Port Polish? How Much H.P.? - The 1947 - Present Chevrolet & GMC Truck Message Board Network

orange72350 · 10-03-2003, 12:29 AM

Got a set of stock heads on a 350. whats it gonna cost me to get them polished? if its cheap enough, im gonna go ahead and do it. how much power is this kinda thing gonna get me?
thanx
dale

orange72350 · 10-03-2003, 01:00 PM

ttt

bigjimzlll · 10-03-2003, 01:14 PM

A decent bowl port with polished chambers and exhaust ports will net around 10% more flow...so if your stock heads flow 170cfm @ .500" of intake valve lift it will now flow 187 cfm. Using AFR's formula...257x flowx cylinders = max available HP means stock the max Hp is 349.5 and with the port work the HP is 380. You can expect to pay 300.00 for a middle of the road port and polish. After you pay that you will have a set of heads that dont compare to aftermarkets or vortecs. Also port work will decrease the lowend power somewhat. One more thing...sometime(if the wrong person does the work) the port work will HURT performance. My suggestion is to take the 300.00 and save another 400.00 and by a set of protopine or equivilant. This will net you over 50HP...even alot more if you upgrade the cam

mdill · 10-03-2003, 03:57 PM

It depends on if the ports are your limiting
factor. For low RPM mild cam engine messing with
the ports won't produce much if any differance.
If the rest of your induction system and exhast
system and your cam is such that head flow is
a limiting factor them porting can produce
significant differances. For most trucks it is
a waste of $ ,time effort, for the light weight
street guys with big cams, intakes, headers then
it might make some sence.
Mike D.

10-03-2003, 12:29 AM	#1
orange72350 Registered User Join Date: Jan 2003 Location: Cold, Snowy High Level, Alberta Canada Eh Posts: 394	Port Polish? How Much H.P.? Got a set of stock heads on a 350. whats it gonna cost me to get them polished? if its cheap enough, im gonna go ahead and do it. how much power is this kinda thing gonna get me? thanx dale __________________ 2003 yamaha raptor. Stock, but it still hauls!!!! 2000 skiddo mxz 700. Camoplast 1.5 inch track, jaws twin pipes, b+b can, custom built and weighted clutch, wiseco piston, high comp heads. its very fast. wow. 72 c-10 longbox. Bright Orange. Brand new 350, rv cam, performer intake, qjet, headers, 2 1/2 inch exhaust into hooker areo chamber mufflers. Body work coming soon. "dont let yer mind wander, its to little to go places by itself." "Forget the herse, cause i'll never die"-ACDC Back In Black "If It's To Loud, Yer Just Too Old" "I Love Anything Fast Enough To Do Something Stupid In" "Instant idiot, just add beer!!""

10-03-2003, 01:00 PM	#2
orange72350 Registered User Join Date: Jan 2003 Location: Cold, Snowy High Level, Alberta Canada Eh Posts: 394	ttt __________________ 2003 yamaha raptor. Stock, but it still hauls!!!! 2000 skiddo mxz 700. Camoplast 1.5 inch track, jaws twin pipes, b+b can, custom built and weighted clutch, wiseco piston, high comp heads. its very fast. wow. 72 c-10 longbox. Bright Orange. Brand new 350, rv cam, performer intake, qjet, headers, 2 1/2 inch exhaust into hooker areo chamber mufflers. Body work coming soon. "dont let yer mind wander, its to little to go places by itself." "Forget the herse, cause i'll never die"-ACDC Back In Black "If It's To Loud, Yer Just Too Old" "I Love Anything Fast Enough To Do Something Stupid In" "Instant idiot, just add beer!!""

10-03-2003, 01:14 PM	#3
bigjimzlll Senior Member Join Date: Dec 2001 Location: Redding,CA...USA Posts: 4,736	A decent bowl port with polished chambers and exhaust ports will net around 10% more flow...so if your stock heads flow 170cfm @ .500" of intake valve lift it will now flow 187 cfm. Using AFR's formula...257x flowx cylinders = max available HP means stock the max Hp is 349.5 and with the port work the HP is 380. You can expect to pay 300.00 for a middle of the road port and polish. After you pay that you will have a set of heads that dont compare to aftermarkets or vortecs. Also port work will decrease the lowend power somewhat. One more thing...sometime(if the wrong person does the work) the port work will HURT performance. My suggestion is to take the 300.00 and save another 400.00 and by a set of protopine or equivilant. This will net you over 50HP...even alot more if you upgrade the cam __________________ It's called "drag racing" if they called it "tic..tic..WHAM!..BANG! F*&K!!!", they'd have to keep the magazines under the counter with the other men's publications click the clicky to join the site.... http://67-72chevytrucks.com/vboard/payments.php 67 lwb..first hotrod in 25 years..540 best ET is 9.45 @ 141.44 Anderson,CA

10-03-2003, 03:57 PM	#4
mdill Registered User Join Date: Jun 2003 Location: Richfield MN Posts: 44	It depends on if the ports are your limiting factor. For low RPM mild cam engine messing with the ports won't produce much if any differance. If the rest of your induction system and exhast system and your cam is such that head flow is a limiting factor them porting can produce significant differances. For most trucks it is a waste of $ ,time effort, for the light weight street guys with big cams, intakes, headers then it might make some sence. Mike D. __________________ 72 3/4 ton 4X4 Suburban (and way to many FSJ's (J series jeeps)



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