Yellow Bullet Forums banner

1 - 10 of 10 Posts

·
Member
Joined
·
23,395 Posts
Discussion Starter #1 (Edited)
408w-13.5 to 1, AFR 205 headed motor 260/270 (i think it was) .670 roller cam., 950 Quick Fuel, 9" Ford w/4.86 Gear, Powerglide w/PTC 8" 5300 Converter. Shifted at 6500 but it wants to be shifted higher.

This combo is in an 87 Mustang and I'm guessing it's 2800 pounds with driver the 30 x 10.5 -15 Goodyears.
The problem is it's very lazy off the bottom end. The timing is at 30 degrees and the carb is stock in every way with 78 front and PV and 86 rear w/no PV.

This weekend was the first few passes on the car and it ran a best 6.76 @ 105.62 off a 3000 rpm foot brake. My son said it stumbled a little at that rpm and worse at anything less. We will normally be running a trans brake and leaving off the 2 step at around 4500 or more I'm guessing.
The mph suggests the car should be running in the 30's or 40's. The best I could tell the car is 2/10 slow in the 60' and 3/10 slow at the 330 and about 3/10 at the 1/8 mile mark. Best 60' was 1.57 and best 330' was about 4.44. I had him check the converter at slow speed in high gear and it flashed to 5300. I think we may be way fat or way over carbed. Any help or suggestions please. The car ran fine and does not smell pig bog rich at idle.
 

·
Registered
Joined
·
5,181 Posts
That carb should work excellent on your build. I didn't see what fuel you where running but timing seems on the low side. Do you have the advance locked out in Dizzy???

Bog on foot brake lanch sounds like Accelerator pump circuit problem (cam adj, bigger pump, bigger nozzle).
 

·
Registered
Joined
·
4,182 Posts
Like what was said above^^^^^^^^^^
Also try leaving at idle, this might help by letting the converter get a running start.
-Check timing(tune)
-Check plugs(yes what it needs)
 

·
Registered
Joined
·
813 Posts
I have a 400 ci. Weesor with a HP950. It's jetted 74 fronts with a P/V and 82's rear with it plugged.

Look at the plugs and see what they look like after a run.
 

·
Member
Joined
·
23,395 Posts
Discussion Starter #5
That carb should work excellent on your build. I didn't see what fuel you where running but timing seems on the low side. Do you have the advance locked out in Dizzy???

Bog on foot brake lanch sounds like Accelerator pump circuit problem (cam adj, bigger pump, bigger nozzle).
My son was running the TT 114. He says it runs like a bat out of hell after it shifts into high gear. Yes, the advance is locked out. Really strange.
I love the carb.
 

·
Member
Joined
·
23,395 Posts
Discussion Starter #6
I have a 400 ci. Weesor with a HP950. It's jetted 74 fronts with a P/V and 82's rear with it plugged.

Look at the plugs and see what they look like after a run.
Are you running a glide? 74 front huh
That's what I run in my little 347 with an 750hp and it's dead nuts.
We are talking about 1/10s of seconds here though. Can a rich car do that and then fly after it gets into high gear?

The quick fuel carb is factory jetted 78pv and 86 no pv.
 

·
Butch
Joined
·
8,208 Posts
Often times the over ride spring wears causing this condition, a simple fix, which I do on all new carburetors

Watch the accelerator pump arm, when you stab the throttle does the adjustment nut lift off the arm? Many do, and if so, pull the override spring out and place some small washers (2) under the spring so it provides MORE pressure, and compresses the accelerator pump and not the override spring, this is a cause of many many bogs/hesitations
 

·
Registered
Joined
·
2,240 Posts
how far are the idle mix screws open?
if you back the idle stop screw off,how much do have to turn it in to reach your desired idle rpm?
 
1 - 10 of 10 Posts
Top