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Drivetrain 'slop' Question for Turbo Car

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Test drove a car today and had a few issues/questions that I could use help with.

Drive train is:

Dart 363, turbonetics 82mm ball bearing, Trickflow heads...780@wheel 12psi.

6 speed magnum, Spec(?) single disc clutch, alu. drive shaft, 8.8 with 3.55's L/S.


The engine starts/runs/pulls smooth and has tonsssss of torque at low rpms.


Here is my problem(s):

First, this is a 'street car', no cage, full interior, frame connectors, damn thing looks stock...besides being lowered and shiny wheels.

Never driven a car this powerful before so don't go blaming my driving 100%. Starting off in

1st, it is a little testy...that I think is me not being use to the car. Once you get going,

like foot off clutch, you have to go or slip the clutch to drive slow...parking lot/gas station/

my long driveway. It will shutter badly, not engine sputter, drive line 'slop/shuttering'.

Driving in traffic would be a nightmare. Once you get going it will shutter going down the road, worst in 1-4 than cruising on highway, but it is still noticeable. By shuttering I mean if you

are going 30-40(2-3000rpm) around town and are just barely touching the gas to stay at your speed, it was not happy unless you gave it some gas to go. It took nothing to get it to go, but we were trying to stay with traffic. If you let of the gas, for a lite/stop sign and try to decel. in

gear, by 2300 rpm it would shutter until you downshift/coast to a stop.

Don't get me wrong, I did not think I would be like driving a Focus, but was not happy as to how

on/off it was. It was great on a few on ramps merging with traffic, pulled like a F-ing train,

even at partial throttle(low rpm, less than 3500). 5th gear 2000-2300 65mph, give it a little gas(very little) she goes zero hesitation. Because of this, it seems to be a driveline issue.


I really want/need to have a car that is more everyday friendly and hope this is something that

if fixable. If this was a car you just occasionally drove to the track(whatever racing you choose)it would still be a pita.

Any ideas/experiences/thoughts would be much appreciated.




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Looks like you're thinking abut buying this car so don't know much about how it was put together.  What does the builder say about these issues?  Could be something as simple as weak motor and/or transmission mounts.


Sounds like a poor job on the swap.  Something is loose or mis-aligned or out of balance.  Stuttering (shaking?) on deceleration is a sign, since it has nothing to do with peak horsepower.



Forgot to say - this isn't a Ford issue, it's more of a general drivetrain or swap issue.  You might repost in a different forum to get more looks.

Edited by NewZed
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I don't know it from A to B, did not build it. Original owner 55000 mile car. Various engine combos, this 'final'

drivetrain is end result of years of his work. It has about 6000 miles on. Not a poor swap, nothing is loose/broken.

Car is spotless, original paint, interior all in 9/10 condition. I don't think is scaming me, he had plenty of

opportunities to off load the car to make a quick buck. He actually is waiting for the right buyer for his baby.

Was not sure about the placement of the topic, put it here because of the parts involved. Thought it would be more

likely a V8 swap thing than with a old/stock combo.

He did say it will be smoother with driving experience, and the shuttering was mainly the slop in the driveline when not under load. I agree with the smooth part on start-off/engagement of a gear. not the decelerating to a stop. Like I said, never driven a car like this and maybe with this hp and a 6 speed it won't drive like a 'normal' car. But if a

different clutch/flywheel combo, a steel drive shaft can be installed, or ????, this car is crazy nice.

If something was loose/broken it would get worse not better with power application/rpm's.



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Here is a easy way to test slack in the driveline and compare it to others.



In general an engine should be smooth, to hold a car at 30 mph still requires a good amount of energy. If the engine has difficulties holding a steady speed, I would check to make sure that the engine is not running lean under light throttle conditions. 

Other thing I would look into, is with a car with that much power, I would suggest getting a progressive throttle. I can tell you that it does make a big difference to be able to drive a car on the street with a progressive style of throttle. 


Good luck. 

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Just sent a message to Holly about a progressive linkage kit, will see what they say. Could not find anything searching web besides custom made stuff. It has a 80mm Holly TB you will find on many Ford SBs.

