Iron Heads
 

Hi, Has Anyone Used Dart Iron Eagles On 540 Motors Naturally Aspirated. Are They Better Than The Merlin Vr And Protopline. Thanks For Any Reply

Re: Iron Heads
 

The Dart iron eagle heads are superior to the Merlins. The Toplines are a knock off of the Darts so they should be OK but I never flowed them. Ported, the Iron Dart heads will flow the same as the ported aluminum heads.

Re: Iron Heads
 

Jim- I was hoping you could address a few issues with using the Iron eagles on a 502MPI.
- what is the best way to handle the leaky valve cover problem?
- I understand that the intake valves are longer and the ex.rocker studs are longer. Do I need taller valve covers?
- because the intake valves are longer, will the installed spring height be different than the stock spring height and if so, do I need different springs?
thanks-

Re: Iron Heads
 

I would start with the 308's. Extra flow can be achieved with port work if needed. I use a cork or rubberized cork with no leaks. The thicker ones will gain some extra clearance if needed.

They should work using the stock valve covers. You will have to grind the tabs down inside the covers and some of the rail if your using the 500 hp style covers. In some cases you may have to shorten the K-nuts for clearance. I do this on a lathe, around 1/4". With a hydraulic roller, I use a 930 comp spring installed at 1.900. The spring heights shouldn't change unless your using the stock valves, then the installed height will be shorter. Somtimes you can use a +.050 keeper to help, but check your rocker arm to retainer clearance. With the longer valves, you should be OK.

Re: Iron Heads
 

Aluminum valve covers spacers in 1.125" height are available if needed.

Chris

Re: Iron Heads
 

Thanks Jim V . Anyone Have Any Other Comments.

Re: Iron Heads
 

Thanks Jim- Can you please clarify....When you say "grind the tabs down", are you refering to the oil dripper tabs on the top of the valve cover or the spacer tabs on the rail of the cover? I have 502MPI covers, not 500HP(I didn't know there was a difference other than the blue paint??). Will the flat cork gaskets work with the o ring style rail? Do I remove the o ring first? I will be using crane gold rockers...when you say grind the "k-nuts" are you refering to the poly locks? Will the comp 929 springs hold up as well as the Isky 9000 endurance springs?
Thanks again for the help-

Re: Iron Heads
 

Sorry , yes, the dripper tabs may have to be removed(check clearance first). If your changing to roller rockers from stamped I'm sure they will need to be removed. The covers are problaby the same 502mpi/500 hp. Yes, remove the o-ring.
Yes, I meant polylocks.
I haven't done any endurance testing with the 929's so I can't answer. I'm sure the iskys will work fine.
The rail will have to be modified at the ends of the cover to clear the head for proper fit. Also the tabs will have to be cut flush. You can use a die grinder for mods. The o-ring groove makes a nice reciever where the gasket will form to. Good luck!

Re: Iron Heads
 

Thanks for your help Jim-

Re: Iron Heads
 

Nooooooooooo problem, i'm glad you asked about the tabs I forgot they had to be modified.

Re: Iron Heads
 

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

Re: Iron Heads
 

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.

Re: Iron Heads
 

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

Re: Iron Heads
 

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

Re: Iron Heads
 

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

Re: Iron Heads
 

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.

Re: Iron Heads
 

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