Port/Polishing stock heads
01-18-2008, 11:38 AM
#1
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Port/Polishing stock heads
I was wondering what the benifits of porting and polishing the stock heads are compared to just buying aftermarket heads. Is there a significant price difference? Would it be worth the money to port and polish the stock heads or go ahead and buy an aftermarket setup? What kind of horse power gains would I see with each setup with cams (BBR stage 2's)? I looked up on BBR's website and they claim with a good tune that their heads and cams can get our cars at 375 rwhp.
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01-18-2008, 11:48 AM
#2
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RE: Port/Polishing stock heads
Im pretty sure that most companys who sell P&P heads are using stock castings and P&P those out. I personally think that if you have the money laying around for it go ahead and do it. If you stay n/a you will get some hp and if you go with a power adder you will still benefit hp. As far as hp wise with ported heads and cam im not sure. BBR claim they made 400rwhp with their n/a car but who knows. I am planning on doing it when I have the money for it.
01-18-2008, 12:08 PM
#3
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RE: Port/Polishing stock heads
Porting heads refers to inlarging (usually to match the gaskets)the intake and exhaust "ports" in a cylinder head to improve flow.Polishing heads refers to cleaning up of or"polishing" the combustion chamber or valve pocket of the heads to again improve flow & adamisation of the air fuel mixture.
Most aftermarket heads,such as AFR or Edlebrock design these features in there heads and usually increase the valve sizes too,but at a greater cost.Horse power gains are dependant on many factors,Valve size & design,combustion chamber size & design,Port length,size & design,ect.
When chooseing the heads you want you have to concider what the primary use of the vehicle will be street/strip,full drag ect. The choise is yours.Hope this Helps
Most aftermarket heads,such as AFR or Edlebrock design these features in there heads and usually increase the valve sizes too,but at a greater cost.Horse power gains are dependant on many factors,Valve size & design,combustion chamber size & design,Port length,size & design,ect.
When chooseing the heads you want you have to concider what the primary use of the vehicle will be street/strip,full drag ect. The choise is yours.Hope this Helps
01-18-2008, 01:37 PM
#4
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RE: Port/Polishing stock heads
Ditto. Usually the companies offering complete p/p heads want your core back for some savings cause they do the p/p job on stock heads.
The reality is a p/p alone isn't really that big of a deal on the S197 IMO. Don't get me wrong, it's a good thing to do but more important IMO is upgrading the valve train. More important than the P/P job to me, is the upgraded 1mm oversize inconel exhaust & intake valves, titanium springs & retainers, and brass guides. If you start making some decent power, these are the places of the valve train you want to reinforce IMO.
Just to give you an idea of how important, the majority of big horse power motors that let go are usually related first to a failure in the valve train...
The reality is a p/p alone isn't really that big of a deal on the S197 IMO. Don't get me wrong, it's a good thing to do but more important IMO is upgrading the valve train. More important than the P/P job to me, is the upgraded 1mm oversize inconel exhaust & intake valves, titanium springs & retainers, and brass guides. If you start making some decent power, these are the places of the valve train you want to reinforce IMO.
Just to give you an idea of how important, the majority of big horse power motors that let go are usually related first to a failure in the valve train...
01-18-2008, 02:06 PM
#5
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RE: Port/Polishing stock heads
ORIGINAL: modaddict
Ditto. Usually the companies offering complete p/p heads want your core back for some savings cause they do the p/p job on stock heads.
The reality is a p/p alone isn't really that big of a deal on the S197 IMO. Don't get me wrong, it's a good thing to do but more important IMO is upgrading the valve train. More important than the P/P job to me, is the upgraded 1mm oversize inconel exhaust & intake valves, titanium springs & retainers, and brass guides. If you start making some decent power, these are the places of the valve train you want to reinforce IMO.
Just to give you an idea of how important, the majority of big horse power motors that let go are usually related first to a failure in the valve train...
Ditto. Usually the companies offering complete p/p heads want your core back for some savings cause they do the p/p job on stock heads.
