91 DD build

[ChevLoRay]

Other comments on the headers....

One of the issues that headers bring about is a change in the exhaust gas temps. When an engine exhausts through a set of headers, the gasses move more freely and that may affect the mixture, i.e., more/less rich. If it becomes leaner then you may have to put a heat shield on the starter. In fact, it wouldn't be a bad idea. Which carburetor are you running? My personal experience with an Edelbrock 1405 (manual choke) showed it to be a "fat" carburetor due to the .100 main jets. When I changed carbs to an Edelbrock 1901 (Q-Jet), the change in mixture from a leaner-running carb caused hot start problems that were solved by the installation of the heat shield.

But, the purpose of headers is to move the exhaust gasses more efficiently. When you accept the fact that an internal combustion engine is an air pump, you also have to understand that anything that makes it easier to get the air out will also make it easier to get the air into the engine. Getting the air to flow better makes the engine more efficient. So, a set of headers, a cam that has a little more lift and duration along with a carburetor that flows more CFM than the stock one also will benefit from a low-restrictioni air cleaner (K&N, for example). But, these things all fall under the category of "speed costs money.....how fast do you want to go?"