The 318/360 Performer can be port matched about an inch or so deep to a 340/360 sized gasket. Even then, it's only a few HP better than a stock '71 or '72 340 intake.
I found that same issue with the Performer I put on my 351W MoFoCo. Just not that much better than the iron I took off of it. Sure wasn't the Torker I put on my 289 previous to that. That 289 was an animal! :steering: