Home Menu

Menu


Pontiac - Street No question too basic here!

          
PY Online Forums - Bringing the Pontiac Hobby Together > General Classic PONTIAC TECH > Pontiac - Street > tuning help/455 jetting
Reply
 
Thread Tools Display Modes
  #1  
Old 06-05-2007, 10:29 PM
dave s dave s is offline
Junior Member
  
Join Date: Jun 2007
Location: alden ny
Posts: 10
Question tuning help/455 jetting
please help ! I have a 67 gto w/ th400 390 gear 2500stall 28" tire. the engine is a 462 , 6x heads bowl work,port match,2.11/1.66 valves,harland sharp 1.5 rockers,comp cam xtreme energy 270 ,intake performer ,ram air exhaust manifolds,2.5 flowmaster full system. 9.7 compression.The carb is a 1971 caddy 472 q-jet. The problem I have is part throttle tuning @2000 rpm,I cant get it to lean out.I used the choke to tip in and it drops rpm.I started w/.073 jets .042rods .041sec. I adj. the apt full lean no change but the car ran pretty good .good idle good power,12" vacuum.Then I tried 77jets .047rods .041sec. The car seem to have alot more power but still rich w/ tip in.12" vacuum. I tried 9 -10-12 deg. timing , no change.Am I even close w/ this set up?? I read about people drilling the main air bleeds , if so how much and do you drill all four? Thanks for your help!!!!

Reply With QuoteReply With Quote
  #2  
Old 06-05-2007, 11:09 PM
Cliff R's Avatar
Cliff R Cliff R is offline
Ultimate Warrior
  
Join Date: Nov 2000
Location: Mount Vernon, Ohio 43050
Posts: 18,153
Default
What size are the main airbleeds? Nearly as I can remember, those carbs have small airbleeds and small jets?....Cliff

__________________
If you can read this, thank a teacher. If you can read this in English, thank a Veteran!
https://cliffshighperformance.com/
73 Ventura, SOLD 455, 3740lbs, 11.30's at 120mph, 1977 Pontiac Q-jet, HO intake, HEI, 10" converter, 3.42 gears, DOT's, 7.20's at 96mph and still WAY under the roll bar rule. Best ET to date 7.18 at 97MPH (1/8th mile),
Reply With QuoteReply With Quote
  #3  
Old 06-06-2007, 02:47 PM
dave s dave s is offline
Junior Member
  
Join Date: Jun 2007
Location: alden ny
Posts: 10
Default main air bleeds
Hi Cliff the main air bleeds are .050

Reply With QuoteReply With Quote
  #4  
Old 06-06-2007, 06:28 PM
MrPushrod's Avatar
MrPushrod MrPushrod is offline
Ultimate Warrior
  
Join Date: Nov 2005
Location: Reno, Nevada-4500'
Posts: 1,464
Default
Maybe buy a holley dp 850?

Reply With QuoteReply With Quote
Reply

« Previous Thread | Next Thread »

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts
BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump


All times are GMT -4. The time now is 03:45 AM.

 

About Us

The PY Online Forums is the largest online gathering of Pontiac enthusiasts anywhere in the world. Founded in 1991, it was also the first online forum for people to gather and talk about their Pontiacs. Since then, it has become the mecca of Pontiac technical data and knowledge that no other place can surpass.

 




Contact Us Home
Copyright © 2017