Estimated 1/4 mile - 71 Roadrunner 340 4 speed

[340runner]

We used to just turn the timing down, but yes an msd nitrous retard box would be ideal.
I would not bother with any of the electronic c**p ( stuff). Expensive, unreliable, complicated, zero gain. Put that $$$ towards a stroker kit. IMO

Well, why I'm not wanting to just turn it down, is wouldn't it be kind of a dog when not using nitrous? I'd understand for a race application but even if its a heavily favoring race street/strip car it sounds like it would be a big downside

 

[RemCharger]

You would turn it down when you are going to make a nitrous pass.
If you intended to just " drive around on it all the time " just get an auto retard box.

 

[66 Sat]

You can call me a boring old man...but I think you have a great car as it stands and you should maybe re-think your goals.
Why 11 seconds? What prompted that goal? Once you get to 11's you'll want 10's and so on.
I'm in a similar boat to you, but just have a few more years of thinking.
I'm at 14.1 at 99.80 mph. I started at 15.3 at 95 I think.
My goal was always 13.5 at 105, which was road test speeds for a street hemi back in the day, but breaking 13 seconds and 100 mph is the next step.
I'm having as much fun (and frustration) finding these small increments as I would be trying to find whole seconds.
I'm back at the track tonight with the new carburetor I put on over Christmas, very exciting!
My car is a 100% street car. If you're going to run more on the track and not much on the street then it becomes purely a numbers game: more $$$ in = less time down the quarter.
My point is, sometimes it's good to step back and think about what your doing. How often you get to the track vs how often you could drive the car and enjoy it on the street.
If you keep it as a nice street car, and work on small incremental gains you can still take girls out on dates in it etc. Try doing that in an 11 sec car with a cage etc. You won't be able to get in the back seat!

 

[torredcuda]

I started out in the low 14`s and I was a little dissapointed in that ET but with nothing more than swapping carbs and tuning them, changing timing curve and lowering tire pressure I was able to get it down to low 13`s. I agree it`s fun and sometimes frustrating trying to get the same basic combo to run faster - it`s a challenge for sure but rewarding in the end. While I`d love to have an 11 second street car it really is about "how fast do you want to go / how much money do you have" and I just don`t have a lot so I`m fine with what I have. The good thing about bracket racing is it doesn`t matter ho w fast or slow you go - you can still have fun and even win. I`m not one to brag but am pretty proud that I won first with a 727 and then with the four speed.

 

[weedburner]

I recommend starting with your 700hp capable street extreme clutch, which needs to be tamed for your application. Fix that, you will be able to hook the car consistently without breaking parts or bogging the engine. That will also give you the ability to launch on drag radials consistently, no need for two sets of wheels/tires.

My first attempt to tame a clutch like yours was using a hardware store hydraulic screen door closer to control the release of my clutch pedal. Just a simple install between the pedal arm and a slide bracket bolted on the lower lip of the dash. Two adjustments, how fast the pedal returned and where in the pedal's return travel that it became active. Cost me like $20 and a little fab time around 15 years ago. It's the most cost-effective solution there is for bringing an engine and chassis together for an efficient launch. If you can handle basic fabrication, I would do this first before you break anything else, should be within a 16yo gearhead's budget!
Here's a link to pics and info about how I did that first install... https://grannys.tripod.com/hillbillyclutchslipper2a.html

If that DIY off-the-shelf hardware store cylinder is too long for you to work with, I make shorter versions for my ClutchTamer customers. For more info about how the above DIY 'tamer works, go to my website CLUTCHTAMER.COM

Grant

 

[340runner]

You would turn it down when you are going to make a nitrous pass.
If you intended to just " drive around on it all the time " just get an auto retard box.

Ahahhaha see that's what I mean, at the end of the day, I still would like to drive it on the street and have every once in a blue moon or whatever.
Wouldn't be very cool to run out pop the hood and mess with the dizzy now eh? The other side to it though is that can the tires even hold up to a hit of nitrous, which i already know the answer to as a resounding no

 

[340runner]

You can call me a boring old man...but I think you have a great car as it stands and you should maybe re-think your goals.
Why 11 seconds? What prompted that goal? Once you get to 11's you'll want 10's and so on.
I'm in a similar boat to you, but just have a few more years of thinking.
I'm at 14.1 at 99.80 mph. I started at 15.3 at 95 I think.
My goal was always 13.5 at 105, which was road test speeds for a street hemi back in the day, but breaking 13 seconds and 100 mph is the next step.
I'm having as much fun (and frustration) finding these small increments as I would be trying to find whole seconds.
I'm back at the track tonight with the new carburetor I put on over Christmas, very exciting!
My car is a 100% street car. If you're going to run more on the track and not much on the street then it becomes purely a numbers game: more $$$ in = less time down the quarter.
My point is, sometimes it's good to step back and think about what your doing. How often you get to the track vs how often you could drive the car and enjoy it on the street.
If you keep it as a nice street car, and work on small incremental gains you can still take girls out on dates in it etc. Try doing that in an 11 sec car with a cage etc. You won't be able to get in the back seat!

