Admiral
Well-known member
To make a long story short, I was running an EBU center section (1” venturi) on my nearly stock 251-cubic-inch flathead V8. With the appropriate tall boosters, this setup ran well, though I heard using a smaller carb could be better for a mild engine like this, so I recently swapped in an 8BA center section (15/16”) with the correct boosters (and yes, I plugged the Load-o-matic port). I cleaned all the new parts up, put everything together carefully and set the float level, and the car felt noticeably more powerful, with crisp throttle response. It also started way better when hot, an unexpected bonus.
But today, I went to move the car to put something in the attic and the engine was shivering at idle and didn’t feel like it was running on all eight cylinders. I checked the wires and made sure each plug was getting spark, but that didn’t change anything, so I pulled a plug. It was as black as tar (just dusty, no oil or carbon chunks). I yanked couple others and they were dark, too. What caused this? I’m using the stock power valve and I’m pretty sure it’s not blown since the car drove so well. The jets should be stock as well, No. 51 if I recall.
I was farting around with AI and it suggested jetting down to 50 or even 49 because the "strong vacuum signal is pulling too much fuel," something like that, but I wouldn’t think that’s the issue. If anyone can point me in the right direction it’d be appreciated. I've never had this problem before. The plugs were a perfect chocolatey brown with the EBU center section and tall boosters, and with the Strombergs I've tinkered with in the past.
But today, I went to move the car to put something in the attic and the engine was shivering at idle and didn’t feel like it was running on all eight cylinders. I checked the wires and made sure each plug was getting spark, but that didn’t change anything, so I pulled a plug. It was as black as tar (just dusty, no oil or carbon chunks). I yanked couple others and they were dark, too. What caused this? I’m using the stock power valve and I’m pretty sure it’s not blown since the car drove so well. The jets should be stock as well, No. 51 if I recall.
I was farting around with AI and it suggested jetting down to 50 or even 49 because the "strong vacuum signal is pulling too much fuel," something like that, but I wouldn’t think that’s the issue. If anyone can point me in the right direction it’d be appreciated. I've never had this problem before. The plugs were a perfect chocolatey brown with the EBU center section and tall boosters, and with the Strombergs I've tinkered with in the past.
