You could build it to stock specs. Then all you would have to do is find some 100 octane leaded fuel and you would be good to go.
Or you can take the advice of people who have been through all this and have a motor that has 50 more HP,runs on 89 octane unleaded and no over heating.
PS, open or closed chambers still 72 cc's (unless heads are62's then about 75 cc's)
You agree that a stock 400 will run great as it was built from the factory if you use fuel like was available back when they were built. It seems that these experts(no sarcasm, these are real experts)that you are quoting are talking about some blocks that have been machined improperly right from the factory. They speak of 'troubled 400's' and blocks that when they are built have the pistons 'more' than .030 in the hole. They aren't talking about 'ALL' the 400's, just troubled ones. Here is my thinking; I look at the two choices that you outline. Choice one is to keep my very stock car's engine just as it was in 69. Find higher octane fuel, which is available, and drive it like it's 1969. And it does run perfectly like that. No detonation or overheating. I would like to give an example of the performance which is hard to do without taking you for a ride. The best I can do to give you an idea of the performance in just a sentence would be to say that it will brake the tires loose when it hits each gear and it's an automatic. To me, it has just the right amount of horsepower for fun on a road course and for cruising. I've had a few 1st gens with 400-500 HP and they are a lot of fun but it's all overkill. They make a lot more noise and can do much more 'fun and obnoxious things'. Even after having quite a few 'altered to be fast' cars, I'm very happy with what a stock 400 car can do. Choice two would be to have around .020 milled off my original block that hasn't even been overbored. This would raise the compression so you will definitely have to relieve the heads to get the compression back down somewhat. Then I also would have to alter the stock cam profile. Their theory is that this will allow me to retard the timing to burn the crappy fuel.
8point, I know you have told us before but please tell us again; What compression are you running? If it's less than stock then what did you have to do to the heads to get there? Since you have a lively specimen, what gas do you use and how does the car run? If you are burning low octane fuel and have high compression, how do you know that you have no detonation? Since you have headers it may not be heard.
