Rich wot but reducing secondary jets isn’t helping?

[beanhead]

Certainly sounds like a Chevy problem.....they seem to have similar difficulties. Now is the time for the MSD or Pertronix proponents to proclaim the benefits of their equipment. Seriously, another check for uniform fuel distribution/cylinder combustion efficiency, is Exhaust Gas Temperature, measured at the cylinder head outlet with individual thermocouples, one per cylinder. This will show which cylinder is richer or leaner, based on exiting gas temps, perhaps in the 1200° - 1400° F range. Down stream oxygen readings or air / fuel ratios are helpful but are an average of the engine's combustion process. Individual EGT will pinpoint which cylinder is not performing uniformly with regard to the others. The other possibility is a bad/loose connection or a bad ground....but not likely. Just my opinion of course.
BOB RENTON

 

[Sonny]

Certainly sounds like a Chevy problem.....they seem to have similar difficulties. Now is the time for the MSD or Pertronix proponents to proclaim the benefits of their equipment. Seriously, another check for uniform fuel distribution/cylinder combustion efficiency, is Exhaust Gas Temperature, measured at the cylinder head outlet with individual thermocouples, one per cylinder. This will show which cylinder is richer or leaner, based on exiting gas temps, perhaps in the 1200° - 1400° F range. Down stream oxygen readings or air / fuel ratios are helpful but are an average of the engine's combustion process. Individual EGT will pinpoint which cylinder is not performing uniformly with regard to the others. The other possibility is a bad/loose connection or a bad ground....but not likely. Just my opinion of course.
BOB RENTON

any chance it could be torque converter or trans related? The car has a 2000 stall converter in it. When I test the car I’m going 40-45 mph, drop it in second, and add part throttle it’s great. Wide open is when it just can’t seem to speed up. I’m probably close to 2000 rpm at that point. ?

 

[beanhead]

Next time you try that, go throttle to the floor and see what happens since WOT is when you're having the issue.

 

[Sonny]

Next time you try that, go throttle to the floor and see what happens since WOT is when you're having the issue.

That’s what I’m doing. Wot at a 40 mph roll in second gear.

 

[beanhead]

That’s what I’m doing. Wot at a 40 mph roll in second gear.

Oh okay I saw 'hit 2nd and add part throttle it's great'.

 

[Stroker68]

I checked my plugs. They are white. I think my gauge is a liar and a fat mouth. Holley tech told me the same thing. Going back to 72s and will check again. Thanks.

White means lean. Probably already know. No rear power valve? 4150 conversion means secondary metering block right. Some guys that run no secondary power valve will jet up like 8 sizes to keep from going lean at wot. PV regulates fuel based on vacuum level. Not much vacuum at wot. Run it rich then back down by 2 at a time till deer hide tan. Your motor will love it.

 

[Sonny]

White means lean. Probably already know. No rear power valve? 4150 conversion means secondary metering block right. Some guys that run no secondary power valve will jet up like 8 sizes to keep from going lean at wot. PV regulates fuel based on vacuum level. Not much vacuum at wot. Run it rich then back down by 2 at a time till deer hide tan. Your motor will love it.

thanks but I’m now using an Edelbrock AVS2 800 cfm carb. Should have been more clear.

 

[Sonny]

thanks but I’m now using an Edelbrock AVS2 800 cfm carb. Should have been more clear.

Update. Drove the car yesterday with the windows up (first day in the 60s here in Florida) and I really noticed a lot of pinging (under part throttle load) that’s not noticeable with the windows down. I decreased the timing from 18-36 to 15-33 and wow! Pinging gone and so was the wot “bog”. Wasn’t a fuel issue at all. Just too much total timing. Also swapped a light silver spring to two blue ones and that helped too. I guess the moral of the story is heavy car, rb 440 with a long stroke, 276 gears, higher compression = less total timing.