do i need to upjet my carb to match new exhaust?

[uk mark]

Hi Everyone,
I have recently fitted new Headmann headers and a stainless steel exhaust system which has got rid of he catalytic converter and made the car sound a lot better!
After running it for 100 miles or so i checked the plugs and they are very white in colour which suggests that the engine is running lean.
If anyone has done anything simular or has info on Rochester M4MC carb then i would be grateful for any advice.

Many thanks,
Mark.

 

[motorman]

what is the # stamped on the side oof the carb?

 

[uk mark]

upjetting

Hi Motorman,
The carb is a Rochester quadrajet with the following number: 7045222 R6 0295.


Thanks.

 

[motorman]

mark,i would try a "DA" (.040 dia tip) to replace your secondary rods which are CH (.057) to richen up full throttle. your pri jet should be a # 72 and i would try a #74 for starters.

 

[uk mark]

Thanks Motorman,
It'll take a while for the bits to get here but I'll let you know how i get on.

MARK.

 

[motorman]

these parts can be gotten from a speed shop that handles edelbrock . they list a .041 sec rods part# 1951 and .074 jet is part# 1974

 

[JHL]

Hi Mark

I bought some jets and rods for a quadrajet from Speed and Spares America - 01372 745747. They had them on the shelf and they were only a few pounds. Alternatively I have used John Woolfe Racing for some bits and found both places very helpfull and reasonably priced.

J.

 

[uk mark]

Thanks for the info JHL,
The car looks excellent. I'll check out the website.