How does an engine make a car unstreetable?

65ShelbyClone said:

My old '65 notchback had a mild 289, 4-speed, and 3.50 T-lok, but it was scary in the wet. I can only imagine what the '68 will be like in the rain with 75hp+ more.

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My moms Astro Van is scary in the rain, that doesnt make it unstreetable

Just scary in the rain, or scary anyway?

65ShelbyClone said:

Just scary in the rain, or scary anyway?

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well just scary in the rain, the 3" drop doesnt help

allcarfan said:

1320...who in GA can build that engine? Just curious.

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Steve Petty, he is teamed up with Tim Lynch, they run big blocks now, but his last SBF with twins was making right about that.

chepsk8 said:

Back to the question posed before, the 289 Cobras actually ran faster lap times that the 427's! That's why they never got the same results or glory of the 289's. Had to do with better corner speeds, speed of entry, and all that great road racing stuff!

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Thats precisely why Mini Coopers kept up ith jag E-Types on road courses back in the day. It's all about balance.

To me the main parameter of streetability is - How easy is it to drive slowly? As engines become more powerful they tend to act like on/off switches. You lose low-speed torque, which is necessary for slow driving, to gain the maximum power. Fun cars are built for torque. Power, a reasonable amount anyway, comes as a result of the torquier motor.

Secondly I think uncontrollable wheelspin is the next factor, however it is usually a byproduct of factor 1.

Thirdly reliability and fuel economy.

Too many variables for me. Streetable can mean so many things.

I'm going to be yanking my 342 in the next few days and having bullit build a 14:1 motor for it, and yes I will drive it on the street. Except it will be running race gas and its just for fun here and there. (I will be racing it also. )

You can make almost anything streetable but it just depends on how "affordable" it is. Mine will probably drink down 112 like its going out of style, but for the few miles I put on it its worth the shaking of my walls and the smile on my face when I light that baby up. Just like when the 6-71 was on it with the mild engine below it. Ran great in town, and was a blast.

If things are done right and corners aren't cut they are going to be pretty damn reliable on the street cause you can never push them much anyways. Its when your doing lots of passes down the strip with them that the wear really comes into play.


If its a daily driver, then all bets off. If its a weekend cruiser, then why the heck not IMO.

Max Power said:

Thats precisely why Mini Coopers kept up ith jag E-Types on road courses back in the day. It's all about balance.

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balance in a race car is important.

as to what streetable is;

1: starts up reasonably easily on a cold morning

2: doesnt overheat in summer traffic in arizona while running the a/c

3: idles well in all conditions

4: is reliable enough to drive everyday with little fear of break down

5: turns in reasonable fuel economy, imo at least 15 city 20 hwy depending on the engine and the car. it is hard to get a 79 lincoln towncar to get 15mpg city

6: handles all driving conditions well overall.

You want to see unstreetable?

Here is unstreetable:

http://www.nelsonracingengines.com/videos/turbo/BUTCHINHIGH.wmv

notice he says "that was only half throttlr"

I bet he has another daily driver

I'm building a 408 (if I ever get my block back from the machine shop) and I expect it to have good hp and streetability. The CR should be around 9.6 to 1. I just ordered some AFR 185 heads. I haven't decided for sure on a cam yet but I know it won't be to radicle. My machinist tried to talk me into some Vic Jr's but I didn't want to compromise my streetability. They might have been OK but his definition of streetability and mine might be two different things since he is into drag racing.

a 408 can handle the larger ports and valves of the victor jr heads. just run the cam you want to use for the street, and remember that torque is king.

408 stroker

I jst completed a 408 stroker for my 67 fastback......we went all out and used Eagle bottom and AFR heads etc..................heres some of the good and the bad.
Bad...
*you get significant exhaust gasses from the tailpipes (result of the cam mostly)
*this engine does not produce enough vacuum to run the brakes well (around town)....you need to install an extra canister to get a 2nd pump or the brakes go flat on you.
*rough idle is fun at first but becomes a bit of a strech on the nerves after an hour or 2 of city driving
*a 408 should have 3" exhaust to reach efficiency and this engine is loud.
this engine also runs hot, hot, hot.....most guys use an aluminum rad....I had a 4 row copper rad. built and a really good (not a cheap one) mechanical fan and it cools really well...even idling in traffic for 15 minutes.
*lots and lots of heat coming into the cab....you need to insulate the floor boards and front pan as well as ceramic coated headers are a must.
*this 351 block is higher and a bit wider than your 289 and requires small exaust fabrication and the use of a low profile intake (or you won't get the hood closed)!!!!!
The good.....the torque on this engine is wild....I got about 500 hp out of this engine with the AFR heads and 520#'s of torque
you're gonna need bigger tires
*its better on gas than my 289 was....runs down the highway effortlessly.
*match your cam, torque convertor and intake all to come on at about 1500-2000 rpms and you will have an amazing street machine that rolls along well on the highway. Use the best parts available to you and you won't have reliability issues.....plan, plan and more planning. Also put in new motor mounts...you'll need them.
I used a March serpentine system.....expensive but solved the issues of mounting for the p/s and alternator.
Don't be fooled....switching from the 289 to a 351 block is not as simple as some will tell you.....it will fit right in and bolt right up but theres a lot of things that need to be changed and fiddled with. Do it right the first time and you won't need a flatdeck to bring you home.
It will be a couple of thousand dollars extra just to do the switch over after the engine is built (if you do the work yourself)....believe it.
Your car will be a completely different car with this engine....good luck.

Sweeet Ride said:

I jst completed a 408 stroker for my 67 fastback......we went all out and used Eagle bottom and AFR heads etc..................

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Just out of curiosity, what AFR heads and what are the specs on your cam?