I'm aware what a OEM flexplate is.... lol... The weight welded in the arch would actually strengthen the stock flexplate I'd think. The guy I have balance them will build you a 1400 hp monster truck motor or a 95 hp smooth running 6 banger. The one I'm currently running has been behind 2 360's over the span of about 12 years. Maybe 15 yrs, I can't remember... LOL