Use the one that's the same as the one you're removing. A gasket with a different thickness will change the relationship to the thermostatic choke spring.
There is some theory involved related to tuning for a certain level of performance, but you'll never notice the slight difference with a different gasket. The length of the intake runners has an affect on which rpm range the engine makes the highest torque. This was one reason, among others, that the really tough 225 c.i. slant six was used in two-ton dump trucks. Their long intake runners gave the engine more torque on the low end to help them get going.
In stock trim, the 318 is a solid engine, and much lighter than comparable GM and Ford engines, but it's not a high-torque or high-power engine unless other modifications are done. You must remember too, that for every modification that gives an improvement in one area, you give something up somewhere else.
Jun 18, 2015 at 8:44 PM
