Guys and Gals, I had my 72 440 redone with a bump in cam and mild compression. This done by a guy that's been doing RB engines for the local muscle crowd for at least 30 years. http://imperialclub.com/Yr/1972/Wills/ I told him to do what he thought best for my project, a GT, or Grand Touring car without doing the research, debate, or reading like so many of my car brothers seem to. I don't think that there was any major change in the heads, although the rust in the "been sitting" engine cylinders required it to go 40 over. Result: The engine is peppy, but not really all that different from stock. My 100k 1973 is maybe 5%-10% down on power by comparison at the most. I presume that a totally stock rebuild would close at least 50% of whatever gap there is, so I figure that the cam and pistons and whatnot were at most a 5% gain. I do notice that the car is incredibly thirsty and gets horrible gas mileage, probably in direct opposite proportion to however more powerful it is than it was in stock trim. After the engine was done and had been driven for a little bit, I removed the really nice $225 edelbrock performance intake manifold and replaced it with the stock one when the hood would not clear the air cleaner. Guess what? No discernable difference, although I'm sure I could show one on a chart somehow if I cared. This leads me to conclude that I wasted $225 and two hours of my life on that intake manifold... Also makes me wonder what else was a loser that sucked up money. Like the deep oil pan that didn't fit or the stupid chrome air cleaner.... ---- This discussion about heads and engines and all that makes me mentally cringe at the amount of energy spent over the last 50 years by couch-racers trying to navigate changes to already really good Chrysler designs. The Imperial is 5000 pounds for crying out loud. And it's NOT a GM or Ford product! A bump on the cam and new valves/rings will make the biggest difference. Spending "a lot" of time or money on swapping out heads and all that other stuff is a bunch of hooey in my opinion, with all due respect to the folks here and elsewhere that feel otherwise. As I was selling the 150 RB (imperial) engines that were down at Doc's place to the general public via online ads, I listened to all manner of BS from people spending all sorts of time decoding casting numbers on heads and blocks and looking in books and trying to make sure they were getting a "good" 440 engine. Many of them turned their noses up at the post 1971 (or was it 1970?) 440's because the crank went from forged to cast or vice-versa - I can't recall (and don't care). Since so many of the muscle-heads were raving about this and the 915 heads that just plain weren't on the property (and I had two people ask permission to flip through about 40 heads just to be sure even after I'd said we had none), I asked around about it regarding doing a street rebuild on a 440 and how much of a difference stuff like that makes to the finished product. The answer that I got from people I respect that rebuild Mopar and have experience was that the "better" crank made a difference in engines built to perform at the top 10% of the envelope, above 600 HP or something like that. The kinds that would be used for drag racing or whatever extreme applications, and not in a street car. Do you have any idea how much it takes to go from 400 to 600 HP on a 440? These engines I was selling were all going into street cars. Not one imperial owner, all Barracudas and Challengers and that sort of thing, and those folks are certainly focused differently than the Imperial people that I've met over the years, so I can take that into account regarding mindset when shopping and all that. Yet most of these "clients" were raving about 915 heads and Pre-1971 440's and so forth, repeating most of the stuff they'd read on forums and in the various publications that focus on that sort of thing. Best I can tell: It does not matter for the most part. Someone needs to sell magazines and engine rebuild books, so they need SOMETHING to write about, and these differences are factual differences in the engines. People seem to bypass the common sense fact that the "better" aspects of these parts only benefit you for specific hi-perf applications. Just like giant tubs with huge slick tires in the rear would. Over the years, this forum has had all manner of messages about upgrading and modifying the original engineering on our cars. Seems that there is a recessive gene in men that activates and cries out to "MAKE IT BETTER" when working on a car. I'll tell you that for all the things that I've done to change that 1972 around, I've had at least 50% of the changes go sour or require additional "engineering" to correct for the changes. Since I'm a schlub, you could argue that a better researched project might have perhaps only a 25% failure rate or maybe none at all, but that's STILL a high amount of problems that wouldn't be there if I'd just stuck with stock, something that I went back to stock most times and had no more problems without any real degradation in performance that I could tell. SO: That's the last time I'll mention anything about it here, since I don't want to burst anyone's baloons or be a dreamkiller, but I think that most of the High Performance engine discussion stuff offers some pretty marginal ROI, especially considering how much research, debate, and energy some of these messages seem to have behind them. I can say it's better to spend energy memorizing engine specs than baseball statistics, the other use that men have for that part of the brain.... Oh, and pre 1967 cars should NOT have discs or radial tires on them, since they worked great when fitted with correct parts when new, so there. Have a nice day. Kenyon Wills ____________________________________________________________________________________ Looking for last minute shopping deals? Find them fast with Yahoo! 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