Ok, here's the info from speedtalk and Joe:
"I worked at Edelbrock back in the good old days, When they made that manifold(tr-2x) <span style="font-weight: bold">the first ones had the good port/badd port layout with smaller ports on the good runner in the heads,</span> Anyway, they only made one run of those good manifolds, then they changed the design so all the runners were the same. The good one ( only 50 were made) were 30 Hp better than any other tunnel rams they have ever made. I take it the one you have is the one with all the runners the same size.. On an 900 HP 540 I did, when I went from one1150 carb to the tunnelram with two 1050 carbs, the engine PICKEDUP 100 HP with NO other changes. Back in 1971, It was worth 70 HP on a good 454(750 HP back then)
JOE SHERMAN RACING ENGINES
Check out this thread over there as there's alot of info on old tunnel rams:
http://speedtalk.com/forum/viewtopic...t=tr2x#p213133
Just some info to help you guys out!