real race mufflers
I've used Delta Flow Flowmaster on a bunch of cars went mid 8's @ near 160mph with a 3500lb RR with N20 using them, only picked up les than a couple of tenth's with out them, that was mainly because of the 100+lbs weight of the full exhaust, all the way out the back mostly... I used the Flowmaster from the beginning when the owner was a regular guy, supported the racing {from Santa Rosa Ca.} at the tracks at Sacramento & Sears Point mostly back in the 70's, when they were basically the only TRUE & REAL Racing chambered mufflers out on the market, that would stand up to big horse power & N20, without killing a ton of HP/TQ, like all the rest would... But if I was to do it again I would go with either the same 50 Series Delta Flow Flowmaster Racing Mufflers & 4-2-1 Scavenger race collectors {they are big/heavy}, but they actually create a vacuum, to help draw exhaust out the system on a flow bench at my old buddy Mark Lowe's shop, my old great cylinder head porter, may he rest in peace... {if they still even make them even, I have at least a 18+ year old ones on my 68 RR now, with new 3" mandrel bent Flowmaster tubes all the way out the back} or I would probably use the Dyna-Max straight thru type race mufflers, like suggested by Jim LaRoy/IQ52 or resident professional cylinder-head expert... see photos below
