I feel I am chasing my tail.
I start up the chevelle and it shows 7 pounds fuel pressure on the regulator, go up the road and get it hot with a high speed pass, and pull back in the shop and it shows 3 pounds and will slowly drop to zero and pull all of the fuel out of the front bowl, so you think vapor lock right? Well that is what it acts like for sure, but its never did it before on hotter days than it is now and I did not change anything. All of a sudden after 3 years it acts up.
540 cubic inch. clay smith mechanical big block fuel pump. 1000 cfm AED 4150 carb.
1/2 inch steel braided fuel line from the tank to the pump and then 1/2 inch line to the fuel regulator and then 1/4 inch lines to each bowl, they are all wrapped with reflective heat resistant tape, I used the original 3/8 fuel line for the return to the tank. I checked the inline fuel filter and it is good. I have have raced this car in vegas at 100 degrees without a any issue, hot lapping it. Before I start throwing parts at it I would appreciate some insight from anybody who has seen something similar. Maybe the fuel pump is giving up but I don't think so because the car will light right up 2 hours later when the fuel bowl fills with 7 pounds on the regulator. Thanks ahead of time for your insight.
Hi Mike, I've had similar issues before with my old engine and combo. Be glad yours is a 70, my 69 is the one
with the extra tube in the gas tank so when it was 1/2 to 3/4 full, fuel would be siphoned out of the tank.
I also now have the Clay Smith BBC fuel mechanical fuel pump. When I replace my gas tank with the Tanks, Inc larger tank, I'll use the 3/8 line as a return line. I have a heavy duty continental 1/2 inch I.D. fuel line at the ready.
It's not stainless steel, but a 300 psi heavy duty industrial fuel rated hose.
I bet, if you drive her around and use of the winter fuel, you'll be okay with the summer blend.
But summer blends might not be out as usual, because I bet, with the lack of driving by Americans
during corvid-19 they've got excess stock of winter fuel and don't have room for summer blends
until they sell all the winter fuel.
Oh I don't know if this would help or not, but I'm using one of the clay smith in-line regulators
that are typically used with Enderly Fuel Injection, I have mine at the back end of the carb so fuel
is constantly flowing. Let me link that here: LINK
You can see the brass body underneith the fuel log with the arrow
pointing in the direction of flow. Ideally they say, 1/2inch should be used each way
for best results, but I think it should be okay sending back through 3/8 inch steel line.
Question, aren't the bowls in these carbs suppose to close when the float level is raised?
How are your bowls draining of fuel? Is it sucking it back through? I guess you don't know.
BTW What does your Chevelle run at the strip?