What will it run with new convertor? Guess

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TXDart

TXDart

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Here is the build:
1974 Dart SE weighs 3575lb with me in it.
318 .030 over
zero decked
Keith Black KB167-030
Eagle I-beam rods
XE275HL 231/237 duration at 0.050, and 0.525-inch lift, on a 110 degree
340 forged crank
Hughes Iron ram heads 2.02/1.625 (engine quest)
ProComp Air Gap
FBO ignition box
FBO custom curved distributor for my build
Proform 67212 650 cfm Mechanical Secondary Carb DP
COMP Cams Ultra Pro Magnum Rocker Arms 1.52 RATIO
Built 727
8 3/4 auburn 3.55


w/stock 11" stall convertor (1800) and demon 650

DIAL 14.71
R/T .422
60" 2196
330 6.225
1/8 9.522
MPH 75.20
1000 12.378

1/4 14.819
MPH 91.96

Switch to ProForm 650:

DIAL 0.00
R/T .5678
60" 2.174
330 6.0981
1/8 9.3505
MPH 75.77
1000 12.1696
1/4 14.5611
MPH 94.51

What will it run with new convertor? Dynamic 9 1/2 3600 stall convertor....
Guess my 60', my 1/8 mile and 1/4 mile time....MPH too.
Hey my reaction time has been off on my best runs...
With the old convertor my car would not even spin the 275/50/15 M/T Drag radials but a half a tire.....
Guess what I will run and I will post it this Friday Or Saturday when I get to the track.
LET SEE WHO IS CLOSEST TO MY TIME SLIPS
Use this format:
60"
330
1/8
MPH
1000
1/4
MPH
 
It should run, or at least ET better, but that MPH shows one really weak motor......Id look at my tune and figure out why its running so poor.
 
60' foot 1.8-1.9...
330'- 5.60-5.80
1/8th:8.60-8.70
1/4: 13.80-13.90 @99-102 trap speed....
Curious how the chassis reacts, to the converter change.
 
I wouldnt call that teener "a really weak motor".
Hes running very close to oem 70 Swinger 340 numbers, which were low14s at a tic under 100mph. And they were 3310 race weight. And hes doing it with 22 cubes less,3.55s and 265 extra lbs! Common,that teener is moving!
That 3600TC will really help get it off the line. But you already know that the 3.55s are killing the top-end charge.Your car is moving away from DD and into Brawler with that TC, so, you might as well throw some gears at it.
My math puts you into 4.30s at the least. These will put you at;
Mph= {Rpm/(1+TC slip) x tc}/(1056 x R1 xR2)............(6350/ 1.04 x 82)/(1056 x 4.30 x 1)=110
Cant promise you a 110mph, just that 6350 will get you 110 with 82 inch tires and 4% TC slip. But if you work the math; 5700rpm =98.75mph(with those 4.30s). Now thats do-able! That cam will really be earning its keep at 5700.
How quick you get there,well, that depends on how much money you stick into the suspension.
 
I am too lazy to guess all the specifics, but I will guess 14 teens.
 
OH forgot to mention this is a street car,cheapo summit headers with Jeg's 2 1/2 inch exhaust out the back with flow master knock offs.



Abodybomber said:
Curious how the chassis reacts, to the converter change.
Click to expand...
Got frame rail connectors and running with sway bar attach this weekend will remove next time out...doing one thing at a time

AJ/FormS said:
I wouldnt call that teener "a really weak motor".
Hes running very close to oem 70 Swinger 340 numbers. And they were 3310 race weight. And hes doing it with 3.55s! Common. That teener is moving.
That 3600 will really help get it off the line. But you already know that the 3.55s are killing the top-end charge.Your car is moving away from DD and into Brawler with that TC, so, you might as well throw some gears at it. My math puts you into 4.30s at the least. These will put you at;
Mph= {Rpm/(1+TC slip) x tc}/(1056 x R1 xR2)............(6350/ 1.04 x 82)/(1056 x 4.30 x 1)=110
Click to expand...
I got 3.91 that will go in it soon,do have some 4.10 but the highway driving would be out !
 
"Got frame rail connectors and running with sway bar attach this weekend will remove next time out...doing one thing at a time."
That's a good start... If it starts having traction issues, (that's a good thing here, more firepower off the line) highly recommend a video of the car off the line,possibly the full pass.
 
The motor is doing the best it can with all that weight. Maybe just for a weekend test - take 4 hours and see how much you can get of the car you could just easley bolt back on? Bumpers, hood, back seat, spare tire, jack?
Something to try that will only cost time.
 
Abodybomber said:
"Got frame rail connectors and running with sway bar attach this weekend will remove next time out...doing one thing at a time."
That's a good start... If it starts having traction issues, (that's a good thing here, more firepower off the line) highly recommend a video of the car off the line,possibly the full pass.
Click to expand...
I try and get a video and I have driven it .It spins now and bites pretty quick.

j par said:
The motor is doing the best it can with all that weight. Maybe just for a weekend test - take 4 hours and see how much you can get of the car you could just easley bolt back on? Bumpers, hood, back seat, spare tire, jack?
Something to try that will only cost time.
Click to expand...
The weight is with the back seat,spare and jack out of the car.I did rip the headliner and insulation out yesterday.( another 2-3 lb loss)

AJ/FormS said:
Hi-way driving is out with the 3600TC anyway
Click to expand...
Ouch the truth hurts....
The 318 is going to eventually go in my 66 Dart which is way lighter.
 
4.30s in a 8.75 Drum to drum, and matching driveshaft. Complete swap-outs are faster than chunks, and less messy.