It sounds like a great idea.

As far as the lean/richness of the engine, not sure how that will effect a decelerating car. The car does have a

real time data log display as well as a A/F meter. Most of my driving was in the 1-2% TPS and had 13-15 to 1 A/F

reading(0 boost). Slightly lean, but whenever you gave any throttle to produce boost, instantly went to 10-12 to 1.


Crusing highway, 65 mph, 5th gear, 2200rpm, 1 TPS, 13-15 to 1...mainly in the 13 to 14 range. Honestly did not notice

what it said on a pure coasting situation.


If anybody has a combo that is even slightly similar to this....if you are in any gear at 3000rpm and let of the

throttle, will your car smoothly decelerate to basically a idle situation without and shuttering/bucking?

Other situation would be once you get the going in first gear will the car putter along on it own(torque) without issue?

My dump truck with a manual and a V10 could be driven at less than a crawl in first gear, just its own torque. Granted it had a rather short 1st gear...but the Tremec's 1st is not a crazy high ratio(don't know specifically what it is).

Just going by how it feels.


Thanks again,


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I received a reply from Holly tech line....big 'no' on any type of progressive throttle linkage for a single blade TB.

They suggested modifying the pedal ratio or extending the point of attachment on the TB itself, both thing I had thought of...just hoping for a bolt-in kit. This seems like a good idea as far as making the car easier to get moving from a

stand still, don't see a huge help in drivability.

Still would appreciate any feed back from anybody with their drivability experiences. I really don't see where ahigh powered car would act any different than a 'normal' car would in a zero throttle/coasting situation.

Make fun of me all you want, just need a answer...this car is way to nice to pass-up.



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You sound like a guy who's got stars in his eyes for high horsepower,  The car sounds like someone's project that is not "done" and may not even be well-designed and executed.  I wish I could find a GIF for Dirty Harry's "do you feel lucky" line.  


Shuddering at take-off is usually a clutch engagement problem.  Maybe it's slipped a few too many times under all that power.  Or the 1st  gear ratio is too tall for the diff ratio.  Lots of questions.  Just buy it and start working on it.  Who wants a car that's done anyway.

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Have no stars for HP, actually asked the guy to tune it down. Would rather have a lot less power and have a easy car to drive. It makes 780 rwhp now and has made 840,potential for 1000 with VP. On the highway she is a kitten.

Car is completely done and the nicest original looking car I have ever seen.

The take-off issue is my lack of time driving the car, the shuttering questions I have asked are in previous posts

Not sure of the Tremec's first gear ratio, but it does not feel crazy tall and the rear is 3.55's.

The reasons for buying a car like this is to spend about 1/3 the cost to build a similar car.



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With that much power, $20 says it is too wild of a cam for easy street driving. A wild cam gives you power pulses at low rpm that are masked at higher rpm. My cam is stock LS2-smooth as silk, but I'm leaving 50-100hp on the table that a cam/intake swap could give me. But I can idle in traffic and leave stop signs in third gear, smooth as silk, no problems. Race tuners and dyno tuners tune around wide open throttle for max torque and hp, driveability be damned.

Edited by RebekahsZ
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  • 2 months later...

Well it has been a few weeks....changed a few things and made some progress. Off topic, but some might be

interested. Set-up again is a 363 dart, mild cam, cnc'd heads,82mm y2k turbonetics and a tremec magnum.

Came with dual 3"tail pipes with Dynomax welded mufflers. Sound was not to my liking....removed mufflers,

kept tail pipes.

Sounded crazy loud when first started(in open garage). Actually not that bad on the road, even with windows down on highway. Has a great bumpy sound out the back at idle. This had zero effect on drivability, neighbors

might not approve early morning drives.


One thing that has made a decent difference is....as AkRev(and others have suggested) fatten up the part

throttle tune. Much easier to drive, still shutters on decel a bit....will try one more adjustment to idle

fuel curve to see if that helps. Having a real time A/F gauge is a must. Might be changing the aluminum

flywheel to a billet steel piece if it still shuttering.


By no means a DD car, but getting more tolerable.



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