HVH Super Sucker On 360 Magnum

There are a lot of "it depends". Carb size, jetting, intake, overall combo. I haven't done back-to-backs, but I run a phenolic version from Canton and like it. Anytime you change ANYTHING, you may have to change jetting and/or squirters to optimize the "combo". Typically, an open spacer would need more jet and squirt to make up for the extra plenum volume. A four-hole can increase signal strength, but it also increases plenum volume. A Super Sucker/tapered 4-hole is in between. Something to think about.