12 Second 340

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bobscuda67

bobscuda67

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Everyone knows what it takes to get a A body 340 car into the high 12's. But what is the least amount of work it would take to get it to run 12's?
I'm talking cast iron heads, stock manifolds, radial tires. A real pump gas all steel street car that's all there.
Back when our car's were new they ran 14.60's stock on bias ply tires. Is there someone here with a 12 second car that fits that description? Tell us how you did it.
 
Like complete with thermoquad, cast intake, etc? Obviously the short block has to be in good shape. Getting some work done to the heads would help.

I'm guessing the key would be chassis (meaning springs and shocks, front swaybar disconnected), 3.91 + gears, MT or Hoosier drag radials, cam, converter, trans brake, two step.

Having 2.5 exhaust from the manifolds back wouldn't hurt, either. You could also disconnect the clutch fan, bump the timing, richen the mix a bit, air the front tires up to unsafe levels, spacer under the carb, etc.

It doesn't take a lot of horsepower to run high 12s, but it does take hook.

Or you could just spray it....
 
this is easily done!

good converter 3000-3500 stall
3.91 rear gear
set of soft DOT tires
throw a solid lift cam in it
performer rpm intake
hp 340 exhaust manifolds
750 carb and your there.

i had this exact setup on a worn out 318 and the car went 13.68 at 105
 
Or you could have gotten the MoPar "Engines" book where they give you every part number for every part to put into your 340 engine, trand, rear, suspention etc... to run the time you select.

These "Tips" have been out for years and years with updates to there "Time zones" your looking to run from 14 seconds down to 8.90 index.

Grab a book!
 
Throw a 4" arm in it, some cam, 4.10's, a true 3k stall, tune up the carb and timing and you'll look stock and probably get there. jmo
 
Cheapest way back in the day was to remove the spare tire,jack and back seat along with anything else that weighed the car down.I know thats a given now-a-days.That is,if I read the OP correctly,running a completely stock car.
 
A good STOCK 68-71 10.5:1 340 will go 12:90s with GOOD rear suspension 4 series gears and slicks. Some of yall are slap stupid crazy.
 
12.00's???

A "TRUE" 390-400hp in a good working chassis with plenty of converter/gear at 3300#

Or smack a stock 340 with a 80-100 shot!
nitrous.gif


Plenty of ways to get there that don't require special parts in relation to heads/intakes.
 
StrokerScamp said:
A good STOCK 68-71 10.5:1 340 will go 12:90s with GOOD rear suspension 4 series gears and slicks. Some of yall are slap stupid crazy.
Click to expand...

Radials are the big variable in his question......I agree with you as i've seen it done too. If he's talkin' like radial T/A's he'll have to run 108-110mph in the quarter to get there and probably with a 2.0 60ft.
And yes sometimes being stupid crazy is fun...lol. I wish i had the coin to play with this idea, probably a dozen different ways to do it. Would be fun to screw around with:D.
 
StrokerScamp said:
A good STOCK 68-71 10.5:1 340 will go 12:90s with GOOD rear suspension 4 series gears and slicks. Some of yall are slap stupid crazy.
Click to expand...

X2

LOL ya gotta love Stroker for his honesty. Back in the day you could move the battery to the trunk and remove the rear clips from the leaf springs to help your slicks get good bite. Real magnesium front runners were also preferred. A trip to the local airport for aviation gas was another little item to help.
 
I owned a 1969 340 Swinger. Auto 3.23 and no Posi. Also had big G78 Goodyear radials. I had fun running down 911's with that car. But on the strip it was no fun. I finally dropped the right rear to 8 lbs and if I was real careful I could peddle it off the line with out turning the right ablaze. You see those old fuelers that smoked the tires all the way down the strip. Well that is what this car looked like on one tire. LOL Anyway. The only mods to that car I did, Was put in a dual point mallory. Inverted the stock air cleaner lid and fattened up the primary side of the AVS Carter. That car on it;s best run ran 14.50.
101 Mph in second gear. So I figure that car with gears/posi and some decent rubber would easily have run in the high 12's. I put that car on a chassis dyno once. 330 HP at the rear wheels. Such an underated mill.
 
I have Larry Shepards book but a lot of the info is dated.
This conversation came up with a freind of mine with a 2010 R/T Challenger.
He was laughing at me because I would like to try to get my car to run
12.90's. He bolted on a supercharger and a KN filter system, disabled the trans limiter and he's run a best of 11.90 with a 2.49 60 foot on radial tires.
He doesn't think 340's run that strong, and it would take a lot of work to get there. It would be fun to play around with and see what it would take.
 
This conversation came up with a freind of mine with a 2010 R/T Challenger.
He was laughing at me because I would like to try to get my car to run
12.90's. He bolted on a supercharger and a KN filter system, disabled the trans limiter and he's run a best of 11.90 with a 2.49 60 foot on radial tires.


Those were the guys i loved to run on the street with my high 12sec. cars. More power than brains.....lol. I'd be gone and they had their cars weezing trying to catch me:D.
Click to expand...
 
bobscuda67 said:
I have Larry Shepards book but a lot of the info is dated.
This conversation came up with a freind of mine with a 2010 R/T Challenger.
He was laughing at me because I would like to try to get my car to run
12.90's. He bolted on a supercharger and a KN filter system, disabled the trans limiter and he's run a best of 11.90 with a 2.49 60 foot on radial tires.
He doesn't think 340's run that strong, and it would take a lot of work to get there. It would be fun to play around with and see what it would take.
Click to expand...

Do like he did...bolt on a supercharger...should be no problem running 12.90s...
 
mopar410 said:
Cheapest way back in the day was to remove the spare tire,jack and back seat along with anything else that weighed the car down.I know thats a given now-a-days.That is,if I read the OP correctly,running a completely stock car.
Click to expand...

This is what (I would have said. Strip the weight from it, go on a diet, run with as little fuel as possible, small lite front tires, heck the list is endless. Every little bit will count. You can get an old Fleetwood into the low fifteens with some creative chopping.
 
From what i'm hearing, it's not that easy.
I'm talking no supercharger, no slicks, no spray, no 4" arm and a full interior. You know, a stock car.
 
They did it back when but now we contend with mickey mouse gasoline which has a lot to do with good times.

I also agree with StrokerScamp on his answer even though he's from Georgia..
 
Hi Bob, For this scenario you'd probably want to start with a 71' Duster 340. It still had reasonable compression and the intake and T/Q carb have the most potential of all. With a carb blueprint, a perfect timing curve and 3.91/4.10 gears i can see mid 13 potential. Then working from there, maybe a little more cam, a little more but not too much converter, if auto, and losing some weight would probably be the next steps. Then maybe a few suspension tweaks. Some form of stickier street tires would be the only way for consistant runs though. It would be a slow trial and error process, but that may sneak up on a 12.90?

P.S. Running downhill with a 50mph tailwind wouldn't hurt either:D.
 
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