650 double pumper carb on thumper heads,fcam.

dastang2

Active Member

Dec 11, 2003

2,020

0

46

tx

Sep 29, 2006

#1

• Sep 29, 2006

• #1

hello, i do not think this carb is right for my car. i think i need a 625 at the most. what do you guys think. the carb runs rich and hesitates and stumbles badly when pressing the gas to take off and cruising. it needs a tune but i would like other opinions on this. i have the thumper heads,fcam and long tubes with a 5 spd.

 

dragnazz5.0

My "0" key d0esn't w0rk, s0 I have t0 use the zer0

Nov 19, 2005

815

5

18

mooresville, nc

Sep 29, 2006

#2

• Sep 29, 2006

• #2

probably a little big, but you could always try jetting it down. my car has a slight stumble to it when cruising if you let off the gas and than push it again. i would try jetting it down one step depending on how rich it actually runs

 

85_SS_302_Coupe

it sucks (I know) to be on the receiving end

15 Year Member

Nov 11, 2003

6,945

1,598

223

Northern KY

Sep 29, 2006

#3

• Sep 29, 2006

• #3

Just remember that jetting down doesn't solve the problem, because you trade too much fuel for too much air and the responsiveness of the carb is compromised. I have a 650 on mine but i had intended on building a 351W and it never happend so now that's what i've got. Once i have heads and a cam then we'll see how it runs.

Typically you don't need more than a good 600 for a mild 302. Actually BG make a 575 that runs like a raped ape on mild HCI combos.

 

R

R2D2

Sep 29, 2006

#4

• Sep 29, 2006

• #4

too much pump shot is the problem, its not to big

 

dastang2

Active Member

Dec 11, 2003

2,020

0

46

tx

Sep 29, 2006

#5

• Sep 29, 2006

• #5

i heard that people put a smaller secondary squirter on them to make them more responsive. also it tries to dies if i don't gas it when i stop hard. that would be the floats. this is a mechanical secondary carb. it is a spreadbore