I've got a 67 Chrysler 300 with 440 TNT engine, auto and 3.55 Sure Grip. I have and Edelbrock 750 cfm Performer carb with electric choke and I've having some tuning issues with it.
1) I know the 440 TNT engine came with a Carter AFB carb; but what was the cfm???
2) HOW do you determine which step up spring to use for the primary metering rods?? I have the silver spring in there now which stages at 8" of Hg. The carb came with the yellow spring (I think) that staged at 4 or 5" Hg. I read somewhere that you should select the Holley power valve opening depending on your engine vacuum; choose the power valve that opens at 10" Hg less than your vacuum reading at cruise.
Does the same rule apply for Edelbrock carbs??? If not, how do you determine that?
That is helpful. I've gone to calculators for carb cfm sizing and basically they say around 700 cfm is the right size for a 440 as we described. Too bad there are so few intermediary sizes supplied by the aftermarket.
Joined: Mon Oct 10 2005, 09:48PM
Location: Calgary Alberta Canada
Posts: 305
I had issue with my Edelbrock Performer carb on my 67 440 too. Finally went back to the original carter and after some tweaking i like what i have got. Runs nice.
For the spring I think mine opens at 8 inches. Depends on the jetting, motor specs and elevation. It a trial and error section method.
Thanks guys for the responses! The BIG problem I've been having with my car is because the original owner wanted his new 67 300 to be like the 62 300 H he traded in. He had dealer installed 2 Carter AFBs on a single plane manifold (like the 300 H had). This set up probably never worked quite as expected. The selling dealer had the carbs installed wrong; the FRONT carb was the primary instead of the Back carb as on the 300 H. So the operating carb linkage was kinda funky. The front carb had to push back on the linkage to open the rear carb.
Anyway, the original front carb that was on the carb developed problems after I got the car. Long story short; I got an Eddy Performer intake and have tried several different carbs and it never seems to be quite right.
Now I've got an Eddy Performer 750 cfm carb on it with electric choke. It runs fairly well and the fuel econ is not too bad; BUT things aren't exactly right either.
I'm just gonna live with it for now until I can figure out something better.
Joined: Thu Oct 13 2005, 05:11PM
Location: Fort Worth, Texas
Posts: 124
I have an AVS 4640S which seems to work fairly well, except for hot starts. Thinking of going with Fitech fuel injection if I can get the fuel tank situation figured out. I haven't found a replacement fuel injection tank for a C body yet.
I guess hot starts are going to be a bit of a problem with carburetors and todays fuel..All that ethanol!
How about you guys out there? I live in Northern Virginia and most of our fuel is 10 - 15% ethanol...On hot days after driving my car, the car smells like some old alcoholic! What about the fuel in your area???
Joined: Sat Mar 29 2008, 03:36PM
Location: North eastern Wis.
Posts: 1638
We have the same ratings here. Half way between the Equator and the North Pole, elevation might be lower (?). My stuff all runs just fine on it. I never noticed any odd odor. Of course, non of my stuff is high compression either.
Joined: Thu Oct 13 2005, 05:11PM
Location: Fort Worth, Texas
Posts: 124
67Chrysler300 wrote ...
I guess hot starts are going to be a bit of a problem with carburetors and todays fuel..All that ethanol!
How about you guys out there? I live in Northern Virginia and most of our fuel is 10 - 15% ethanol...On hot days after driving my car, the car smells like some old alcoholic! What about the fuel in your area???
The odor of the EPA swill is toxic. The high reid vapor pressures give operations troubles and make it even more aromatic. It's not a problem for newer cars with evaporative emission controls but our older stuff that vents to the atmosphere is just awful.