Why am I so slow

[71swing]

I own a 71 dodge dart swinger. Just got done building from the ground up.
currently running a 340 with
edelbrock alum. heads
edelbrock airgap manifold
mopar performance cam
demon 750 carb
TTi 1-3/4 longtube headers
727 torqflite with b&m 2000 stall
8 3/4 rear with 4:30 gears
complete dynomax exhaust catback system

But I took it to the track for the first time and could only muster a 9.6 in the 1/8th mile. Doesn't this seem alittle slow to anybody else. The car it's self feels strong. but the timeslips say eitherwise. Please help very imbaressed with a 9.6 timeslip.

 

[rumblefish360]

I do not know how to change 1/8 to 1/4 times. But I have noticed that 1/8 mile runners use a higher gear ratio.
What MP cam do you have in there? It may not match the stall.
What is done to the rear suspention of the car? What tires.
The one thing I have learned about racing at the track or in the street (Low powered cars mostly) is that the first one to 100 mph is a better bet to be the winner at the line. (1/4 mile)
The thing with drag racing a car besides the power the engine makes is the weight it moves. Not just running down the track but also in weight transfer and how fast it can get off the line effectivly.
RPM launch is critical as well.

 

[OldVart]

If my math is correct, I believe that should work out to an almost flat 15.00 sec. 1/4 mile. There is definitely something wrong, you should be running a LOT quicker than that with your setup. What was your MPH and 60' time? What are the specs on your cam? Rumble is right, I don't think your cam and converter are matched up correctly. Are you getting a lot of tire spin off the line? What do you have for a rear suspension setup? Tires? Give us all the info and I'm sure we can get you a quicker timeslip that the last one.

 

[sefus]

Lots of carb on that little 340 too. but a 2k stall seems real low nomatter what cam and tire size you've got. Agree with getting the rest of the specs and track data first, then we can diagnose.

 

[Oldschool]

Could be any number of things, but the converter and whether or not you are spinning the tires or hooking up looks like the first places to start looking. Also, here is 1/8 mile to 1/4 mile conversion table. It's not perfect, but it will get you pretty close. Just scroll down the site a little..... Oldschool

http://www.eldiabloblanco.com/calculator.htm

 

[halfaed]

With those heads, that carb might be a little to big but just barely. I run the 360-j heads on my 340 4 speed with a 650 holley BP carb. in my dart. In the 1/4 and I'm running 13.148 and in the 1/8 i'm at 8.33. and my 60' is 1.71. You need a way better stall also. That is why I like my 4 speed! REV AND DUMP!!!!!!

 

[7172 duster]

we ran the duster 5 years ago with a 360 J heads and a b@m streetfighter converter with 242 gears which means we ran the 1/8 in 1st gear. 9.25 with a 2.25 60 ft. It kind of sounds like there are some timing issues ign. or cam.

 

[340mopar]

Why are you running a cat-back system? Are you running catalytic converters?

 

[71swing]

Search high and low threw all my stuff on the car could'nt find the specs on the cam,but when i installed i do remember the 112 degree centerline. mopar performace selected the came for me. I realize that my stall maybe low but, I dont think that is the real problem. I would think the car would be around 8.5sec 1/8th or low thirteens in the 1/4. I just dont think the converter would hurt me that bad on the timeslip. I also run with the headers open at the track. Will return to the track soon. what I think it may be is my motor is 12:1, may not have agreed with the pump gas, will try 114 leaded. Runnin nitto 555 streets on back, also there was a little wheels spin but still dont think there was much to kill my time that bad, I have a lot less money in my much heavier conv5.0 mustang and it will run 8.7 or 13's all day.
r/t .018 power braking to put load on suspension
60' 2.262 not the greatest
330' 6.301 not sure if this is good or not
1/8th 9.600 embarassing
mph 73.78
also runnin 37* total timing @ 2000rpm. what do you guys run on timing.

 

[340mopar]

I would kick your timing back to 34* total. with the compression you have you shouldn't have any trouble firing the fuel and with the pump gas you are asking for detonation. After reading other threads about MP cams being ground way off, if you did not degree your cam I would open up your motor and do that. I believe this is were you are leaving your HP on the table.

 

[GoodysGotaCuda]

something is definately not right. My 318 ran a 9.230 at 3600 ft elevation. Other guys have pretty much covered what i would suggest. being the converter and such. I've seen, and heard converter swaps taking up to a half a second off e/ts. It IS important. Your whole combo needs to work together to get the most out of it..which is why my combo, which is so basic, seems to run pretty well..That converter is definately not helping..And why do you have cats?

 

[71swing]

I don't have cats, somebody else said that, I didn't even realize you can buy a system for this old of a car to include cats. I did degree the cam myself. I going to look into get it dino tuned by sombody more exsperanced with carb's. I'm really knew to the carb seen. Being only 26 really only delt with the EFI scene.

 

[GoodysGotaCuda]

I don't have cats, somebody else said that, I didn't even realize you can buy a system for this old of a car to include cats. I did degree the cam myself. I going to look into get it dino tuned by sombody more exsperanced with carb's. I'm really knew to the carb seen. Being only 26 really only delt with the EFI scene.

