A big factor in my definition of "streetability" is throttle-response. I like a nice, linear throttle. Unfortunately, when a camshaft makes an engine "peakier", trading for higher rpm power at the expense of low-end torque, you need a converter with a higher stall, which deadens throttle-response below the stall-speed.

So while the car is faster when you've got your foot all the way to the floor and the engine is wailing and the tires are screeching and the exhaust is bellowing, the car is actually slower when you've got your foot a 1/4-way to the floor trying to go from 25mph-40mph in top gear. If you've ever driven a car with a slipping clutch or transmission, that's what a high-stall converter feels like at part-throttle and low-rpms. Now of course, you could always just floor it anytime you want to gain any speed, which is lots of fun, for about the first five minutes in traffic, but after a while, treating your gas-pedal as an on/off switch gets tiring.

For your car, If you're going with an OD transmission, I'd suggest steeper rear gears (3.73's or numerically higher) and a tighter converter (stock or no more than 2000rpm stall) to maintain that low-speed, around-town throttle-response.

The car that my '71 replaced was powered by a race motor that came out of a sand-dragster: ~470ci, 110-octane drinking beast without enough vacuum to effectively serve the power brakes and that was difficult to keep running cool for more than 20 minutes at a time. It was a lot of fun to walk it off the line and then lose traction again at 40mph in first gear when it started to get up on the cam (it had 2.56 rear gears), but with its chokeless Holley carb, just getting it going was an adventure, and with the Purple Hornies header-mufflers, it was one that the whole neighborhood got to hear (whether they wanted to or not). I'd gotten used to popping it into neutral and blipping the throttle to build some vacuum for the brakes before every stop-sign, but again, it was just something else to think about. Plus, living in a city I start endangering others if I drove the thing at more than 1/3-throttle for a few seconds at a time. With all the hassle, I never drove the thing much at all.

OTOH, I drive my base-motor '71 every chance I get, and at basically the same speeds as my race-motor monster; it's a lot more enjoyable overall.

 

I ran a 10 sec. street legal race car w/ a bored, built 427 w/ a tunnel ram, 2 4s, full race cam, magneto, slicks, etc.
Ran on pump gas, did not overheat & lic. plates.
Very streetable.


Others would disagree, not a car for most drivers.

People that followed (w/ me waiting on them) complained that min. speed was 40 & normally 80+.
Rob So what does that mean- in & out w/ the clutch to keep running at low speeds, high rpm high power setup.
So for streetability, one would do a setup (CAM, ETC.) for the rpm range one uses.

 

Thanks guys!

Lots of good thought-provoking info here.

I DO NOT intend to "race" the car. I drove it for the first time yesterday, and thanks to you guys, I am finally understanding the concept of "stall", with respect to the converter. I think I have a 2400 rpm converter, but will check with the folks who built my transmission.

I certainly dont want to have to go to mid-throttle to get from light to light!! Not with the Hookers and capped STS baffles. I dont commute to work, this will be a year-round driver, and I want it to NOT be a pain to drive around town.

Someone above mentioned gas mileage. That is important to me as well. I have thought of going to slightly steeper gears (currently stock 3.08) but I am wondering how far to go without sacrificing fuel mileage TOO much. And yes, I know its all a trade-off, and its hard to have it both ways! I am familiar with the RPM tables on BTO's website. I should be running around 1700 RPM at around 60 with my 2004R and 3.08's and 60-series tires. That seems great for cruising, but still seems a little low to me (but what do I know??) I am clueless as to whether my mid and top end (for passing, merging, etc) hp/tq will be "acceptable" with my (355 crank hp/405 crank tq) ZZ4 and my trans/rear. I'm sure it is more than enough!

Just looking for a suitable compromise... Maybe I already have it, time will tell.

I am jumping the gun a little, but have read that some folks are "disappointed" with the ZZ4 performance. I'm sure it will make me grin!!

This forum is about getting smarter. I'm trying, so thanks for everyone's input!!

Rob

 

What really matters is the rpm at which the engine is making that power, and what power it is making at your cruising RPM.

Honestly, 1700rpm is going to be LUGGING that engine; heck, with my chipped Powerstroke diesel, 1700rpm is almost lugging the engine!

And as a rule, you don't want your cruise rpm to be lower than your converter stall-speed; even if you alleviate the overheating problem (due to the constant slip from being below the stall-speed) through a lock-up converter, you're going to get a "lag" everytime you move the throttle with that combination and short of pegging the gas every time you want to change speed, your car will feel about as powerful at part-throttle as a 1996 V-6 Taurus while cruising down the highway.

A 2200-2500rpm cruise-speed is likely to be far more reasonable for a motor like that, and an 1800-2000rpm stall converter would complement that nicely.

And lower-rpm is not always better for fuel-mileage; if you're lugging the engine, you have to give it more throttle to maintain that speed than if you geared it to let the engine work in the fat part of its torque-curve, where you can maintain speed with less throttle-opening.

The best thing would be to consult your engine's dyno chart, and try to get your cruise-speed not too far below your peak-torque rpm; that would improve "streetability" as well as fuel-mileage.

But I don't think you'll be falling into economy-car mpg's, no matter what you do...

 

There are different levels of streetability...

has anyone mentioned noise or ride quality?

 

You drive a muscle car as well, so no need to ostracize yourself from the group, your one of us too.

I agree with what others have said, but in my opinion it's terminology.

