Phenolic spacers, ported or open?
What intake are you using?
These aren’t phenolic but they did start life as 4-hole ported spacers until I opened them up. I still wanted to retain the split plenum feature of the dual plane intake so I left the divider intact. Eventually, I’ll do the same to a set of phenolic spacers to stop the heat soak that we all know these carbs are known for. It’s actually kinda hard to find phenolic spacers that have both carb bolt patterns like mine shown in the photos but Trans-Dapt makes them . . . expensive, but they make them. BTW, check out that gasket mismatch that needed some re-work!View attachment 68114View attachment 68115
They work pretty well.Jim.Just as another option, Edelbrock makes 3/8" thick gaskets to help with the heat soak problem. Don't know how they compare to the phenolic spacers for heat protection.
Just to add, I'd advise against the plastic ones. I was given a pair of them. The fit wasn't great and on top of them cracking, the carb butterflies would catch on the holes, preventing the throttle from completely releasing. Pure junk.