, you guys really help me with these decisions.
 
Steetable depends on many many factors. There is no number that is all encompassing. My daily driver 3500 dually makes 705hp to the tire. But it weighs 7600 pounds. Completely streetable. My 63 falcon makes just over 600 and weighs 2650 and is terrifying. It’s all relative. For a stockish A body with a small block the fun really starts at about 400hp and a 360 magnum will get there a whole lot easier and be much more steerable than a 273 will. Just my opinion.
 
Hey VR, post some pics of your Barracuda. Everyone on FABO loves pics.
You mentioned your existing 273 and transmission, but didn't mention what rear end is currently in the car. That's going to be another prime consideration. A 7.25 differential may not hold up to your 273 Commando. A 8.25 may be good for a stock-built 273 but may be marginal for a stout 273. If you want to go to a built 360 or even a stock 5.9 Magnum then I'd be looking at a 8.75 to live behind either of those.
 
ValleyRat said:
What do you consider good steerable power?
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ValleyRat said:
Is that getting to be overkill for a street car?
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Everyone will have a different opinion on this, but it really amounts to what YOU will be happy with.
Talk to some local guys, club members, friends; see if you can go for a ridealong in their cars. Compare notes between them to come up with some basics that make YOU happy.
Remember, there's more to it than just horsepower- on the street torque is king, and is what is going to keep that silly grin on your face. To that end, a nice torquey cam and some rear gears around 3.55 will go a long way towards that end; a little looser of a torque convertor as well if you're running an automatic.
ValleyRat said:
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.
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Think of it this way, I had an old C10 pickup with a tired smogger 307 and 3 on the tree and 3.70 ish gears that could break the tires loose at will, and if I threw a few engine blocks in the back would hook so hard it would snap your head back. Not exactly a horsepower machine.
So get some real-world, seat of the pants exposure and see what you like- "more is better" isn't always necessary.
And since you asked, in an A body I enjoy about 1hp-1ft.lb./c.i. to start, and gears around 3.55 for smaller engines and 3.23s for bigger ones- nice street manners and still able to defend her honor when needed. Not a world beater, but not a wallet-eater and still fun.
JMO.
 
Like Professor Fate just said above, the right rear end gear means a whole LOT!!!!
and.. Kind of like the guy that wanted to change out his slant to a V8... he said, wow! I never realized what all that would require to be changed!
 
Professor Fate said:
Everyone will have a different opinion on this, but it really amounts to what YOU will be happy with.
Talk to some local guys, club members, friends; see if you can go for a ridealong in their cars. Compare notes between them to come up with some basics that make YOU happy.
Remember, there's more to it than just horsepower- on the street torque is king, and is what is going to keep that silly grin on your face. To that end, a nice torquey cam and some rear gears around 3.55 will go a long way towards that end; a little looser of a torque convertor as well if you're running an automatic.

Think of it this way, I had an old C10 pickup with a tired smogger 307 and 3 on the tree and 3.70 ish gears that could break the tires loose at will, and if I threw a few engine blocks in the back would hook so hard it would snap your head back. Not exactly a horsepower machine.
So get some real-world, seat of the pants exposure and see what you like- "more is better" isn't always necessary.
And since you asked, in an A body I enjoy about 1hp-1ft.lb./c.i. to start, and gears around 3.55 for smaller engines and 3.23s for bigger ones- nice street manners and still able to defend her honor when needed. Not a world beater, but not a wallet-eater and still fun.
JMO.
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You make a great point about the rear gears, I’ll roll under the car and see if the tags are still present. I’d imagine the 273 with proper gearing and a 4 speed wouldn’t be anything to scoff at. Part of me does enjoy the uniqueness of that motor, compared to the more modern 5.9 Magnum dressed up to look like an old LA.
 
Fender tag says AX, and underneath is the number 2. I’m assuming that is a 2.94 rear axel with an open diff? The car was originally a 6 cylinder…
 
My guess is 3.23 or 3.55 gears but if you got 67 "S" you may have 3.91 SG gears

Just read your post. 2.76 or 2.93...terrible 273 gears! Get some 3.55's and then make your motor decision. 273/4 is a beloved motor, they like to rev but are soft down low but a 4sp will make up for that.
 
ValleyRat said:
Hey everyone, first off, I really appreciate all the feedback I get on this forum. I really value your opinions, so I’m coming back with another question…

What do you consider good steerable power?

I currently have a 273 Charger motor (1967) and an 833 4 speed trans for my ‘67 Barracuda (unknown rear gears).

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. I keep hearing people tell me “get a 360 if you want power.” From my reading, a mildly built 360 can make about 350 hp (cam, intake, headers).

Is that getting to be overkill for a street car?

