The pics I posted I believe are Allstar brand. I saw some other pics of a plastic type 1” with tapered 4-holes that was melted as well but can’t recall where I saw.
I had an Allstar 1" 4-hole spacer on my truck that melted after some miles. 360 with Performer intake but heat crossover blocked. I went to pull the carb and noticed there were DEEP indentations on the underside where it mated to the manifold and the gasket had melted into the plastic (tore off and left fibers behind embedded in the plastic). I left a bad review on Summit (long past the return/exchange time) then went to a local speed shop and got an Edelbrock one. Been doing fine ever since and that was about a year ago, maybe more.
I've used many plastic/phenolic spacers in the past but they were always Edelbrock or another quality brand that makes carbs/intakes, tried to cheap out that one time and it bit me!
I will say I've been running a 1/2" wood fiber spacer on my Duster for 4+ years now and it works great although last time I pulled the carb I noticed the spacer was a bit discolored where it's exposed to fuel. I do run regular E10 gas so the ethanol might have something to do with it but I'll keep an eye on it.
