I'm just the 'pee-on' over here when it comes to decisions on the Roadrunner & Charger. My son makes the decisions and then I get to mock him for them as I'm working on the cars.
The last word I got was a GO on the head swap.
Mike at MRL has been giving advice on the component selection for the Charger's 512 build. Many of the parts we'd accumulated for it were based on a restricted budget. Now that my son has decided to open up his pocketbook even farther, some of the components are being re-purposed on the Roadrunner.
When discussing the build with Mike he asked me what the horsepower goal was. I told him my son was shooting for as close to 1000 as he could get. After a second or two delay over the phone he asked me 'Why so much?'. Although I couldn't say for certain I told him that up to now I was winning the HP battle over here with the 440 in the Duster and the 408 in the 'Cuda. Spencer's 383 Roadrunner and 6.1 Challenger seemed mild in comparison. I felt that he didn't simply want to be faster than me. He most likely wanted to be able to totally annihilate me.
I'm not too worried. - I've still got the funnycar and it will weigh only half as much.