HP limit for a real "street" car?

[Chase383]

Hey guys,

Now I know the answer to my question is highly subjective, but in your opinion what is the upper limit of horsepower that you'd have in a B-body that sees mostly street use. Now notice I didn't say "pass inspection".... because "race" cars that can sorta drive on the street while getting 4mpg with super loose converters and 5.13 gears don't count.

I mean you look outside, weather is half way decent, and you say "screw the daily driver, I'm taking ______"

Not "I hope it doesn't start to rain or I'm in trouble" or " I hope I don't see a cop because if I don't feather the gas/clutch just right, I'll spin the tires"....


Just curious?

 

[ykf7b0]

The horsepower rating could go really high (possibly 600-700) but for me it would be a car that I can drive 35 miles to work one way on pump gas, drive the speed limits without taching 4000 rpm, and not burn a whole tank of fuel to make the 70 mile round trip.

 

[Budnicks]

Let me see, sounds like you want about a real 400+ rear wheel-hp/driver combo {could push it to 500-hp easily, if need be}, performance 101, with the proper size & style headers/exhaust, free flowing K&N air-filter, good oiling system/pan pump etc., hwy friendly & performance compromise gears like 3.73:1 {3.91:1 with tall enough tires or O/D}, good rims/tires, tied together front & rear sub-frame connectors, a slightly looser converter/tighter clutch, trans {o/d optional}, properly sized appropriate intake/induction system, proper type fuel supply system & lines regulator etc. & especially good quality ported cylinder heads {that's where you make the most useable/efficient power} & hot ignition & coil, with low ohm resistance plug wires, to burn that fuel properly, but still reliable & street-able, still fast/quick like low 13 second ET range, depends on the weight of the car per/hp, a lighter car properly set up, maybe mid-high 12's {respectable performance, like you said not a racecar}, but still not too radical, still can drive with out too much worry, not have to pull a tanker truck behind you, but still able to beat the occasional guy who pisses you off... my car has about 600hp & 600ftlbs TQ it's completely street-able/drivable, doesn't get hot, gets about 14mpg driving on the center 350cfm+2bbl & if I don't drive like a maniac or open the other 2/500+cfm outboard carbs... I guess it just depends on what's enough for you or what you expect out of your car, what's your budget, what kind of style... IMHFO It's a bare min. of about $15-$20 per/hp {double that for a Hemi probably}, just to do it right & have it last {if you do the work yourself, more if you have to pay someone else} & have all the proper supporting parts in all the proper places for all the added power... remember the more motor, the more everywhere else needs to be beefed up... 550hp range your getting into a realm of not really a "true" durable dependable street car anymore, with out spending allot of $$$, like near double the $$$$, without allot of extra $$$$, realistically a mild 470-500ci stroker or smaller CI turbocharged or centrifugal supercharger with EFI, will probably be the easiest way, to meat all your criteria, still be very street-able & have that kind of power/dependablity &/or a much, much lighter car, so you don't need big HP to push it easily...

 

[Chase383]

Actually I hadn't even give mpg much thought... but I'd hope for 8-10 mpg minimum.

I was thinking in the 500-550 hp range, with an 18-spine 833, 3.54 Dana and as much tire as I can stuff in the back without cutting or rubbing. Cost is gonna hurt no matter what... because right now I have wide valvecover lust....

 

[Grabinov911]

Interesting. $15 to $20 per HP. Never thought about it that way. Should put me right between 550 and 600HP! LOL - I hope...

 

[Budnicks]

I was thinking in the 500-550 hp range, with an 18-spine 833, 3.54 Dana and as much tire as I can stuff in the back without cutting or rubbing. Cost is gonna hurt no matter what... because right now I have wide valvecover lust....

with a hemi you can double that build cost at-least

- - - Updated - - -

Actually I hadn't even give mpg much thought... but I'd hope for 8-10 mpg minimum.

what's your actual definition of a street car ??

- - - Updated - - -

Interesting. $15 to $20 per HP. Never thought about it that way. Should put me right between 550 and 600HP! LOL - I hope...

that's a baseline #, if you can do most the work yourself

 

[Chase383]

with a hemi you can double that build cost at-least

- - - Updated - - -

what's your actual definition of a street car ??

So I'm finding $$$$ wise, I keep adding up the numbers minus the intake, carbs, aircleaner, valvecovers and exhaust manifolds to try and fool myself into thinking it won't cost as much as it will. The significant other told me this was the last project I was dragging home... she doesn't care what I do with it, or how much it costs as long as I'm happy with it. But no more musical projects getting bought and sold every few years. And my 1971 Plymouth has to mild enough that she can drive it to shows... thats compromise, right? :grin:


My definition of a street car is:

Something that can be driven on fair weather days.

Something that will not overheat in traffic.

An engine that will support power brakes.

Something that gets at least close to double digit mpg with conservative driving.

Something that does not simply overwhelm street tires to the point you might as well block off the secondaries because they will never open on the street.

Runs on pump premium.

Something that doesn't stomped by a new 5.0 Mustang or Camaro SS.



I have very little "butt" time in a vintage Mopar right now, most of my projects have been non runners/drivers. My one driving project at least moved under its own power, but the with a dead spot in the steering half a turn of the wheel wide, and almost no brakes, even a 383 2 barrel seems scary!

 

[Budnicks]

a properly tuned & well set up 383ci RR/Super Bee will dust a basic 5.0 Mustang or a Camaro SS, that's no real secret, for the newer/better/ faster more powerful Stang & Camaro, you'll need a decent suspension/shocks etc., traction aid/good tires, good driver & good tuning, gears, cam & valve train properly spec.'d, a good adequate sized fuel system/pump, intake & carb, good hot ignition & professional head work/porting, good converter or clutch, headers & free flowing exhaust, free flowing K&N filter, 93 pump gas...

 

[Tempest 455]

It's hard to pin down a number because ci has a major impact on your question. A really big motor can retain some of the streetable factor and still make a lot of HP/TQ. From having been there and done that, and wish I had not. For rough figures, I would keep it under 600. A 500 HP motor is a heck of a lot of fun on the street and with the right gear/converter you should be able to drive anywhere.

Cost of gas will be your biggest problem.

 

[rumblefish360]

How much? Until you can no longer control it and crap your pants thinking about getting into the car.

 

[eric383]

If it were me I would aim for around 400 HP out of a 440 and choose a cam and build your engine around it especially if you need enough vacuum for power brakes. It is very easy to get caught up in the horsepower game and as Propwash once said "turn your bank account into a funeral pyre". Like I told a buddy of mine who was complaining about his 318 but didn't have the cash to upgrade to something else "remember you are not out to win a bunch of races but just enjoy your classic car". No matter where you go there will always be someone with a bigger, badder engine. To keep my costs down I always look at the classifieds on FBBO, Craigslist, fleabay, etc. Just a little insight from a guy who has been there. Good luck with your build.

 

[Dako]

There's much more to your equation than 'what's the max horepower?'. You can have 500hp, a 3,500rpm stall tq converter with 2.76 gearing and the car is still 'drivable'. You can also have 300hp, a 4 spd, with 3.73 gearing and the car be very squirrelly on dry pavement when pushed. You would need to provide the info on what other components you plan to run (transmission info, rear end gearing, tire size) to get a good answer.

Example 1: I have a 'mildly' built Poly 318 in my `66 Belvedere II with auto trans and 255/60x15 tires. With the original 2.94 gears it would not break the tires loose, but would run from 20mph on up, real good. I swapped in 3.55 gears and now the tires break loose on dry pavement with the mash of the 'skinny pedal'.

Example 2: I had a `70 Duster 340...stock motor, auto trans, 3.23 gearing, and 195/70x14 tires. With these tires, I could not launch without roasting the tires...I had to accelerate quickly then go full full throttle once I got it up to 20mph. I swapped out to 245/60x14 tires and was able to 'hook up' much better on the launch.

So, what trans, gears, tires do you plan to run?

- - - Updated - - -

Actually I hadn't even give mpg much thought... but I'd hope for 8-10 mpg minimum.

I was thinking in the 500-550 hp range, with an 18-spine 833, 3.54 Dana and as much tire as I can stuff in the back without cutting or rubbing. Cost is gonna hurt no matter what... because right now I have wide valvecover lust....

Sorry, missed this before making my previous post. Anything over 400hp, and you better have some good driving skills. With even slightly aggressive throttle response at low speeds, tire spin potential will be like driving on wet pavement. As long as you are aware and don't try to make any quick attempts to get out into moving traffic from a standstill you will be okay. I'm not saying over 400hp is too much, you just need to be aware that with a 4spd and 3.54 gearing, the driving characteristics change significantly.