I own a 71 dodge dart swinger. Just got done building from the ground up.
currently running a 340 with
edelbrock alum. heads
edelbrock airgap manifold
mopar performance cam
demon 750 carb
TTi 1-3/4 longtube headers
727 torqflite with b&m 2000 stall
8 3/4 rear with 4:30 gears
complete dynomax exhaust catback system

CatBack = Aftermarket exhaust from the catalytic converters back.

So you have a dynomax exhaust, not catback..just clarifying :thumblef:

As far as the carb a ton of things can come into play being new...and running a, what i would consider a high performance carb. I myself, being only 18 and not tooooo much experience under my belt run a 650 edelbrock on mine. Its a daily driver and i dont have any fuss to put up with running it. Holleys and Demons have always been considered for more speed/performance over the carters/edelbrocks. But with that more performance comes much more fine tuning and understanding how it all works. My suggestion would be to do your homework on that carb you have and get it dialed in. There is nothing like finding someone that can help you out hands-on if you know someone with the knowledge.

If not, these guys deal with demons often, and they have a Tuning guide availible for $10 or so if i remember right. They have a pretty good reputation for service/tech/helping out.

http://4secondsflat.com/

-Mike

 

[71swing]

(Catback) to me always ment just from were the headers ended to the back, not that it would necessarily come with catalytic convertors. (cat's optional)

I have a 750 demon with machanical secondaries and it come with tuning instrucstion, but you could have all the instruction in the world and it wouldn't madder, exsperance wins hands down. And I just dont have it, So now that is what Im working on. My own experances, and with the help of this site I hope it to be easier learning.

Thanks guys for all the input. I will take it all in, and acess my problems. Will get back to you when I get it figured out. I will curtenlly let you know what the problem was, so that maybe it can help sombody else.

 

[GoodysGotaCuda]

(Catback) to me always ment just from were the headers ended to the back, not that it would necessarily come with catalytic convertors. (cat's optional)

Flowmaster 'Cat-Back' Exhaust Kit

That kit starts at the back of the cats, to the mufflers, to the tailpipes. never hooks to what is just coming off the motor. Cat of course, is short for catalytic converter(s) . So short for 'from the cats back' would be cat-back...ANYWAY, sorry thats off topic. lol

Definately experience will take reading a book over at any point. But still reading all you can certainly can't hurt a bit. Another site you can check out is Moparts.com. They have a race forum, not saying they are any better than here...or annyyythinngg like that, just another source you can post your questions on and get a couple more opinions....You have plenty of motor left, just gotta figure out how to get the power to the ground and it dialed in. :thumblef:

 

[halfaed]

I think your problem has everything to do with your Converter and carb! Last year the best I could do was 14.12. and that was because I couldn't nail it off of the line. I also had 3.23 gears with 24" tires on 14" wheels out back with a holley 750VS carb. Fast forward to now, holley 650DP, with my car minitubed and stuff to fit some meat under it and 3.91s with 27" tires. Now it 60's at 1.71. All because of how it takes off, now it runs low 13s all day. Yes it makes a big difference about what RPM you leave the line at!!!!!!!

What kind of tires are you running?
One more thing, don't waist your money on the dyno, got to the track and make some new friends that don't have fuel injection. Then ask them to share some knowledge with you. Another good thing to know or learn about is, how to read your plugs.

Good luck.

 

[71swing]

I run 245 nitto 555's, but will be buying 9" slicks as soon as possible, I'ts just my luck that the slicks off my mustang don't fit the wheelwell of the dart without tubing. But don't want to tub,the car is more show than go. I just want it to run like it should. My combo should be making enough power to get me into the low 13's.

 

[71swing]

I looked up cams specs, I believe I installed a p5007696 It was newest cam offered by mopar at the time of purchase. 292/292dur 508/508 lift 2800-6200 prm range with what they called less/o lap for better diveablity.

Anybody familular with this cam, is it okay with my combo.

 

[halfaed]

With that cam you need more stall in that thing!

 

[rumblefish360]

Hell ya! 200 is a step above stock. Your not getting a energy release with that converter.

 

[MidTexCuda]

Your carb is on the big side. Im sure you will fair better with a bigger stall but try barrowing a 650 first. And toy with the timing. See what that does I would also stay with the pump gas if you have no detonation issues. Race gas will kill performance if you don't have the compresion. And if your running that car on pump gas now with no detonation and 37 degrees of timing you might not have 12to1. Getting a car to perform well is all about ballance. No matter how big or small your combo is.

 

[73dart360]

i run a 360 with almost the same set up ,my motor sounded great but hesitated off the line -i put a new TCI super street fighter 10" converter it made a huge difference,i also had it dynoed tuned -before the tune up -the base line dyno was 256 hp to rear wheel and 365 ft lb torque -after timing set and different jets 272 RWHP and 403 Ft torque

 

[Dodgenut64]

750 is a bit big. i made a jump like this with my 70 dart i had. 340 (x heads)with streetable cam,750 dual line holley, peg legg rearend with 904. carb was too big and needed some lower gears. my 5.2 dakota felt faster. dont know what i was thinking with that 750, guess i wasnt thinking.

 

[1968FormulaS340]

I have better 60' times (1.9) on E70-14 tires (very thin).

 

[7172 duster]

These things came out with 850 TQ AND they love it.