500 HP Racing Engine For $2,500 - Is It Possible?

Cost and race classes that call for "as cast" iron heads are the driving forces behind the production of the heads you see here. Fierce competition has brought about the development of cylinder heads that, in "as cast" form, would have at least matched the heads seen on most cost-is-no-object Cup engines of just 25 years ago. The three types of heads we are featuring here have all, during our dyno testing, proven to be very strong performers when used with an appropriate combination of compression, cam, valvetrain and induction.

For a shade under 500 bucks, bare, these heads are a great deal. The casting finish is not quite as good as the other two brands of heads featured here. That said, we have run both the 180 and 200 cc versions in "as cast" form and seen outstanding results on the dyno. There have been more than the odd one or two pro engine builders who have lost bets by underestimating the power production capability of these heads. In addition to being good out of the box, these heads port up easily (we have seen 300 CFM on the intake and 207 on the exhaust at just 0.600 lift) and can be done by a rank beginner over a weekend. In the relatively short time they have been available, these heads have been showing championship winning form on many circle tracks.

The Platinum series of the Iron Eagle heads from Dart is the result of the wet flow technology introduced late last year. Our tests have shown this technology to be worth over 20 hp on a nominally 480 hp test engine. These heads are now just showing their potential. Like the other two head designs featured here, these heads port up very easily. Just optimizing the original Dart port form on a 230cc port (2.08 valve) head and adding a Cup-style seat job resulted in 315 for the intake and 223 cfm for the exhaust at 0.700 (seven hundred thousandths) lift. To put those figures into perspective given the cam, compression and induction, that's more than enough airflow to top the 600 hp mark.

Experience with just one set of these heads on the dyno involving a cam testing session showed great potential, to the extent re-visiting them was made a high priority. Although the combination tested was a little off optimal in terms of induction (it was not our engine), results were still excellent. And excellent in this context means race winning capability. Such results were not of any great surprise here as the current design of the chambers and ports on these heads is the result of about 10 years of development. The casting quality on the pair of heads currently in our shop being readied for an engine is among the best seen to date.