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View Full Version : A few head questions.



Pacman
10-22-2009, 07:52 AM
1: Does anyone have pictures of ported heads so i can get an idea where to start?

2: How much can be safely milled off of SC heads before affecting CR?

LukewarmSteak
10-23-2009, 08:09 PM
i recently ported my heads with a die grinder ( you better be good with one... )

the middle intake port can be opened way way up... but only if you tig weld the two spots where you will break through... and be very sure not to nick or scratch the valve seats

when i machined the head surface i only took a max of 0.003" all around
i used a milling machine with a 6.5" single point fly cutter (hss tip was all that was needed) and good set up

rapper33142
10-23-2009, 08:44 PM
I have never ported so I hope I don't XXXXXXXX

fturner
10-23-2009, 09:59 PM
Be very careful with the short radious especially on the exhaust port. You go just a tad too much and it'll flow worse than stock.

Fraser

thirdbird
10-23-2009, 10:29 PM
Be very careful with the short radious especially on the exhaust port.
Fraser

Please explain ?
thx!

Pacman
10-24-2009, 05:13 AM
Pictures anyone?? these heads are gasket matched already but since they are off i thought what the heck. I was thinking the same thing about a fly cutter to mill them but havent quite figured out how to set it up. I thought about clamping them directly to the table and indicating the head of the mill to the cyl head surface.

thirdbird
10-24-2009, 11:05 AM
I never had to have a head milled yet, just lucky I guess..
I ported the exhaust side only on mine.
Didn't really enlarge it much or change the shape,
just opened the outlets to match the inlets of the exh. mani,
leveled the guides, and smoothed everything.
The intake ports don't seem to need help for the mods I have done.
The restrictions don't show much til over 300whp (If I am reading things correctly).
I don't expect more than 250.
http://i258.photobucket.com/albums/hh251/paulpatrick3/minivan/1015091417-00.jpg
http://i258.photobucket.com/albums/hh251/paulpatrick3/minivan/1015091419-02.jpg
paul

Pacman
10-25-2009, 04:37 PM
I always heard to not touch the exhaust side? is it ok to levl the guides on the intake side?

nickleman60
10-25-2009, 05:59 PM
Here's a good cut away picture of stock heads compared to ported heads, stock are top photos and ported are bottom photos, you can definately see what's been done to intake and exhaust ports.

http://rides.webshots.com/photo/1248413468034851261rjptgI

Pacman
10-27-2009, 04:20 PM
Cool the cutaway pictures are very helpful! how much can one gain from a good port job? im running the stage II cam that SCP sells if that helps.

XxSlowpokexX
10-27-2009, 07:12 PM
Are those good representative photos? Also anyone have photos of bowl work..May help him out

Roadhawg
10-27-2009, 07:41 PM
I ported the exhaust side only on mine.
Didn't really enlarge it much or change the shape,
just opened the outlets to match the inlets of the exh. mani,
leveled the guides, and smoothed everything.

http://i258.photobucket.com/albums/hh251/paulpatrick3/minivan/1015091419-02.jpg

paul

I would avoid port matching or even enlarging the exhaust port gasket area. Also, I would not cut down the valve guides, they provide valve stem stability.

Stupid Canuck
10-27-2009, 07:53 PM
Cool the cutaway pictures are very helpful! how much can one gain from a good port job? im running the stage II cam that SCP sells if that helps.

Have yet to see anyone make 300 rwhp without significant head porting. With that cam, good heads, MP intake, and 42's or more, exhaust ... 300 should be easy with just 10% OD. Maybe 30 horses, depending.

Regul8r
10-27-2009, 08:05 PM
Great pics of the port.

Someone tell me who's this is!?
http://rides.webshots.com/photo/1104834605034851261eMIeOW

Dual Blowers? Inverted?

thunderkid84
10-27-2009, 08:15 PM
mannysc

he's not on here anymore but used to do alot of port work for members here.

he ended up with some bad luck and family problems and had to go take care of that stuff

Pacman
10-28-2009, 04:24 PM
Have yet to see anyone make 300 rwhp without significant head porting. With that cam, good heads, MP intake, and 42's or more, exhaust ... 300 should be easy with just 10% OD. Maybe 30 horses, depending.

I've also got a 76mm MAF full exhaust catless downtubes magnaflow resonator and mufflers. Ported late model blower with 10% js pulley IC fan. So with a good head port job and 42's i could see 300?

thunderkid84
10-28-2009, 05:59 PM
with everything i have in my member page i estimate im making 260-270 rwhp.

of course i havent been on a dyno, thats why its an estimate based on my 1/4 mile time. i need to get on a dyno and verify my AFR.

but anyways, i'd put a cam in (even a mild one) if i was gonna pull heads off to port them

just a thought

Pacman
10-28-2009, 06:02 PM
I already have the stage II cam that scp sells.

neverfastenough
10-28-2009, 06:06 PM
with everything i have in my member page i estimate im making 260-270 rwhp.

of course i havent been on a dyno, thats why its an estimate based on my 1/4 mile time. i need to get on a dyno and verify my AFR.

but anyways, i'd put a cam in (even a mild one) if i was gonna pull heads off to port them

just a thought


Just a thought, I make 274 and trap 104. If your are making 260-270 I think you'd be trapping 100+. But Id dyno it anyway and see where you're at.

Corey

thunderkid84
10-28-2009, 06:08 PM
Just a thought, I make 274 and trap 104. If your are making 260-270 I think you'd be trapping 100+. But Id dyno it anyway and see where you're at.

Corey

like i said, just an estimate. dont wanna get anyone started...

what have u done with yours ?

neverfastenough
10-28-2009, 06:13 PM
like i said, just an estimate. dont wanna get anyone started...

what have u done with yours ?

Yea I didnt want to start anything, just trying to help with you're estimate. HP numbers mean nothing IMO dynos are for tuning and AFR if you ask me. Mine is a stock long block bolt on queen, running a pretty high ammount of boost for a ported late model. Its a 5spd with 273 gears. I can say however, going by your sig, your car can go much quicker with 97mph. 14.0 would be a good number.

Corey

thunderkid84
10-28-2009, 06:18 PM
i think i might have messed something up when i ported the heads myself. and thats y its not performing like it should. but who knows :confused:

but im just gonna put that in the past and get a cam and heads from Dalke

Stupid Canuck
10-28-2009, 10:42 PM
I pulled 287 rwhp (282 with 5%), @ 4900 rpm, with an auto, Morana 3+ heads, Comp stage 2 and a mildly ported late model with stock inlet plenum and TB (upgraded since). 42's probably maxed out. Some dynos are friendlier than others but that was on a 90 degree day too.

Idle is not ideal but I got tuning to do so I'm not gonna blame the cam yet.

Pacman
10-31-2009, 07:34 PM
So opening it up to the gasket size on the intake ports andonly working on the short radius is ok? also on exhaust sideis it ok to enlargethe ports to the manifold size or not?

thunderkid84
10-31-2009, 10:02 PM
So opening it up to the gasket size on the intake ports andonly working on the short radius is ok? also on exhaust sideis it ok to enlargethe ports to the manifold size or not?

IMO i'd let someone who knows how to work with sc heads instead trying to do something yourself

but thats just me

thirdbird
11-01-2009, 12:01 PM
So opening it up to the gasket size on the intake ports andonly working on the short radius is ok? also on exhaust sideis it ok to enlargethe ports to the manifold size or not?

You are only going to get opinions on that one.
I matched the intake ports to the head ports, (taller) and radius-ed the casting between plenum and each port.
I made the exhaust bowls and ports smooth and steady, and added a bit more radius in the head toward the end of the ports to favor/complement the exhaust manifold inlet radius.
Exh. Manis are ported too, laid down the pinch to more of a ramp at the inlet, and the collectors are a little over 2" now...


paul

thirdbird
07-31-2010, 01:24 AM
I would avoid port matching or even enlarging the exhaust port gasket area. Also, I would not cut down the valve guides, they provide valve stem stability.

I think I removed about 4mm on the outlet side, so bunk upon the above statement.