The reality is a p/p alone isn't really that big of a deal on the S197 IMO. Don't get me wrong, it's a good thing to do but more important IMO is upgrading the valve train. More important than the P/P job to me, is the upgraded 1mm oversize inconel exhaust & intake valves, titanium springs & retainers, and brass guides. If you start making some decent power, these are the places of the valve train you want to reinforce IMO.
Just to give you an idea of how important, the majority of big horse power motors that let go are usually related first to a failure in the valve train...
From my understanding seems the 3V heads (flowgood also due to theredesign) have already big ports to begin with and really don't need much work. You always hear about P&P to open up the heads for flow truth is the 3V heads need very little material removed and in some areas material added.
Yep bigger valves, 3 angle V job, hardware mentioned by Markand some work in bowls plusand you pick around 40rwhp 20rwtq with the 3V heads.
01-18-2008, 02:14 PM
#7
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RE: Port/Polishing stock heads
Correct. This is the exact reason I'm putting together the 342ci motor on the 3V platform. Several guys have done the big bore 4.6 motors but all of them have done it on the 4V. I really think the 3V platform is going to unleash a beast with these new cubes and I can't wait to fire it up in a couple weeks...
I've been involved in a half dozen P/P jobs on these heads and I can tell you that it is never 'shocking' or 'surprising' how much material ends up coming out. It's nowhere near the obvious visual of a pushrod. It's always more of a 'cleaning up' job IMO and not that big of a deal if you saw them side by side a stocker.
Nope, beefing up the valve train is where your money is best spent and the P/P job is just kind of a bonus.
I've been involved in a half dozen P/P jobs on these heads and I can tell you that it is never 'shocking' or 'surprising' how much material ends up coming out. It's nowhere near the obvious visual of a pushrod. It's always more of a 'cleaning up' job IMO and not that big of a deal if you saw them side by side a stocker.
Nope, beefing up the valve train is where your money is best spent and the P/P job is just kind of a bonus.
01-18-2008, 05:49 PM
#8
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RE: Port/Polishing stock heads
The machine shop I talked to said the intake doesnt need much more than some cleanup. The exhaust side on the other hand needs alot of work Im sure partially because of the 2 valves feeding one. Everyone Ive talked to estimate between $1400 to $1600.
01-20-2008, 06:51 PM
#9
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RE: Port/Polishing stock heads
ORIGINAL: modaddict
Correct. This is the exact reason I'm putting together the 342ci motor on the 3V platform. Several guys have done the big bore 4.6 motors but all of them have done it on the 4V. I really think the 3V platform is going to unleash a beast with these new cubes and I can't wait to fire it up in a couple weeks...
I've been involved in a half dozen P/P jobs on these heads and I can tell you that it is never 'shocking' or 'surprising' how much material ends up coming out. It's nowhere near the obvious visual of a pushrod. It's always more of a 'cleaning up' job IMO and not that big of a deal if you saw them side by side a stocker.
Nope, beefing up the valve train is where your money is best spent and the P/P job is just kind of a bonus.
Correct. This is the exact reason I'm putting together the 342ci motor on the 3V platform. Several guys have done the big bore 4.6 motors but all of them have done it on the 4V. I really think the 3V platform is going to unleash a beast with these new cubes and I can't wait to fire it up in a couple weeks...
I've been involved in a half dozen P/P jobs on these heads and I can tell you that it is never 'shocking' or 'surprising' how much material ends up coming out. It's nowhere near the obvious visual of a pushrod. It's always more of a 'cleaning up' job IMO and not that big of a deal if you saw them side by side a stocker.
Nope, beefing up the valve train is where your money is best spent and the P/P job is just kind of a bonus.
01-20-2008, 08:51 PM
#10
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RE: Port/Polishing stock heads
ORIGINAL: iwannagofast
The machine shop I talked to said the intake doesnt need much more than some cleanup. The exhaust side on the other hand needs alot of work Im sure partially because of the 2 valves feeding one. Everyone Ive talked to estimate between $1400 to $1600.
The machine shop I talked to said the intake doesnt need much more than some cleanup. The exhaust side on the other hand needs alot of work Im sure partially because of the 2 valves feeding one. Everyone Ive talked to estimate between $1400 to $1600.