What would YOU do? - Chevelle Tech
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post #1 of 19 (permalink) Old Mar 25th, 20, 5:04 AM Thread Starter
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What would YOU do?

So being interested in a possible purchase of the fairly new Brodix BBC cylinder head model, called thier "DragonSalyer" heads, I began searching the net for actual specific pics for the combustion chambers of these particular heads, since the pics on the Brodix site seem to be generic, and the same for almost every BBC head they sell. I finally found a video of a vendor participating in last year's PRI show who had these DragonSlayer heads on display. I was also able to obtain a few pics of the actual chambers, (shown here).

I cannot say that I've ever seen chambers like these, with only part of them having a machined surface, with the remainder of the chamber surface being left as cast. But my brief experience with Chevy heads is with AFR heads,and iron OE heads, so that's all I have to compare with these Dragonslayer pics. At first I thought that it would be best for the end users running pump gas to hand polish the cast surface areas of the chambers of these heads, to avoid hot spots and detonating. But then I thought that many OE type iron heads have the entire chamber surface cast, correct? And furthermore, the entire chamber surface, be it machined or cast will have a layer of carbon covering it after just ten passes, or 10 miles of highway use anyway. So it probably won't matter if the surface is cast or machined.

So if you were to purchase heads with chambers like these out of the box, would you leave them as is, or would you hand polish the casted areas of the chambers with a power tool? I just never saw aluminum heads having chamber surfaces like this before, so that kinda threw me off. Dropping enough coin for new cylinder heads isn't something I do more than once a decade, so I don't take it lightly.
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70 Chevelle SS clone (632 CI powered).
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post #2 of 19 (permalink) Old Mar 25th, 20, 6:21 AM
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Re: What would YOU do?

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Originally Posted by BillyGman View Post
And furthermore, the entire chamber surface, be it machined or cast will have a layer of carbon covering it after just ten passes, or 10 miles of highway use anyway. So it probably won't matter if the surface is cast or machined.
I might polish them just due to bad habit. But I agree with your comment about a street head. Its only a matter of time before its not shiny inside.

They may have left it bare for final CC'ing of the chambers? For those who actually blueprint.

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post #3 of 19 (permalink) Old Mar 25th, 20, 7:44 AM
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I would leave it alone.
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post #4 of 19 (permalink) Old Mar 25th, 20, 8:32 AM
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Re: What would YOU do?

I could be way off here, but I would think a polished surface would retain the heat better than an "as cast" surface and heat retention with an aluminum head would be a good thing.
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post #5 of 19 (permalink) Old Mar 25th, 20, 9:24 AM
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Re: What would YOU do?

Billy sir. From what i have been told and seen on the internet you would be better off with the promaxx or flotek 315 317 heads. They would probably be just as good as the dragon slayer heads for less money. Also on the surface picture. You are better off to polish the rough cast area. If your engine is carboned up that fast you definitely have a problem somewhere. My 427 ran all year with carbon build up on piston chamber runner. They actually look like the fuel polished it some. But only have a season on it. Now as for the rough chamber. Think of it like a piston you polish off the small sharp edges to eliminate hot spots. So the rough cast is just many a little sharp edge hot spots waiting to happen. Smooth it to the rest of the chamber.

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post #6 of 19 (permalink) Old Mar 25th, 20, 9:32 AM
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Re: What would YOU do?

I like 'em a bit smoother (waxed, actually) but one other thing to consider is coatings. It depends largely on how much heat rejection you're looking for and how close you are on the tune if you're going to be pushing it with compression.
I've never had the opportunity to check out polished chambers after 30K or 40K miles but I have taken heads off of 250K mile engines with no visible carbon build-up anywhere, so I dunno.
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post #7 of 19 (permalink) Old Mar 25th, 20, 10:22 AM
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Re: What would YOU do?

Billy,
Unless you are going to CC them I would leave them alone. Any material taken out will increase the chamber volume decreasing compression slightly.
My last set of new Brodie heads BB2 plus -I had .005 flat milled off the head. Then I ccd all the combustion chambers to 118 CC. I also did port work.
As an example.. difference between an extended plug and a standard plug changes the chamber volume by 1/2 cc.
FWIW I really like the flow numbers on those Dragon Slayer heads!

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post #8 of 19 (permalink) Old Mar 25th, 20, 10:23 AM
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Re: What would YOU do?

wouldn't worry about it. my AFR305 are the old 'as-cast' chambers(2005era). they have less machining than those heads in the pictures, it was by no means a detriment.

I do agree though after recently having them off again I found myself wanting to do a fluff and buff. But why bother, they have worked this far.
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post #9 of 19 (permalink) Old Mar 25th, 20, 10:38 AM
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Re: What would YOU do?

Me, I would take a burr and hit the spot that are already polished and rough them up in that area. Polishing the chamber does nothing but cause fuel drop out. I do the same thing on intake ports.


