disapoining et

-
I have a 64 sport fury with a 440 +.030 3k stall 727that uses a 750 race demon. We ran it with several carbs, and my friends 650 holley gave the best 60 ft. We tried an 850 and an 800 both were much slower. All were double pumpers. final e.t. was 12.12@110mph. When I started it was running 13s. All gains were with carb and tuning. What I am saying is you need a smaller carb to help the 60 ft.Try different timing, and we still need to know if your 60 ft was from bogging or spinning. Hard to give a recommendation without that.
 
furyus2 said:
I have a 64 sport fury with a 440 +.030 3k stall 727that uses a 750 race demon. We ran it with several carbs, and my friends 650 holley gave the best 60 ft. We tried an 850 and an 800 both were much slower. All were double pumpers. final e.t. was 12.12@110mph. When I started it was running 13s. All gains were with carb and tuning. What I am saying is you need a smaller carb to help the 60 ft.Try different timing, and we still need to know if your 60 ft was from bogging or spinning. Hard to give a recommendation without that.
Click to expand...

did you play with pump cams, squirters? Or just bolt it on and it slowed down?
 
hi, on the T.Q. all we do is lower or raise metering bar for primary jetting, and open or close air door for sec jetting. why is that hard?? very easy to tune.air door opening will richen or lean sec, moving metering bar will richen or lean pri mixture.
 
Oh my god, this guys never coming back!. My thoughts, pull back the cam timing /or pur some gear in it. The old 280 Comp,always needed : 3:90-4:10 minimum. A GOOD wrench ,can get you down ,to 3:50-'s - 3:70's. You are ,working too hard.
 
Thanks for all the replies and suggestions! Got me a lot to digest. I am not so worried about keeping the set up I have, the guy I bought the car from had it set to just cruise once in a while. If I have to change things its fine. I want to get it right the first time.
What in seeing is I need more gear, slicks and pin down my tuning. I will also look to open the headers next time I run(2 1/2" exhaust, someone asked earlier. Will upgrade to TTI 3" down the line.)
Won't be able to mess with the old girl for a few days, but I will look at all the things y'all said and post what I find.
 
Simple as this: Your speed is really low and suggest even with slicks you don't have the power to get out of the 14's. Whatever the problem is, it's costing you about 80 horsepower. You DO NOT NEED MORE, like a manual vb, or 4.10's to fix your current problem. My stock 318 4bbl with stock manifolds and 2.94's would be on your quarter panel to the finish. Your set up should push deep into the 12's. Swap a different carb on of 750 cfm's. eddy or holley dp. One drive around the block will let you know. When you find your problem, you'll think you dropped in a new motor. Yes, it will be that obvious... Good luck
 
318willrun said:
Simple as this: Your speed is really low and suggest even with slicks you don't have the power to get out of the 14's. Whatever the problem is, it's costing you about 80 horsepower. You DO NOT NEED MORE, like a manual vb, or 4.10's to fix your current problem. My stock 318 4bbl with stock manifolds and 2.94's would be on your quarter panel to the finish. Your set up should push deep into the 12's. Swap a different carb on of 750 cfm's. eddy or holley dp. One drive around the block will let you know. When you find your problem, you'll think you dropped in a new motor. Yes, it will be that obvious... Good luck
Click to expand...


x2
 
808 DUSTER said:
Took my 72 duster to the track for the first time, I was a bit disappointed to say the least. Mabey my expectations were to high, but I feel like my combo is off.

Specs.
1972 duster
383 hp block
906 heads, bowl work and gasket match
1.6 roller rockers
Comp cam 280h grind
3000 10inch turbo action converter
3.55 gears
26 tall street radials

Best result of the day
60 foot- 2.25
330 et- 6.20
1/8 et-9.47
1/8 mph- 75mph
1/4 et- 14.69
1/4 mph- 93.76
Around 5200 rpm

After talking to my engine guy his suggestions, while keeping it treatable are
Manual valve body
Mopar performance leafs(replace worn out stock ones)
Gas shocks to replace the air shocks
Slicks 8x26 for track days
M1 intake to replace eddy performer.