Well, 11s is just a number and I set it as a goal because it doesn't sound as terribly hard to hit as 10s. I'd be happy with any improvements, I just almost feel like its kind of sad on the 1/4 mile time, a lot of modern cars can best it as for 1/4, which i know isnt fair but still, I like to at least back up how my exhaust sounds with good performance . I drove it during summer as a daily without ac, and no wing windows, and i really didn't mind it at all. I'm still at a point in my life where comfort is kind of secondary up to a point to be honest, and as long as it isn't too terribly bad such as a cam large enough to shake all the bolts loose or complete race buckets, I think I'll still enjoy it.

 

[padam]

My suggestion is if you really like drag racing, put a 727 back in it.

 

[340runner]

My suggestion is if you really like drag racing, put a 727 back in it.

Not that much haha, I'll take that concession of having a stick, that's one thing where the fun outweighs the time slip in my opinion, plus there's more of a challenge and skill to it, especially if I ever get into bracket racing

I find a satty or a /6,318 or 360 A body for the right price I don't care if there's a 4 speed in there there will be a 727 and a big inch wedge by the time I'm done with it. Probably little interior either

 

[71Beeper]

Also just wondering, for reference how much does your car weigh and what does it run?
For pure curiosity, you think the 340 since it has a forged bottom end will eat a 100 shot? Sounds like a fun time but I'm getting tires first and if it's a big risk I wouldn't run nitrous

I do not know how much my car weighs. I just finished it in August of last year, ran it for 6 weeks then my head issue happened so I didn't get a chance to weigh it.
Same with running it at the track, that won't happen till I get all the little bugs sorted out and the car is reliable.

I looked at the cam card you provided - it's not too bad. It says the rpm range is 2500 to 6400 rpm - so why are you buzzing your engine to 7 thousand if it runs out of power at 6400? if not earlier depending on how much flow the 'J' heads provide.

To run a 100 horse nitrous in it - your 340 can certainly take it.
I had another buddy with a 1979 Volare with the E58 360 engine, bone stock with the exception of a 340 cam and the 100 horse nitrous.
stock 14" tires on Magnum rims - the nitrous knocked off 1 second from his elapsed time, it went 14.5 without nitrous and 13.5 with it till he crushed the bearings in the rear universal.

As for changing to EFI and Hyperspark - I agree with RemCharger...save your money and stick with what you have or invest in a stroker kit..
EFI conversion is not as easy as you think plus it is costly.
Get some experience working on a carburetor, they are not that difficult.

Kudo's and applause to you young Buck - many guys your age don't bother with these older muscle cars. A lot of the guys here (myself included) started off just like you with a passion for cars.
I never took a single auto class in high school but I read just about every Hot Rod, Car Craft, Popular Hot Rodding and any other car magazine back in the day. I learned by reading the tech articles and taking stuff apart to see how it works.
The experience will come with time. I messed up alot of stuff when I was learning, but don't let that hinder your progress.
And keep asking questions here - as you can see, the rest of us want to help....

 

[340runner]

I do not know how much my car weighs. I just finished it in August of last year, ran it for 6 weeks then my head issue happened so I didn't get a chance to weigh it.
Same with running it at the track, that won't happen till I get all the little bugs sorted out and the car is reliable.

I looked at the cam card you provided - it's not too bad. It says the rpm range is 2500 to 6400 rpm - so why are you buzzing your engine to 7 thousand if it runs out of power at 6400? if not earlier depending on how much flow the 'J' heads provide.

To run a 100 horse nitrous in it - your 340 can certainly take it.
I had another buddy with a 1979 Volare with the E58 360 engine, bone stock with the exception of a 340 cam and the 100 horse nitrous.
stock 14" tires on Magnum rims - the nitrous knocked off 1 second from his elapsed time, it went 14.5 without nitrous and 13.5 with it till he crushed the bearings in the rear universal.

As for changing to EFI and Hyperspark - I agree with RemCharger...save your money and stick with what you have or invest in a stroker kit..
EFI conversion is not as easy as you think plus it is costly.
Get some experience working on a carburetor, they are not that difficult.

