My modified ’54 3100 is propelled by ‘67 283. The engine was rebuilt some time ago, including a non-stock cam. I have no further details about the rebuild. The carburetor is an Edelbrock 1405 (600 cfm) on an Edelbrock dual plane manifold. The acceleration performance is very good. However, I have been dealing with a low end problem - the engine tends to falter and /or shut down at idle, only when warm.
I will skip an account of long trial and error; I believe I finally have a diagnosis. I recently took a heat reading at the base of the carburetor. I read 175 degrees f. My fuel is 91 no ethanol. I have concluded, after much research, that the 91 fuel will start to bubble at approximately 135 degrees.
I am looking at a couple of heat shielding products for placement between carb and manifold. One is .5” and made of a wood composite. It has good reviews pertaining to dealing with the type of heat issue I am dealing with. The other is .32” , made of a rubber-like material, and is said to be specific to heat issues.
Any input on this type of problem would be appreciated here , as well as commentary on the 2 products being considered.
My manifold does have an exhaust port. It is capped at the downstream , external point. I am hoping to avoid removing the manifold and capping the other end because I just re-installed the danged thing for the 3rd time after correcting a crankcase ventilation problem. Don’t want to go through that effort again if I don’t have to. The spacer placement is easy, and I think it is the right thing to try next.