I would like to see low 12s. Maybe someone has a similar set up they can share or some ways to get to where I want to be.
Click to expand...
ok I will give this a try without getting bashed too hard,first thing I would do is get rid of the gas shocks and get a pair of shocks for a 60s station wagon,preferably the old OEM ones,then take the clamps off behind the rear wheels and put another one on the front,then put at least a 4 degree shim under the spring perch.(you can get these at napa or a place the does truck front end work)and while you're under there take your pinion snubber out and throw it away you don't need it any more you're putting big boy pants on that thing now!..that should pretty much get you hooked..if your timing is around 38 I think you're in the ballpark and im think you have spring kit in your dizzy right?any ways after a hard run pull a plug and see where your timing is at (to do this look at the I will call it the wire that comes up from the plug with the bend in it,)your timing mark will show there.and It should be in the middle of the bent piece if its higher back it off a little bit if its lower ad some to it.but it will show you where it wants to be.and I think I would try that intake just because I never had one.and I would think you will want to be in the 70s range for jetting (rusty ratrod would be the one to ask for that.or anything else as far as that goes)and if you're running the blue holly regulator they will not flow over 90 cfm's of fuel if more is used you will need two..with separate lines.and the converter should be flashing at least 1000 rpms above were the cam is starting to work.have you tried flashing it to see where it comes in.you do that in high gear if you have a manual valve body in it.I feel this motor should run In the 11 et. range with no trouble and still be a drive any were kind of car.......just trying to help ya........Artie
 
What bushing is on the MSD distruibutor.

Pro-billet, I'd run the black if the engine will start easily when warmed up. If it won't start with that one, go to the 21* bushing. I'd run the engine at anywhere from 16-22 initial timing. Find the point the engine won't start easily and use the appropriate bushing.

Converter slip is about 17% which is horrible.

I'd find a decent good running 750 DP and put it on the car and see what happens. Sometimes those super fancy altered carbs are a total POS when in real world use. I wouldn't run a vacuum sec carb, just my opinion. You can get really good mileage with a DP carb, it's all in the tune up and how heavy the right foot is!
 
i am using the pro-billet dizzy with black bushing and 1heavy-1light silver spring.
the carb is a holley 4160-4224 660cfm center squirter, mech secondaries. it has been reworked and flows 952cfm with #85jet. when i read the plugs after the run i had 1 tread dry so it is a little rich, might step down in jet size. but before i do that i want to check the rest of the suggestions on tunning posted here.

Thanks again for all the detailed responses!
 
How about running it on a chassis dyno and posting up the power curve? That might be a good place to find out what you should be running on the track.
 
You have a carb that was designed to be used in pairs on a tunnel ram. It's not a good carb to run on a single 4 barrel and is really an ON/OFF style carb.

Your jetting is horribly imbalanced with an 85 front and it has the stock plate in rear. It's jetted 85/73 if I'm correct. That will not make the engine happy.

If it was me, 750 DP and a 1" open spacer and I'd bet it will run much better
 
crackedback said:
You have a carb that was designed to be used in pairs on a tunnel ram. It's not a good carb to run on a single 4 barrel and is really an ON/OFF style carb.

If it was me, 750 DP and a 1" open spacer and I'd bet it will run much better
Click to expand...
X2 for that........
 
crackedback said:
You have a carb that was designed to be used in pairs on a tunnel ram. It's not a good carb to run on a single 4 barrel and is really an ON/OFF style carb.

Your jetting is horribly imbalanced with an 85 front and it has the stock plate in rear. It's jetted 85/73 if I'm correct. That will not make the engine happy.

If it was me, 750 DP and a 1" open spacer and I'd bet it will run much better
Click to expand...

