Small Block & Big Block Chevy Specific - bbc carb jets size?
TTSSZ
07-03-2007, 10:16 PM
I have a 427 bbc, 11 to 1 comp. 425hp
I have a 850 holly carb, what jets should use for the street as a starting point to getting it tuned in?
I was told by a friend to ditch the 850 and put a 600cfm.
GOaT Cheese
07-04-2007, 02:10 AM
I have a 427 bbc, 11 to 1 comp. 425hp
I have a 850 holly carb, what jets should use for the street as a starting point to getting it tuned in?
I was told by a friend to ditch the 850 and put a 600cfm.
I wouldn't listen to your friend, an 850 on a 427 is fine. And then go here, http://www.mortec.com/carbs.htm
rat454
07-26-2007, 12:41 AM
The 850 dble pumper can be a finiky witch...but it is not too big for a 427
If I remember right,
for open pelnum intake (torker, victor) I ran
left front 80
right front 76
left rear 76
right rear 78
If divided (performer, performer rpm) I think it was 74's in the front and 78's in the back.
Either way I had better luck running a standard bore 3310 than a spread bore...
G
GOaT Cheese
07-26-2007, 01:24 AM
Holly cow, what is the purpose of running such goofy jetting on a single plane. Did your carburetor have three different sized buterflies?
CoozePoodle
07-27-2007, 03:30 AM
The 850 dble pumper can be a finiky witch...but it is not too big for a 427
If I remember right,
for open pelnum intake (torker, victor) I ran
left front 80
right front 76
left rear 76
right rear 78
If divided (performer, performer rpm) I think it was 74's in the front and 78's in the back.
Either way I had better luck running a standard bore 3310 than a spread bore...
G
WHAT???? that just made my eyes bleed.
TTSSZ
07-27-2007, 08:43 PM
The friend that told me to go small has a nice little speed
shop with a real nice dyno. He said that with dyno's and
computers, they have found its a fact that it takes 1.25cfm
to make 1 hp.
So the 600 is good for 480 crank hp.
I'm only making 425 or so.
The small bore is also supposed to make more air velocity and
draws the fuel better.
GOaT Cheese
07-28-2007, 02:02 AM
The friend that told me to go small has a nice little speed
shop with a real nice dyno. He said that with dyno's and
computers, they have found its a fact that it takes 1.25cfm
to make 1 hp.
So the 600 is good for 480 crank hp.
I'm only making 425 or so.
The small bore is also supposed to make more air velocity and
draws the fuel better.
Tell that to NASCAR, alot of 800 h.p. small blocks running around on Sundays with 600 cfm carbs on them