 

[lewtot184]

How much? Until you can no longer control it and crap your pants thinking about getting into the car.

this is pretty realistic. to me a real street car will run on pump gas, cruise at 70mph on the interstate, no high maintenance stuff, suspension that will safely go around corners, reasonable brakes and steering. i have a '65 coronet, 440 with a 6-pak, small mech cam, good heads and exhaust, auto, 3.23 gear, street hemi suspension. everything works (lights, wipers, heater), no safety issues. i'm somewhat reserved on horsepower numbers and don't buy into the magazine/internet numbers for the most part. my engine probably averages 475hp, may go a little higher or lower depending on the air. to me this is about the max for a streetable suspension, sensible tire combo (no skinnies up front and no fattys in the back). i guarantee you that you will hold onto the steering wheel when nailing the carbs in 1st gear and may end up in a ditch on the 1st to 2nd gear shift. 500hp/500+lbft of torque at the crank will easily overpower any street suspension.

 

[themechanic]

I enjoy driving my 44 year old muscle car. I drive a 1969 Coronet R/T with a stock 440. I've never had anyone try to get me to race on the street. They just give me a thumbs up and drive on.

If it ain't broke....drive it til it is. Then, if you're so inclined, spend all that money you saved up on a mild stroker.

 

[70rr-brian]

For what its worth, my roadrunner has 555 hp and 630 tq and that is about the limit of what I would do for the street in one of these old cars with stock suspensions. The high stall is a pain sometimes. I run 3.55 gears which really should be 3.91's so it can drive down the interstate without being at 4k. All stock suspension and drum brakes. I don't feel unsafe in it unless I floor it below 60mph because its gets all squirrely. But it is still fun to drive.

 

[Dennis H]

9.5:1. 2150 rpm @ 70 mph. 415 RWHP Chassis Dyno. Drive anywhere. Pump gas, ran 85 one time. High teen mileage if you drive "right, I don't drive right often though. Got caught in the rain on the way home from work, no problem. Guys I hang around with define "street different. Race gas and constant tuning and adjusting. I'd rather have reliability. Pic is a Terribles Sands in Reno. Should be horrible awful terribles.

 

[Dako]

For what its worth, my roadrunner has 555 hp and 630 tq and that is about the limit of what I would do for the street in one of these old cars with stock suspensions. The high stall is a pain sometimes. I run 3.55 gears which really should be 3.91's so it can drive down the interstate without being at 4k. All stock suspension and drum brakes. I don't feel unsafe in it unless I floor it below 60mph because its gets all squirrely. But it is still fun to drive.

If you go from 3.55s to 3.91s your rpm will go even higher...

 

[daredevil]

I,d also say 5-600 horse naturally aspirated, That would jump to 800 to a thousand for a turbo car.

- - - Updated - - -

If you go from 3.55s to 3.91s your rpm will go even higher...

yep you could use 3.23s

 

[70bigblockdodge]

I would say there is no real "limit" but more of a drivability, comfort, durability issue.

1) big converter and big gears can make anything feel an run fast, but they are miserable unless you live next door to your favorite cruise spot
2)interior, seats, hvac, sound deadener, undercoat, full exhaust remove any to all of these car will go faster have better mileage but also become more miserable-not fun
3) you can push the limits higher and higher in a engine, this makes parts breakage more common, hard to be a street car when on shoulder waiting for hook. Another drawback is more exotic parts in engine and car for that matter if you are away from home sitting and waiting for the ups man is not practical read: parts available at the part store, rocker arms, pushrods, brake pads, master cylinders, dist caps, the list goes on.
4) overdrives are the single best thing of high hp and street car living together, low cruising rpm, better mpg, less wear and tear, less noise and vibration. you mentioned a 18 spline trans if you have it I would sell it and turn that into a 5 speed, if you don't already have it save your money and search time and get a 5 speed you'll be happy which will make your sig. other happy and its easier to drive than the 18 spline MO.

 

[70rr-brian]

If you go from 3.55s to 3.91s your rpm will go even higher...

Yeah I know. I just phrased it badly. What I was saying is I am running 3.55's to keep the RPM's down but my setup really demands a 3.91 with the 3800 stall.

yep you could use 3.23s

That's pretty much out of the question for my setup. The cam demands a high stall and with the 3.55's when you get caught at low RPM/speed in second gear its flashing to 4k and barely able to get out of its own way. I could mash it to get a kickdown into 1st....but that causes massive tire spin and the car to starting sliding sideways down the street. While I don't necessarily have a problem with that...local law enforcement does.