Ok since you're dreaming big, go with the 4.10s that you already have. To me it seems hardly worth it to put the 3.91s in if you already have 4.10s.
But I would swap/sell both of those and start with 4.30s. They will take you from 5700@99 to 6300/110. Thats at least 3 cam sizes in a teener,@3575#, maybe 4.And they will be just right in the 66 as well.
If you still wanna take to the hi-way, you will need an od trans and less TC.With the o/d and 4.30s, you could get away with less TC, for a dual purpose vehicle.
Or get a 2nd car.........
 
AJ/FormS said:
4.30s in a 8.75 Drum to drum, and matching driveshaft. Complete swap-outs are faster than chunks, and less messy.
Click to expand...
In the Future,I actually taking the whole 8.75 w/3.55 out of this Dart and putting in my 66 Dart and building another one, I got housings and sure grip chunks just need 4.5 pattern axles.
 
AJ/FormS said:
Hi-way driving is out with the 3600TC anyway.
Nice car. I had a 73 mordoorteener. I thought it was a tank. At 3575, yours is about half what mine weighed.lol
Click to expand...

Maybe with a 1980's converter. The new ones like this one may run less rpm than most expect on the highway. I know of many that were running an old school 2800 and installed a 3600-3900 9.5" converter and highway rpm went down because it's more efficient on cruise. Still has the nuts when romped on. New converters can be the best of both worlds.

The car has 60' issues. It's roughly .2 slow right now for the 1/4 MPH. If the 60' comes around the car could pick up as much as .75 second or better. It could go as good as 13.00 or better when sorted out as it sits. The converter should pick it up in the front half. It runs pretty good on the back half.

If it got to the 1.8's or better in 60's a high 13 is capable. Then it's off to wittle it down. Timing, jetting, squirters all that fun stuff. Get the front end as loose as possible to transfer weight. Abodybomber has a good set of numbers to hope for in this case. If you get over 100 MPH, that's a 13.20 or better in a solid chassis.
 
re post#12.............I see

re post#13..............I see........... But ; they're still slipping, making heat outta gas dollars, and possibly pumping that heat into the cooling system, and wearing out the engine.

CB, I know you're sharp. But how far do you want to drive a teener Dart with 3.55s and a 3600TC, at highway speeds, in wide-open-country, Texas, In the summer And Im guessing no A/C( I mean he took the headliner out for 3 pounds! So the A/C must be long gone)

Not trying to pick a fight. But just how far has technology come?
I have almost always been a stick man.Never had more than 80's convertors.
Yeah that old stuff was a wee bit , um, inefficient, but it did what it was supposed to, under full power.
 
I will guess your 60' to be high 1.8's and your E.T. to be 13.7's at 99 mph. Keep us posted!!!!
 
^^^ I agree with 318willrun ? (That felt weird?) I still think some weight loss would help us (again weird?!)
LOL
 
I've been disappointed with converter swaps before but I'm guessing you will pick up about half a second. The change will likely require some changes to your tune I bet another 2 tenths after that is ironed out. It probably won't help the mph much but the first half is where you will get most of it.
 
What do you have for a fuel system?
Do you know how much fuel pressure you have thru the traps?
Needs to be around 6LBS.
This could be why the MPH is down.
Not enough fuel pressure isn't always identified by stumbles or high speed engine miss.
An engine could just lay over.

The convertor will for sure give the bottom end a boost, if the tires hold.

I'm thinking 13.90's & 60ft in the 2.00 range.
 
Something isn't right that car should be quicker...have a friend with a '70 dart "smog motor" 318 stock bottom-end .477 cam j heads 1.88/1.60 valves weiand dual-plane intake edelbrock 600 carb headers dual exhaust..has been 13.75
 
stroked340 said:
Something isn't right that car should be quicker...have a friend with a '70 dart "smog motor" 318 stock bottom-end .477 cam j heads 1.88/1.60 valves weiand dual-plane intake edelbrock 600 carb headers dual exhaust..has been 13.75
Click to expand...
You are correct
 
AJ/FormS said:
Hi-way driving is out with the 3600TC anyway.
Click to expand...

Not true. I have the same brand converter as the OP except it's a 5500 stall converter and drive it on the highway frequently when it's driven.

I think you'll pick at AT LEAST 4 tenths with the converter change if not more.
 
stroked340 said:
Something isn't right that car should be quicker...have a friend with a '70 dart "smog motor" 318 stock bottom-end .477 cam j heads 1.88/1.60 valves weiand dual-plane intake edelbrock 600 carb headers dual exhaust..has been 13.75
Click to expand...

I said basically the same thing in post 2, but was told 75 mph trap speed is "moving" for what it is. No point in pointing out I have been 8.90s with a smog 318 and a OPEN 3:23 rear on street tires, in a duster. Oh well, he will pick up if he keeps tuneing on it.
 
Post #5

http://www.forabodiesonly.com/mopar/showthread.php?t=224050

It doesn't take gear and a bunch of other stuff to run in the 12's and high 100's mph with an auto. It takes a good converter and chassis. Post #10

http://www.forabodiesonly.com/mopar/showthread.php?t=154106

I drove all the time with an 8" converter on the street. 28" tire, 3.23-4.56's depending on car. Use a large plate style cooler and go if concerned with heat. Converters are not the mush rings they used to be.

I agree that something is off with the current set up, especially down low. Timing, pump shot, launch method. I'd expect the build to make at least 375hp/400ish tq. Should be good for a mid 12 at high 100's mph even at 3500#.
 
I wasn't very critical of the performance of his 4dr mainly because I'm at 3600 ft ASL and don't get spoiled by low altitude numbers... :D
 
Do you have an A/F meter?

Take some jets with you and I'd jet it down from stock if it has 70-72 F/R. It may be really fat which would hinder the car from accelerating.
 
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