different 318 question

What we don't know is what the OP means by "seems to run out of steam after 3500rpm"..... Stops completely? The torque drops off? (Meaning the seat-of-the-pants feel of begin pressed back in the seat starts to drop off?) There are several interpretations of such a statement so there will be different ideas about what is actually happening, like in post #3: "was way out of the power range for a stock cam but it would go there"

BTW, OP, make sure your duals don't have glass pack mufflers where the fiberglass is 'leaking' out of its proper place and plugging the exhaust.