Jim V
I have two older set of merlin cast Iron heads they are actually off a boat that was from Michigan a old 32 hustler with arnesons formally the
Savage. I believe they were ferrera motors 540,s . They have had very extensive bowl work and port work. However no flow #s available. I actually called you before I had them off. Not realizing they were done already.Given your experience what benefits would be gained by going to a AFR or dart pro ones. Blown application
Cigarette39 sorry for hijacking this thread.

Thanks in advanced
Gerry

The Darts and AFR's (both being ported) will flow more air hands down. The Merlins are outdated. The old square port exhaust even more. If you choose the CNC AFR heads the chambers and exhaust ports will have to be reported to match the airflow of the ported Darts.

Jim V, have you ported any AFR exhausts? Do you think they can be modified to flow as much as the Darts?

Yes sir, with chamber and exhaust porting, the AFR's will flow as much air as the Dart's.

I would also look at Canfields as an option. The BBC head was designed by HVH, same guy who designed Brodix's intake manifolds, and has killer exhaust out of the box. The head is also available in hard anodized finish. Low to mid range on these is killer.

Any aftermarket cylinder head company is constantly improving designs. One thing I take into consideration is that when a head flows good low and midrange numbers then it will take milder cam to make power. This will add to longevity and reliability in the engine due to the fact the valvetrain doesn't have to experience radical ramp and flank rates to compensate for poor flowing heads.

Chris

In all due respect to Chris and Canfield heads, the exhaust ports are soft in the midlift area due to the lack of short turn radius. They flow excellent at higher lifts. The airflow keeps comming after .700 and well beyond .800.

It would be interesting though to dyno (or flow test) both sets against each other after some run time. All exhaust ports lose airflow because of carbon build up. I'm wondering if the canfields would not fall off because of the port design.

Jim,
Somewhat yes, but in the hands of a good porter you must some work to do so "reshaping" can occur. Joe has always said that with about an hours worth of work on a set of head's exhaust ports you can achieve what you need. I personally have been apart of several projects using them and have always made good power.
BTW, thanks for your time. I did what we discussed so you should have something soon.

Chris