So with plenty of interest in seeing what an ECONO 347 would do with Magnum heads on it in lieu of the '302's I ordered some. These are new castings from a new company. They are priced well and here is the overview. The good: New castings Low cost Availability OEM appearance (I think these are cast from OEM core boxes) Seat inserts both intake and exhaust The not so good: Rough casting surface Casting is OEM replacement not performance oriented Relatively poor flow (compared to an EQ) Valvejob is way undersized The goal here is to give these a performance oriented valve job with basic bowl blending using stock Magnum valves 1.92"/1.62" and achieve a good balance of flow vs. cost (time and or money). While flow is important, it is also important to identify and not lose sight of the intended use with 347 cubic inches in mind. Here are a few pics and preliminary flow numbers.