I’ve never been in a car with a 273 Commando, so I don’t have any point of reference aside from what I’ve read. I know the common adage is always “more is better,” but I’m curious to hear what your thoughts are.

In my area, I can buy a running 5.9 magnum for around $700, after dressing it with a carbureted intake, cam, headers, and new carb, I’m nearing $2300… while I can have my 273 together for around $1700 (boring cylinders, a new cam/lifters).

Thanks again everyone, you guys really help me with these decisions.
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The extra price will produce a much better experience and power. What I myself did was I grabbed a ‘00-5.9 Magnum engine, gave it a 750 AFB carb, rpm intake, headers (1-3/4 tube) into a dual exhaust @ 2-1/2 inches.
A MP chrome box fires the JY distributor.

The trans is a 727 w/a 3.55 geared rear riding on 245/60/15’s. (26-1/2 inch tire) This set up is in a ‘79 Magnum, B body.

This is equal to what MP sold a while back as there 300hp crate engine. But with a better intake. From here, it will get a camshaft.

Add valve springs and a cam for more HP. A mild one will be really nice. The stock cam rolls over at 4500 rpm. A cam of approximately 218*’s @.050 will add 500+ rpm. Is very streetable with good mileage.
 
ValleyRat said:
Fender tag says AX, and underneath is the number 2. I’m assuming that is a 2.94 rear axel with an open diff? The car was originally a 6 cylinder…
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Correct. If the axle wasn't changed.

273 with the 4 speed can be plenty perky on the street. Keep the tire diameter same as factory to help with acceleration. D70-14 for '67 was the biggest. Thats around 205r70-14. 215r70-14 would be OK too, but IMO not with a 2.94 rear.

Horsepower is really about high rpm. The big numbers at 6500 or even 5500 rpm don't give a good indication of street throttle response and fun factor. You'll notice that hp only when passing on the interstate to some extent, and to a great extent when running 1/4 mile.
 
A bone stock 5.9 Magnum with a 750 double pumper, air gap manifold and long tube headers will be all over 350HP without breathin hard.
 
ValleyRat said:
What do you consider good steerable power?
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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.
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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.
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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;
ValleyRat said:
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.
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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.
 
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pishta said:
My guess is 3.23 or 3.55 gears but if you got 67 "S" you may have 3.91 SG gears

Just read your post. 2.76 or 2.93...terrible 273 gears! Get some 3.55's and then make your motor decision. 273/4 is a beloved motor, they like to rev but are soft down low but a 4sp will make up for that.
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And this is where this thread should end. Going from 2.73 to 3:55 will be a noticeable difference. However I’ll chime in for the OP and say with a small block 350-450 hp is just fine on the street. Mine makes 415 hp and 430 ft lbs and cruises just fine.
 
RustyRatRod said:
Who even gives a chit? I mean seriously.
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The thing I find totally and completely laughable is his outer space idea that he will be “Spinning tires” as if he has no control over the throttle. Not to mention what suspension he has, even if stock and what tires he is running, even if there greasy BFG’s.
 
rumblefish360 said:
The thing I find totally and completely laughable is his outer space idea that he will be “Spinning tires” as if he has no control over the throttle. Not to mention what suspension he has, even if stock and what tires he is running, even if there greasy BFG’s.
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I stopped caring long, long ago. It's really obvious what he is.....to me. .....and several others here.
 
From a dumb young guy in this wacky mopar world... build a 360 with intake, headers and exhaust... you will have a blast... but you'll soon want more and more... and more. I'm on a mild 340 build right now, mopar magazine did the same exact build had it at like 400hp. It lasted almost 2 years. Now doing more to it for some more power...
 
Also, I agree with what was said above. Torque converter and gears are huge! I was cheap and haven't invested in a converter yet but will. I have 3.23 gears and sure grip. I spin all the way through 1st and into 2nd, but I still dont have enough kick you in throat power... soon :)
 
DentalDart said:
Also, I agree with what was said above. Torque converter and gears are huge! I was cheap and haven't invested in a converter yet but will. I have 3.23 gears and sure grip. I spin all the way through 1st and into 2nd, but I still dont have enough kick you in throat power... soon :)
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It's just not something to get the slide rule and calculators out to figure out. 220-236 @.050 on a 108-112 LSA with 9:1 compression with a decent carburetor intake and headers will make any first timer or even seasoned car guy grin from ear to ear. I could pick parts out tonight in 10 minutes that'd give a guaranteed 350-360HP with no sweat.....yet guys come on here and get driven crazy by people who may not even have a CAR over what parts to use. It's just not that difficult. You've found it out first hand.
 
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id rather have 350hp 370ish tq a converter or a clutch,....and gears over 500 hp 550 tq and 2:90ish gears!! with that said,.. a real 400 hp enuff for the street!
 
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