I agree 100%
660 is for HIGH RPM Use on Tunnel ram in pairs and it is jetted back *** words
750 DP #82 front 5.5 power valve and 84's or 86's in the rear
What intake do you this 660 sitting on?
 
805moparkid said:
did you play with pump cams, squirters? Or just bolt it on and it slowed down?
Click to expand...
I started with the 850,it was running fine, no bogs or anything. I think it was a velocity issue. I worked with the carbs just to the point of working correctly. Didn't change jets, or squirters, so I think there was more in it there. Just my opinion, but I don't think you need a huge carb on a BB Mopar. Tried changing from a Torker 2 to an eddy rpm, but have never made it back to the track.
 
Smaller carb will typically react quicker thus better 60'. Will likely suffer on the top end.
 
Whatever you get for a holley carb, start very close to the baseline jetting that it came with from Holley. Most 4779 750DP's are in the 70-72 range primary with a power valve and 80-82 secondary. Easy to find and relatively inexpensive.

With a 1" spacer, lots of times they like to be jetted up ~2-3 steps front and rear. Test it at the track. See if it picks up MPH after jetting it up. If it did, you are headed the correct direction. Keep going until MPH slows down.

No power valve in that 660 carb you have which is another issue with driving around town. IMO, it may flow 900+ cfm if it got 3+ inches of vacuum drop... not the std 1.5". Can that 660 carb and move on to something more appropriate. If someone sold it to you knowing what you intended to run it on, they did you no favors!
 
Agree with crackedback on the 4779 jetted up 2 sizes sitting on a 1" spacer. If you know a bunch of racers someone is bound to have known good carb kicking around that they'd let you try.
 
Hear is an "off the wall crazy"! With it idling, pull the plug wires off the distributer to make sure each cylinder dies it down. If it idles down (and rough), plug that wire back in and move to the next. Had a guy with a dart that couldn't figure out his problem, took it to a couple of mechanics and no luck. I found a dead wire. He was running on 7 cylinders. One plug wire and PRESTO, that car sprung to life! Your issue is going to be at least that drastic, and yes I agree with everyone else, that carb needs replaced.
 
crackedback said:
You have a carb that was designed to be used in pairs on a tunnel ram. It's not a good carb to run on a single 4 barrel and is really an ON/OFF style carb.

Your jetting is horribly imbalanced with an 85 front and it has the stock plate in rear. It's jetted 85/73 if I'm correct. That will not make the engine happy.

If it was me, 750 DP and a 1" open spacer and I'd bet it will run much better
Click to expand...


x3 (or 4?)
 
furyus2 said:
I started with the 850,it was running fine, no bogs or anything. I think it was a velocity issue. I worked with the carbs just to the point of working correctly. Didn't change jets, or squirters, so I think there was more in it there. Just my opinion, but I don't think you need a huge carb on a BB Mopar. Tried changing from a Torker 2 to an eddy rpm, but have never made it back to the track.
Click to expand...

just wondering cuz my slant likes the 750 over the 600..
 
The 1:1 linkage having all 4 throttle blades open at the same time is a bad idea as well. That can't be changed to a progressive set up because of the squirter location/function. If it has been altered to progressive the carb is now junk without new linkage.

Carb is the first item that needs to be gone from your set up IMO.

It's the wrong carb for this use.
 
I got to say it.. Its the big block that is slowing your A-body down. Everyone likes the idea of a big block in an A-body, and that It is going to be soo fast.. Reality check here.. I know this is not helping your need, and this could be covered under a whole different thread, but like I said had to say it.. A Stock 340/ good 360 with stock cam and manifolds run better than that all day long at the track.
More than likely get your timing right and Carb right, and proper traction you will pick up 3-5/10ths. Like the guys are saying. your not going to see low 12's, without a lot of changes in gear, traction, and more H.P
 
You must log in or register to reply here.
-

Back
Top