Kudo's and applause to you young Buck - many guys your age don't bother with these older muscle cars. A lot of the guys here (myself included) started off just like you with a passion for cars.
I never took a single auto class in high school but I read just about every Hot Rod, Car Craft, Popular Hot Rodding and any other car magazine back in the day. I learned by reading the tech articles and taking stuff apart to see how it works.
The experience will come with time. I messed up alot of stuff when I was learning, but don't let that hinder your progress.
And keep asking questions here - as you can see, the rest of us want to help....

I'm not shifting at 7k, 7k is my please engine don't explode redline for if i miss a shift or anything, my shift is at 6000, but i might test out moving it up a couple hundred rpms, maybe to 6200 or 6300. As for J heads, I don't have them I have speedmaster alu heads which I bet flow better. I'll definitely learn how to work carbs and set timing myself, and I'll invest eventually in a MSD digital 6+, since it seems like the best bang for the buck package out with 2 step, start and nitrous retard. Plus i already have a 6al non-digital I don't want to just turn the dizzy to retard timing, as I like to drive on the street and you never know.

 

[RemCharger]

MSD Ignition 8987 MSD Start and Step Timing Controls | Summit Racing MSD Ignition 8987 MSD Start and Step Timing Controls | Summit Racing

 

[Phantomx]

This isn’t what you asked, but let me lay some real world experience on ya. If you want this to be a hot street car, concentrate on making it a good and fast street driver. Forget about the track, make the car as fast as you like. You have a very cool car, I would suggest not destroying it trying to drag it at the track. The track is harder on your car than the street. If you end up wanting to run at the track, get a run of the mill a body and gut it out and race the **** out of it.

Having had a few cars that I casually drag raced, and a number of 4x4s that I drove on the street and used for rock crawling, I say dual purpose vehicles are a giant compromise that you will never be happy with. Trust me, I’ve built enough stuff and sold it to chase a different thought to know what’s up. A fast and fun street car, and a drag car that can run a certain number are two VERY different things.
Travis..

 

[340runner]

This isn’t what you asked, but let me lay some real world experience on ya. If you want this to be a hot street car, concentrate on making it a good and fast street driver. Forget about the track, make the car as fast as you like. You have a very cool car, I would suggest not destroying it trying to drag it at the track. The track is harder on your car than the street. If you end up wanting to run st the track, get a run of the mill a body and gut it out and race the **** out of it.

Having had a few cars that I casually drag raced, and a number of 4x4s that I drove on the street and used for rock crawling, I say dual purpose vehicles are a giant compromise that you will never be happy with. Trust me, I’ve built enough stuff and sold it to chase a different thought to know what’s up. A fast and fun street car, and a drag car that can run a certain number are two VERY different things.
Travis..

Well, what do you consider as a fast street car, and how does it differ than a race car? I know i will need more power to run the same time as a race car, as I'll have a lot more weight. As saying again with fast street cars... modern vehicles have been able to master driveability while being fast, how do you stack up? I guess this all comes down to what you consider a fast street car

 

[Phantomx]

A fast street car is whatever you want it to be, but you don’t have rules that require certain equipment based on e.t. As long as you can drive it on the street where you live without being hassled, you’re good to go. Yes, modern cars are faster than older muscle era cars, it’s a fact that you must get used to. THERE IS ALWAYS SOMEONE FASTER! If you want to keep up with modern supercharged v8’s, just get one of those and sell off the road runner (or install a late model supercharged engine/trans in it). If you keep the car street instead of building it around track rules, you will use the car more often and enjoy it more. You can have a car that is capable of 10s that you can’t run at a track, but you can drive it on the street every day if you like. Ask around to the old guys who butchered their killer street cars to run at the track and most will say they should have started with a different car to make a track only car. You could have a very quick drag a body for probably half of what you currently have in the road runner. Just offering insight from my 40 years of screwing with cars.
Travis..

 

[340runner]

A fast street car is whatever you want it to be, but you don’t have rules that require certain equipment based on e.t. As long as you can drive it on the street where you live without being hassled, you’re good to go. Yes, modern cars are faster than older muscle era cars, it’s a fact that you must get used to. THERE IS ALWAYS SOMEONE FASTER! If you want to keep up with modern supercharged v8’s, just get one of those and sell off the road runner (or install a late model supercharged engine/trans in it). If you keep the car street instead of building it around track rules, you will use the car more often and enjoy it more. You can have a car that is capable of 10s that you can’t run at a track, but you can drive it on the street every day if you like. Ask around to the old guys who butchered their killer street cars to run at the track and most will say they should have started with a different car to make a track only car. You could have a very quick drag a body for probably half of what you currently have in the road runner. Just offering insight from my 40 years of screwing with cars.
Travis..

