No bottom torque

[phoenix02]

Hey all,

Okay, so I've finally gotten her where I'm comfortable driving (mechanically...) on the freeway with no problems. She still has no bottom torque. I've heard people on here say that their birds and ponies wind up relatively fast to 60, then can eek out 70 and 80. I wind up REAL slow to 60, even when flooring it, but from 50 on up, she runs like a champ. I passed a diesel on my way to work yesterday, looked at the speedo and kinda *ulped* when I realized I was flooring a 40 yr old car with manual drum brakes and non functioning seat belt at about 98mph. She cruises at 80 all day long at 1/3 throttle. Is there any way I can keep this and also get some better acceleration? I was wondering if it's a gearing thing, but if I changed that, I'd get better acceleration, but have to push harder for the top end, right?

200,1940,LOM,C4 all stock.

-Michael

PS- I picked up the performance manual and am trolling e-bay to get a shop manual to complement my '69 Motors. I hope to build up another engine this summer- late model head, 5200 carb, and a different cam. I was thinking 5200 over 2100 for the mileage savings of having a progressive. Is the mileage that different with the 5200 over a conventional 2bbl, or is it negligable?

 

[hasa68mustang]

to me your performance sounds about right... but I could only get mine to 96 in stock form... c4 with the 7" rear... the 0-60 was something like 12 seconds after headers and a 2bbl carb.

 

[Gene Fiore]

Have you tried advancing the timing to 12 degrees?

 

[Anonymous]

What type of cam are you running? it sound pretty typical of a big cam in a standard driveline car where you need to get it revving to produce any torque.

 

[Anonymous]

200,1940,LOM,C4 all stock.

Assuming "LOM" means you have a Load-O-Matic dizzy, you might be getting some performance issues due to using the 1940 Holley (unless it has a spark control valve). Those who know more should correct me if I'm wrong, but based on many other posts I've read here, you won't get proper spark advance unless you switch carbs (to one that has a spark control valve) or switch dizzys (to one that uses manifold vacuum and/or mechanical advance system).

 

[mceachrw]

1940 has a spark control valve

 

[jamyers]

...
I wind up REAL slow to 60, even when flooring it,
...

How slow? 10-13 seconds wouldn't be out of line, but if you're talking 20-60 seconds, then you've definately got an issue.

Things that jump to my mind:
* Carb accelerator pump shot.
* Tranny starting off in high gear.
* Ignition advance way out of line.
* Cam timing chain jumped a tooth or two.

 

[phoenix02]

Okay, I was at the yard today looking for some old seatbelts I could use in the interim until I decide if I'm going to do 3 points or not. I picked up a DSII dizzy and module for $45. I hope that's an OK price. They wanted an extra $12 for the cap and wires, but the cap was thrashed so I decided to get new ones whenever I swap out. I'm hoping switching over might give me some more pep. I also have an Accel coil I can pull off my f500 and a 6a box to wire in I pulled off the MG before I sold it.

I pulled the dizzy of an '81 Fairmont Futura. I'm wondering if the head is the "good one" or if the "good one" is only 78-80. It still had the head for $40. Actually, there where two fairmonts there, both with heads&carbs. I got the module off one and the dizzy of the other.

If I swap on the DSII but leave the 1940 on there for a while, is there any way to take of the SCV and plug the hole or something so that the DSII gets the right vaccum, or do I have to get a carb and swap at the same time? I'd really rather not get another carb, as I plan on going with a 2bbl when I change to the newer head. (I want hardened valve seats and slightly lower compression)

Finally, when I go with the new head, do you think I shoud do a 2100 or a 5200? My thinking is, if I go with the 5200, I can basically have the economy of my 1bbl around town, but be able to open it up and get better performance when need be. Any one with experience with either carb, please give me your input on this.


Thanks,
Michael

PS- Sorry for having two threads, I accidentally posted twice. Is there any way for a moderator to move the posts from the other thread to this one so that it's not two threads?

 

[Mercury Mike]

Well I have driven in Mike's Falcon, and he's right, NO bottom end. It feels like nothing's happening. In my mustang, when I hit it, stock, it goes. =D Mike, did you ever get the adjustable rockers on there?

 

[mustang6]

I'd check timing first, then do a compression test, I'm betting your static compression is low due to either engine wear or a previous head r&r with a thicker modern gasket lowering compression that was not compensated for.

 

[AzCoupe]

How many miles are on the motor? Another suspect, could be the timing chain. If it has a lot of miles on it, it may have a lot of slack or even jumped a tooth. Both would retard the cam/valve timing, resulting in decreased bottom end torque. You might want to pull the cover and check the chain slack.

 

[jamyers]

I'm still thinking carb accelerator pump first, then timing chain.

You can use a DSI or II dizzy with the 1940 carb, just block off the LOM port on the carb and hook the dizzy vacuum line up to the manifold wherever you can. I think there's usually a plugged port on the side below the carb, sometimes used for PCV.

I've got a 5200 staged 2-bbl, and it's pretty nice. Good mileage, and when you stomp it you can feel the secondaries come online nicely. I'm about to pull it and sell it, just so I can go back to completely stock-appearing under the hood. I'll be out of town for a week, but if you think you're interested in it shoot me a pm and I'll get back to you on it.