The term "streetability" is a bit misleading as it kinda incorporates and infers "practical", "drivability", and "street legal" all together.

Basically how tame vs wild a car is.

If you start upgrading you 'may' start losing its "streetability", especially if you are planning on taking extended trips with it.

You need to consider what your normal usage will be and what expectations you want out of the vette (i.e. performance, handling, sound, fuel economy, comfort, etc..). More specifics and details help us help you with future upgrades.

 

1A,

I meant I have never really DRIVEN my car, or any high performance (that's a relative term of course!) car for that matter. So I really have no baseline experience to draw from.

So here's what I'm after..

-Decent idle..I dont want to have to keep my foot on the pedal to get 'er to run...

-Ability to drive around town without sprinting from light to light...

-Smooth linear acceleration...

-Strong noticeable torque during low and mid rev acceleration...

-Ability to effortlessly accelerate and pass from 50-60 up thru 80-90...I really dont see myself driving this 40 yr old car much faster than that!!

-"Decent" gas mileage...high teens+ which is why I went with the O/D transmission and kept the 3.08....

All the other "creature comforts" I have pretty well covered..

Thanks!!!

Rob

 

Just curious but why did you go with such a high stall converter? With 3.08's and 2800 stall you must have to really gas her up to get moving eh?

Want a little extra performance uncap those STS's, that's what I did with mine.

 

I think its 2400. I went with the rec of the tranny shop, I dont think they would have recommended a 2800. It was a couple of years ago, so will have to check the paperwork...

Rob

 

Just curious, but did they say why they recommended a 2400 stall? I know you only drove it around the block so far, but what do you think of it? How much throttle is it taking to get it moving with 3.08's?

 

I really dont remember why the 2400. I'm thinking they MAY have called the converter supplier (I really am guessing here) and gave them my engine/rear specifics. I know they researched it through some channels. Also, the owner of the shop has a Chevelle similar to my setup, and he runs a 2400 and recommended it. I was pretty much clueless to the whole "stall" thing.

The VERY short drive yesterday didnt tell me too much. I was basically checking out braking, tracking, steering center, etc. so wasnt paying too much attention to rpms/movement.

FWIW, my ZZ4 was always planned to be an interim motor. I got a screaming deal on it from a kid who was getting out of the army and had to get rid of it (brand new, never uncrated).

My goal is a "streetable" (here we go again) 450hp/450tq +/- good-mannered motor. I also have had plans to eventually go to a lower rear gearing, bumping down a couple of notches for better acceleration and to get more into the power band of the motor.

Now that I just bought a C6, the 72 is taking on more of a FUN role, and gas mileage is definitely slipping down the "important to have" list!! Maybe a ZZ502 is on the horizon! (just kidding...probably)

Thanks for the discussion!!
Rob

 

I'd probably drive it for a while to get a feel for it and see how you like it, then start looking for what upgrades you feel it needs and would add to a better driving experience.

This morning I got a video response on my youtube site, thought I'd share it:

Not sure about that wing though...

 

One might see this and say its not streetable,but it is ,starts and runs like a stocker.Looks are deceiving.

 

im kinda wishin i would have opted for some more mild manners... i have a 750hp 496 with cnc air flow research heads and a 950cfm carb.... 7 miles to a gallon when i baby it.. drives like its on ice coverd with vasoline on the street... sound like a locomotive running over rocks. and get this my engine builder talked me into a milder cam than i bought. but its a toy not a daily driver... i think a zz383 from gm performance is the middle of the road.....perfect for performance .. perfect for the street.... Rich....

 

oh yea billy thats a perfect vette!!!!

 

My .02
My 79 is a 406 powered cruiser,10+compression starts on the first try without pumping the gas,does not overheat,idles at 700 in gear with the air on and runs 12.80 in the 1/4 mile.Appx 460 hp/475 tq
Aluminum heads,hyd roller cam and a 2004r overdrive with a 2200 converter.I can drive it daily or to Cincinatti(125 miles) with NO issues or need to carry a tool box.......

 

I know of many C2/3 Vettes that WILL go around turns really well but, they aren't "Streetable" in my book.

Level of motor tuning, suspension tuning, what an idividual would put up with on a normal bassis are factors of streetability.

My wife did a dailey 25 mile commute for about 2 weeks in my solid roller cammed 72 LT-1 Vette with 4.56 gears. The traffic was stop n go so, she really liked having the 4.56 gears, that's why I love her so much! My kind of gal

 

As long as you can keep it cool there all streetable to me...or no radiator then its obviously not streetable...

 

Here's my idea of streetable, I started out with a base 72 coupe, added an 8.5 cr 468 motor with oval port heads, mild cam, and a twin turbo setup. For the trans, I installed a 4L80E with an 1800 stall lockup converter and 3.08 rear gears. Docile motor with lots of torque off the bottom, gets decent mileage, tachs 2200 at 80 mph, easy to start when its warmed up. My goal is to build a nice cruiser as I like go on those occasional long drives but when you want to go fast, it does that too. 800 hp under the hood gives it the power to blow the tires off at anything under 65-70ish mph but it putts around like a stocker otherwise.

 

My first Vette was a 67 427 Big block car, with a huge amount of engine work done before I bought it. It was almost rediculous. It had a zoom 3 finger clutch which was touchy, but it had way too much torque for the street. I probably could have regeared it or changed the clutch, but got a good offer and sold it and kept my 10th ann Trans Am at the time. To me streetability is a car that can have manners until you want it not too.