What porting stage to get?

Author Topic: What porting stage to get?  (Read 793 times)

Offline IndyCuda

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What porting stage to get?
« on: March 10, 2010 - 09:06:11 PM »
I just found out the other day I am gonna be a daddy for the firs time!  :clapping: The wife is letting me finish the upgrades on the the cuda I had already started. I sent my heads off and would like any opinions on porting. I want he most bang for the buck but don't know much about it. The heads are factory iron J's. I was originally going with the stage 3 but will there be a big difference between 2 and 3?

Lunati Voodoo cam 60402

Cam Style      Hydraulic flat tappet
Basic Operating RPM Range      1,400-5,700
Intake Duration at 050 inch Lift      220
Exhaust Duration at 050 inch Lift      226
Duration at 050 inch Lift      220 int./226 exh.
Advertised Intake Duration      262
Advertised Exhaust Duration      268
Advertised Duration      262 int./268 exh.
Intake Valve Lift with Factory Rocker Arm Ratio      0.475 in.
Exhaust Valve Lift with Factory Rocker Arm Ratio      0.494 in.
Valve Lift with Factory Rocker Arm Ratio      0.475 int./0.494 exh. lift
Lobe Separation (degrees)      112

will be hooked to 2200 stall and 3.55 gears

STAGE 1 PORT WORK: $350
Details: Stage 1 porting consists of an intake and exhaust bowl blend. We hand blend the the bottom cut of the valve job to the bowls going approximately 1 ½”-2” down into the bowl. On the exhaust side this includes hand radiusing and ovaling of the exhaust seat area underneath the 45* seat angle. On the intake side we “chatter” the valve seat under the bottom 60* cut with a carbide to help break up the wetflow as it crosses the valve seat. The exhaust port will also get the short turn and ST corners radiused. The intake port will get gasket matched, and the pushrod pinch area will be opened up. The rest of the intake ports and exhaust ports will remain untouched, in as cast state. NO chamber work of any kind is performed.

STAGE 2 PORT WORK: $575
Details: Stage 2 porting consists of Stage 1, plus: Intake runner head bolt bulge will be eliminated, intake short turn will be radiused and widened slightly. Combustion chambers will be de-shrouded around the intake and exhaust valves, and sand rolled with 80 grit, for a smooth transition from seat to chamber. The backside of the chamber (non plug side) will remain untouched.  The rest of the intake runners and exhaust runners will remain AS CAST, with no blending/shaping or sand roll work performed.

STAGE 3 PORT WORK: $750
Details: Stage 3 porting consists of Stage 1 and 2, plus: Intake and exhaust runners will be fully blended/shaped, every inch of all ports/chambers will be touched with a carbide/sand rolled for maximum flow and surface finish. This is maximum flow port job we can do on a 2.02’ iron head.




Offline brads70

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Re: What porting stage to get?
« Reply #1 on: March 10, 2010 - 09:09:55 PM »
With all the aftermarket aluminum heads available now, I don't think I would spend very much/if any on stock heads? Just my  :2cents:
Brad
1970 Challenger 451stroker/4L60 auto OD
Barrie,Ontario,Canada
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Offline IndyCuda

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Re: What porting stage to get?
« Reply #2 on: March 10, 2010 - 09:23:44 PM »
I would agree but those are big dolla. Indys are pricey and Eddy's don't really flow out the box without porting. 750 or 18-1900 is a big swing. I can get 250+ with my J's for 750. I jus wonder how big of a difference. I heard you get the mos bang in the 1st stage.

Offline femtnmax

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Re: What porting stage to get?
« Reply #3 on: March 10, 2010 - 10:07:12 PM »
The most flow improvement is gained by working the area within about 1 inch on BOTH sides of the valve seats, so that includes port and combustion chamber work.  So the port work in stage 1 sounds good.
What would it cost to have your cylinder head guy unshroud the valves?  Its a basic operation:  scribe the head gasket cylinder openings on the deck surface of each head.  To be conservative set up the correct cutter to cut to within about 0.10 inch of the gasket scribe line, which leaves room for the head gasket combustion chamber metal sealing ring to flatten out without hanging over into the combustion chamber.  Once the cutter is set up, all 8 intake can be unshrouded.  Then set up cutter to do all 8 exhaust.
Maybe the cost is close to the extra $200 for stage 2, if so then stage 2 would be worth doing IMO.
Part of what helps the Edel RPM heads flow is unshrouding the valves.  When I did mine it added over 4cc to combustion chamber volume, so shows how badly the valves were shrouded.  I ended up milling the heads 0.010 inch to regain the lost compression due to the unshrouding cuts.
Phil

Offline 72cudamaan

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Re: What porting stage to get?
« Reply #4 on: March 10, 2010 - 10:25:20 PM »
With that small of a cam and low rpm usage, I wouldn't think you would see much if any benefit of going to stage 2.  They didn't mention any flow measurements in any of the work. Do you know if they even offer flow bench testing?
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Offline 71chally416

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Re: What porting stage to get?
« Reply #5 on: March 10, 2010 - 11:58:33 PM »
Most of the benefit of porting is under the valves and the short turn radius (the floor of the port as it bends into the valve seat)
Hitting the inside of the ports with sandpaper rolls to make it look pretty does nothing for performance. Removing substantial metal around the guide boss and in the ports and substantially increasing the port VOLUME does. I recommend Ryan at Shadydell.

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Offline Chryco Psycho

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Re: What porting stage to get?
« Reply #6 on: March 11, 2010 - 12:54:41 AM »
 :iagree:
 big gains are made in shaping & enlarging around the valve guide & opening & blending  behind the valve .
 Maybe that new RHS [?] head is worth looking at

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Offline moper

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Re: What porting stage to get?
« Reply #7 on: March 11, 2010 - 12:21:07 PM »
The RHS heads can be gotten done properly for $1300 plus shipping. IMO, that's a deal and a 1/2. Personally, if your goal is that cam, I would not do any more than stage one. Simply, your making the port able to flow much more, but the cam has to open the valves and keep them open for that port to work. Mismatch is just tossing money out the window. If that was my build, I'd gasket match the intakes and do the valve job. The 5 angle valve job does the throat and chamber work with the valve job. anything beyond that is wasted. And I wouldnt pay $750 for porting plus a valve job on iron heads unless originality or rules were an issue. And I wouldnt pay any shop who will not mandate a valve job when any porting is done.

Offline 73EStroker

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Re: What porting stage to get?
« Reply #8 on: March 11, 2010 - 02:21:23 PM »
Don't know a lot - but wouldn't you get some reasonably good magnum heads at the wreckers and do the conversion. CP will advise that they flow way better and have the quench chamber. Have to use their rockers and valvegear and the magnum manifold. Or go with the 308 heads with a small porting job?

Another  :2cents: worth but may save some money.
Barry (Salmon Arm)