I run the steel core Fel-Pro's. Absolutely no issues even with blazing EGT's that high boost and a low timing pump gas tune produce. I retorque them after the first two heat cycles (they barely move) and they don't move after that.
Never had good luck with the Pearcy's aluminum gaskets or the copper ones, tried them in the past. Been using the Fel-Pro's for about 3 years now with very good results. I use their steel core collector gaskets too.
__________________
1969 Chevelle
Old setup: Procharged/intercooled/EFI 353 SBC, TKO, ATS/SPC/Global West suspension, C6 brakes & hydroboost.
In progress: LS2, 3.0 Whipple, T56 Magnum, torque arm & watts link, Wilwood Aero6/4 brakes, Mk60 ABS, Vaporworx, floater 9" rear, etc.
Earl's Pressure Master header seals. Aluminum frame, soft aluminum seal insert. I never had a leak in three years+ running them. I had to check torque once after installing them, and only one bolt was even the slightest bit loose. I do have to admit that I may have forgotten that one the first time though. That and they look cool installed.