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post #10 of 19 (permalink) Old Mar 25th, 20, 11:11 AM Thread Starter
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Re: What would YOU do?

Thanks for everyone input. Exactly what I was looking for. Many of you have brought up some good points IMO. Oh, and about the fuel drop out being possibly worse with smooth chambers, that's what I was thinking too. Like Ray said, I think I would just leave them alone if I pulled the trigger on a pair of these. I just wanted everyone's input since I've never seen chambers left like that before.

Thanks again guys.

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post #11 of 19 (permalink) Old Mar 25th, 20, 1:10 PM
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Re: What would YOU do?

Are you going with a 2.300 intake valve? I can't remember what RPM range you wanted, and how "spirited" you wanted to get

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post #12 of 19 (permalink) Old Mar 25th, 20, 1:55 PM
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Re: What would YOU do?

The Brodix heads I have used was avaible with cnc chambers as option maybe the dragonslayer heads are too? Check with Mike Lewis.

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post #13 of 19 (permalink) Old Mar 25th, 20, 3:30 PM
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Re: What would YOU do?

Quote:
Originally Posted by 68Chevele View Post
Me, I would take a burr and hit the spot that are already polished and rough them up in that area. Polishing the chamber does nothing but cause fuel drop out. I do the same thing on intake ports.
I stopped polishing chambers, bad habit I guess. Probably run the same either way...intake ports on my own stuff I never even use a roll anymore, carbide is enough.If youre doing it for someone else they will never get it they associate a pretty roll job with "good port job" it just aint so.
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post #14 of 19 (permalink) Old Mar 25th, 20, 7:27 PM Thread Starter
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Re: What would YOU do?

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Originally Posted by aukai View Post
Are you going with a 2.300 intake valve? I can't remember what RPM range you wanted, and how "spirited" you wanted to get
with the dragonslayer heads, you only have two choices, 320cc ports with 2.25" valves, or 365cc ports with 2.30" valves. Since the former would be waaaaay too small for a 632cid build, I would choose the latter. As Mr. Foxwell advised me, 2.37" valves are the ideal for a 632 mill, but since I'm planning on keeping the RPM below 6,500 I'm willing to compromise with 2.30" valves. Especially since the two intake manifolds I've chosen to play with, (ie. The BMP "Merlin-X" single plane and the Edelbrock Super Victor TD 2916 ) are both very likely compromises above 6,000 RPM on a 632 engine anyway. So either manifold would undoubtadly be the weak link or the bottle neck holding back the power delivery even if I did decide to choose a head with a 2.4" or even a 2.35" intake valve.

But the intake manifold compromise is needed to contain this whole engine combination inside a OE type cowl induction hood that I have on my 70 Chevelle, while still being able to use a Dominator carb, with a 16" diameter, 3.5" tall air filter element and there is just no way I would cut a hole in that hood, nor choose one of those aftermarket fugly eye sores that are called a 4" or a 6" cowl hood since they just ruin the entire look of a classic car body style. IMO you might as well race or drive a 1980's Camaro, or Fox body mustang since they have ugly body styles anyway. But NOT on my Chevelle. I'd rather leave power on the table than slap one of those abortions on my Chevelle. Sorry for being so outspoken on that, but since this is my car we're talking about here, it's my right.

Quote:
Originally Posted by Malibu ss 64 View Post
The Brodix heads I have used was avaible with cnc chambers as option maybe the dragonslayer heads are too? Check with Mike Lewis.
I spoke to Mike Lewis, and the man gave me a better price quote on the Dragonslayer heads than you would ever find anywhere else, short of lucking out and finding a pair either new in the box that someone is selling for a song and a dance due to something like a job loss due to the corona virus hysteria, () or a set that is barely used at all being sold due to a similar hardship reason.

But anything short of lucking out like that, Mike Lewis is the man to go to for these, yes. But as far as what Brodix offers, you shouldn't have to pay extra for CNC chambers to have a set of heads with the entire chamber surface machined, because that is not the case with the rest of the brodix BBC heads. So I don't understand why it is with these dragonslayer offerings. They're a little less expensive, sure, but they're still not cheap by any standard. Just take a look at what Summit and jegs sells them for if you don't believe me on that. They're still more expensive than many of the edelbrock heads for instance as well as many of the Dart heads too.

Quote:
Originally Posted by cuisinartvette View Post
I stopped polishing chambers, bad habit I guess. Probably run the same either way.
Thanks for your insight on that. But have you ever seen or had BBC heads with chambers like those shown in the two pics I posted, with half the chamber surface still cast, and the other machined? I've never seen this before. Very strange.

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post #15 of 19 (permalink) Old Mar 26th, 20, 8:18 PM
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Re: What would YOU do?

My Brodix 294 RR-R with CNC option had a little of the same but not that much, maybe it's left for a reason ?
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