Reher-Morrison Racing Engines' David Reher and Darin Morgan answer your questions about cylinder heads or anything else concerning your racing engine building problems. Remember who you're are dealing with so no soft-ball questions.
4/10/06
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Steve,
The chirp people here at idle from high compression racing engines can be eliminated by simply changing the header design. Some headers broadcast that sound better than others. The chirping sound is one of those strange anomalies that take place primarily on large high compression drag racing engines. Whether or not an engine has the chirping sound has no real world correlation as to the amount of power the engine can produce or whether or not the cam design is correct for the engine combination.
As for the cam situation, an .800 lift cam is not considered “large” by today’s standards. With conventional style heads like the Dart 355CNC Pro1’s we routinely install .800 to .850 lift cams ranging from 282°to 286°@.050 in engines ranging from 540 to 622cid. With Larger spread port heads like the RMRE 12°Raptor the normal cam is .878 lift with 286°@.050 and the high end camshafts have .960-1.050 lift with 286°-288°@.050. All of these engines range in RPM 5800rpm to 7800rpm so the answer to your question is, No, the cams are not mismatched for the engine. As for your other question on turning a 540 or a 588 to 8500rpm, I would have to say that twisting a 540 or a 588 to 8500rpm with conventional heads would be an uncommon practice but it’s not out of the realm of reality.
Here at Reher Morrison we have built many 555-565cid engines that turn up to 8500rpm with conventional heads. Again, this is not the norm and the induction system has to be every efficient to operate the engine that high but again, it can and is being done. Turning a 588 to 8500rpm with conventional heads however, is a different story. With conventional heads a 588 just isn’t efficient at 8000+rpm but with spread port style heads 8000rpm would be quite normal. Bottom line here is yes, you can turn both a 540 and a 588 to 8000 or even 8500rpm+ but you have to have some very large cams and some high flowing, high velocity and very efficient cylinder heads in order to achieve power that high in the RPM range.
David Reher asked Darin Morgan to answer this question because it is his area of expertise.
Reher-Morrison Racing Engines
1120 Enterprise Place
Arlington Texas 76001
817-467-7171
FAX-468-3147
Visit our web site at http://www.rehermorrison.com
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