If I end up using that one, it won't need to be modified. I had it on a 318 in a 71 Challenger years ago and it fit just fine. The bolt holes got ratted out enough to fit way before I ever got it. I'm leaning more towards the Weiand anyway, because it's a spread bore intake and I'm probably gonna use a 72 Thermoquad I got from @GTX JOHN .