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Most of these companies are using SI Severe duty stainless valves. They are a one piece design and actually are very good quality although imports. Personally I would take German stainless and machining over the good old sold in the USA (but in many cases now manufactured in Mexico thanks to Nafta and extreme low labor costs) These valves are available to the public from CP. I have had no valve failures in 10 years or running them. Most also do spend the money for Comp cams springs this is not a place to skimp or try to save money.
Competition Products (http://www.primediapowerpages.com/cg...titionproducts)
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It is always nice to build a set yourself.
Not sure if you benefit financially unless you are shooting for Serious RPM's that require lightweight components. Either to not float the valves/beat the seats up or let the springs live as long as possible in an offshore or poker run type boat application.
Peace of mind is priceless. ;) ;)
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Most of these companies are using SI Severe duty stainless valves. They are a one piece design and actually are very good quality although imports. Personally I would take German stainless and machining over the good old sold in the USA (but in many cases now manufactured in Mexico thanks to Nafta and extreme low labor costs) These valves are available to the public from CP. I have had no valve failures in 10 years or running them. Most also do spend the money for Comp cams springs this is not a place to skimp or try to save money.
Competition Products (http://www.primediapowerpages.com/cg...titionproducts)
I bought a set of Canfields from CP and their "import" severe duty valves. Sent the valves back. Margins were all over the place, seat widths varied .020. NOT impressed. Bought Manley's. The CP valves would probably hold up OK, I just require more in a precision part. I never did mic the stems. I would bet they varied as well.
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Just sort of answered the same question on another post...The AFR's seem to be the consensus as far as out of the box CNC head. I like the Canfields, especially for the money, but even so, would buy them over the Darts, money aside. The Brodix are fine...no complaints...buy them over the darts, too. Edelbrocks...naw. Pro Topline, ditto earlier post. Poor quality, lousy ex port. Big flow no's don't mean squat.
The main thing is, no matter what you buy, CHECK THE GUIDE CLEARANCES. If your machinist dosen't have the equipment to do this, fins someone who does. It's the most overlooked (haven't heard it mentioned by anyone in two different posts about heads) and one of the most important things about properly set up heads. Dis assemble them if you buy them assembled, and check your installed height, guide clearance, valve job, etc. Check for flaws, machining "crap" in the threaded holes and water passages, stuff like that. Just take a little time and look at them. Better yet, buy them un assembled, and learn how heads are supposed to be assembled CORRECTLY! Making a head and getting it out the door is one thing. Making a head that's put together right and will work correctly is entirely a different story. There's a lot of engines out there making decent power with crappy heads on them...most of them bought assembled, and run that way. You say " my heads are fine, no troubles for(?) runs or seasons? If you never took them apart and checked them, I would venture to say they could even be better!!
just my .02
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Hey D Thorpe
Lookie Here!!!!!!!!!!! :coffeycup
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Edelbrock has a new marine head for the big chevy.
Marine-Duty Performer RPM 454-O and 454-R
Designed for 396-502 c.i.d. big-block Chevy engines, these heads include heavy-duty, 1.89" Inconel exhaust valves that provide the added durability needed for marine applications and have one-piece stainless steel 2.25" intake valves with hardened tips and swirl-polished heads. The high-velocity flow capabilities of Edelbrock Performer RPM cylinder heads provide increased torque across a wide rpm range thatÂ’s ideal for marine use. Cast from A356 aluminum and heat-treated to T6 specs. The oval-port heads have 110cc chambers and the rectangular port heads have 118cc chambers. Both the oval and rectangular port heads are hard anodized to protect the aluminum in the harsh marine environment. Edelbrock big-block Chevy marine heads are sold with seals and valves only for a variety of combinations. Match with an Edelbrock Performer RPM manifold, Performer Series 750 cfm or 800 cfm carb and Performer RPM cam for proven performance.
Performer RPM 454-O Marine oval port
Chamber Size Bare (single) Complete (single)
110cc N/A #61459*
Performer RPM 454-R Marine Rectangular port
118cc N/A #61559*
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We've had very good luck with Big Brodies on race motors in the past, but when I started my stroker BBC project I wanted something a little better suited to mid-range RPM use. The AFR marine heads are nothing short of awesome, but when I called they said I was looking at a 2-3 month wait. So... I passed. Last I checked Pro Topline suffers from mediocre quality, and I think they may have gone out of business or been bought out. So... after talking with my head guy I ended up picking up a set of Canfield rectangle port heads, and had him swap the valves out with new Manley Inconel 2.25 and 1.88s, as well as a full port and polish. He mostly blended the bowls and did some shaping in the exhuast ports, and they cleaned up really nice. His opionion was that if I couldn't wait for the AFRs, a ported set of Canfields or Edelbrocks are just as good. The motor goes on the dyno in a couple of weeks, so we'll see how they do.
Dan
P.S.
Holley also offers rectangle port aluminum heads that are identical to the canfields, so if you can get a better deal on those, they're just as good!
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Just sort of answered the same question on another post...The AFR's seem to be the consensus as far as out of the box CNC head. I like the Canfields, especially for the money, but even so, would buy them over the Darts, money aside. The Brodix are fine...no complaints...buy them over the darts, too. Edelbrocks...naw. Pro Topline, ditto earlier post. Poor quality, lousy ex port. Big flow no's don't mean squat.
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Here's a little AFR/Dart comparison for ya.
Motor 1: 598, 10.7:1, Dart 355 CNC Pro-1 heads, mech roller cam, Dart single plane intake, EFI
Motor 2: 598, 10:1, AFR 357 CNC heads, mech roller cam (within a couple degrees of same specs as #1), same intake, Dominator carb
Both motors made about the same peak torque. For some reason motor #1 made about 40 more hp upstairs, probably due to compression and cam difference. Until someone shows me a back to back test on the same motor, same dyno, where Darts were pulled off, AFRs bolted on, and the motor made more power, my opinion is that the two heads are too close to call. The Darts on #1 have over 100 hours on them now, no issues.