Well, that's what I mean by fast street cars, I mean I'm not talking class rules right now otherwise I wouldn't have nitrous, 2 step or drag radials as a question on the table. I'd like something that I can drive on the street and have a lot of fun light to light without being too much of a pain in the *** to climb into, but also not be a 14 second car for the rest of its life, cause I personally wouldn't call that a fast anything. I mean I wouldn't call installing the unit stiffening kits ruining the car, so that's where I'm probably gonna gain the chassis stiffness that I'd otherwise not have from the roll cage. I'm not opposed to a wild motor build that has at least a little streetability or short rear gears, as I'm not taking the thing on a road trip.

 

[Curiousyellow71]

You don't have to put in a new hemi to boost it. We turbocharger a 318 in our 72 satellite and even w 3.23 it was no slouch. Boost is a excellent idea, you keep your drivability and make big power....and today there is gobs of parts and info out there. Just be prepared to work at it! Our car we turboed has a 542 in it now, still has 3.23s.
If you want to drive it naturally aspirated ..don't go deeper then 4.10, unless you do a od of some kind. If you want to go fast w a 4 speed..get a dana 60 in there as soon as possible and look up the Clutch tamer post above! Also protect yourself from a clutch explosion!
Buy as many cubic inches you can and the best heads you can. Don't be afraid of a cam w lift on the street! Nitrous is always a good idea..but remember..it ain't free, and it's addictive. In other words it can be a expensive addiction.Lol
I suggest you learn more about what you have..do a compression check. Split monoleafs and caltracs are a good thing to run on a street car, and buy some adjustable shocks. There are lots of old musclecars racing at our local track sand bagging wo rollbars. They have a good time, but know if they go 2 fast..they get sent home.

 

[Phantomx]

Right, build the car as fast as you like with the comfort you like. There’s nobody telling you that you need a cage or not, just drive the car. There are guys running around in very fast cars that won’t pass tech at a track. I’m saying that track racing is hard on the car because it’s always from a dig which is way more violent and hard on parts than going from a roll. Make it what you want, don’t let track rules force you to butcher your car or make it uncomfortable
Travis..

 

[340runner]

You don't have to put in a new hemi to boost it. We turbocharger a 318 in our 72 satellite and even w 3.23 it was no slouch. Boost is a excellent idea, you keep your drivability and make big power....and today there is gobs of parts and info out there. Just be prepared to work at it! Our car we turboed has a 542 in it now, still has 3.23s.
If you want to drive it naturally aspirated ..don't go deeper then 4.10, unless you do a od of some kind. If you want to go fast w a 4 speed..get a dana 60 in there as soon as possible and look up the Clutch tamer post above! Also protect yourself from a clutch explosion!
Buy as many cubic inches you can and the best heads you can. Don't be afraid of a cam w lift on the street! Nitrous is always a good idea..but remember..it ain't free, and it's addictive. In other words it can be a expensive addiction.Lol
I suggest you learn more about what you have..do a compression check. Split monoleafs and caltracs are a good thing to run on a street car, and buy some adjustable shocks.

Ok, is there any way really to figure out what your final compression ratio is without peeling off the heads? I know about the compression testers that screw into the spark plug hole, but am unsure how the psi would convert into a compression ratio

As for boost, a stroked out 426 small block with a roots blower sounds nice, the fiberglass hood ill get so I don't chop up my original would also save a bit of weight..

Now wondering, why do you say don't go deeper than 4.10s, specifically on an NA build though? Would you say the same if I went with a 28 inch tall tire

The dana 60 was always a thought in the back of my head, also easier to since I can decently easy find limited slip 4.10 versions of the axle from trucks, and I believe I can use my brakes I already have if I'm not wrong

At the point of split monoleafs and caltracs with adjustable shocks, I'm gonna probably be in around 2 to 2 and a quarter grand. Is it really worth it to keep leafs instead of going to 4 link?

 

[340runner]

Right, build the car as fast as you like with the comfort you like. There’s nobody telling you that you need a cage or not, just drive the car. There are guys running around in very fast cars that won’t pass tech at a track. I’m saying that track racing is hard on the car because it’s always from a dig which is way more violent and hard on parts than going from a roll. Make it what you want, don’t let track rules force you to butcher your car or make it uncomfortable
Travis..

Yeah, at the end of the day a verified dragy run is just as worth as a time slip from the drag strip, though some old people may say different. I'm not gonna let the rules hold me back, while running and showing off at a high school night at the dragstrip is fun, the real reason I say the track is because it's a way to actually put numbers and figures to how fast a car is, almost like one would when buying a new sports car