Subject: Re: Engine Dyno Predictions: by BeachBum on 2008/12/26 19:51:35
Quote:
1989GTA wrote: Some interesting comments in this thread. I want to thank the original poster for the time and effort that went into this test. Also the Dart heads did have a bigger intake runner.
1. "25 lousy horsepower". I think most people would think that is a pretty good gain for heads that are virtually the same cost.
2. "If the Dart heads were lightly ported". Could that not also go for the AFR heads?
3."But the 20hp cost $1000". I have no idea where that number comes from. Looks like someone just pulled that out of their your know what.
The Darts heads had runners that were optimized using their "wet flow" technology. The AFR heads were digitized after the initial hand porting by Tony. Hence the CNC to follow that pattern as close as posible. The camel hump heads were fully hand ported and a good job at that.
It looks to me that each head was maximized using what technology the manufacture felt was best to achieve their goals. Just because a head was CNC'd means nothing. It is the final shape of the port that counts.
I agree with the above, and speaking for myself, its hard to find a 25 HP difference between two aftermarket choices that cost the same.... it really is.
Its been suggested that perhaps this set-up was somehow slanted towards working favorably for the AFR 195's, but to tell you the truth, I think you could have a big motor, small motor, carb motor, efi motor, 5000 rpm motor, 7000 rpm motor, green motor, pink motor with purple polka dots..... it wouldn't matter, I am not aware of a single motor situation that the Dart Platinum 200 cc Pro-1 cylinder head would outperform the AFR 195's.
In otherwords, what situation would the Darts outperform the AFR's ? I really do not know, and would be interested in hearing any opinions on the subject.
On another note, the 195 port is used a lot for one simple reason, its the midsize street type runner size, excellent runner size for the guys who are building a semi-rowdy 350, perfect size for the 383 and even a good runner size for the 406-421 street/strip set-ups staying under 7000 rpm. The above pretty much covers 95% of C4 related build-ups and might be why you see the cylinder head utilized so often. But, the 180's, 210's & 227's pretty much fill-up any street/strip voids left.....that is, if you like AFR's.
