My dad has been racing since the late 50's and I have been into cars since I was little, so all we know is testing and racing.
Dyno's are great for testing, but until you get the engine in a car and at the track, its all for bragging rights. I have seen first hand 500 hp dyno engines run slower times then stock engines due to the power band used to get the 500 hp. Same with large cfm heads, most cars slow down or loose ET if not done right.
We spent an entire day at the track just test intake manifolds on dads Pontiac, 13 of them. Each one was run twice. His station wagon will repeat times with in a few thousands each run, 11.41@117, at 4100 lbs it doesn't spin the tires. We can tell even the slightest change in performance due to the consistency. We still got grief because we didn't change the carb or cam or what ever to make one run better then the other. Our point was to test against each other in the same weather and on the same engine at the same track. Theres no arguing about it!
This is the same system we used to check mufflers, two runs each along with a sound meter. Again guys bitched because the runs were not altered to help one or the other.
This is what needs done with the heads. Flow bench numbers don't mean squat if it won't run at the track. I am not talking about all out 8000 rpm race engines. Bolt them to a everyday car with mild up grades (average Joe's) and see what 300 cfm does to a engine. I'm betting there isn't going to be much difference in any of the three types on a mild engine.
What it does come down to easy of installation and fit. The average machine shop probably hasn't seen a inline 6 in a lot of years, let alone built one, so adding lumps isn't going to be a job for anyone except a custom engine builder or hands on type of guy. The guy that repairs Honda cylinder heads is not going to like adding poorly fitting lumps!
And when I hear things like, "you have to know where to cut", it just makes me mad! Why should this be such a secret that you can not show it or explain it, why bother bringing it up other then to brag about it. That right up there with cam grinds to secret to tell, "just buy it and you will be happy". Don't waist our time with out data to back it up, racing with out time slips is meaningless. If you know something but are unwilling to tell about it, just keep quite or send a private note and talk off board.
Sorry about getting off track, but come on, does every post have to get into the same arguments?
Joe
