MLS gaskets are made with thin sandwich of stainless steel, stainless is very tough but is so hard it will not conform to any irregularities, hence the need for a 50ra surface finish. Back in the day we used single layer steel gaskets coated with aluminum paint, or cooper coat, the paint and copper coat was there to fill small surface irregularities. The best old school gaskets are copper, copper is soft and conforms, and then with heat, work hardens and gets tough. I believe top fuel still uses them, so since money for gaskets is not an issue, they must be good right? composition gaskets like say a fel pro seal great, but may give it up over time, ask any mechanic working on cars in the 80's and 90's how many head gaskets they installed. Most of which failed just about the 150,000 mile mark. They helped me raise my family.
My experience is that for a normally aspirated engine, if you don't have the correct surface finish for MLR gaskets, a composition gasket works fine, used many of them up to 14 to 1 compression, and never had an issue. The only engines I have ever had a problem with head gaskets on a performance engine were the ones that only have four bolts per cylinder, like a 340 LA for example, they get a copper gasket with a o-ring in the block, with high compression. The guys that hop up diesel's what do they use? they dump the MLR gasket and use a copper gasket with a fire ring installed. At least the truck pullers around here do.
Gasket companies went to MLR gaskets because of issues with OEM engines, 20 years ago, so that is the technology they are using, which may or may not be what you need with an older performance muscle car engine.