View Full Version : guess my hp gain from home head port work

03-08-2003, 01:20 AM
i know i know you need a flow chart and all this other stuff to know put a good number to gather i just wanted to know if i will pick up 10hp 15hp 20hp 25hp from this

i have a pic i marked the 3 spots i work on in the exhaust port.

1 the bump on the side is gone
2 the valve guide is nice and smooth
3 the lip on the bottem by the valve is nice and smooth

i have not done anthing to the intake yet if you have any thing to helpful on the intake please add it

i will try and open up the exhaust manifold to 2" also

ps this is not my head i just used this pic

David Neibert
03-08-2003, 11:01 AM

It all depends on what other mods you have and where your bottlekneck is now. I would expect more gains from porting the exhaust manifolds than from what you have done to the exhaust ports on the heads.

I'm guessing 10-15 HP if you port the manifolds too, 5 if you don't.


03-08-2003, 12:03 PM
Is it a good idea to grind the valve guides flush like that? I was under the impression that you shouldn't touch those. I'd be afraid of bending or breaking a valve due to less lateral support from the valve guide. Just wondering.

03-08-2003, 12:33 PM
If your exhaust ports look anywhere close to those I would say you have an EASY 15rwhp gain. Add a decentcam and your looking at another 20-30rwhp.

03-09-2003, 08:48 PM
is the main thing to open the exhaust manifolds up to 2 inches on the cat end
will i gain from doing any work on the other end feeling the walls it did not feel very thick i may polish but not port

and i gasket match the intake on hte head and i will to the intake


03-09-2003, 11:12 PM
You shouuld get 25hp easy.

Here's what I had for mods:

ported stock valve heads (full exhaust, bowl work only on intake)
94 blower w/'91 pulley
custom 2 1/4"-3"-2 1/4" cat back, stock unported manifolds
190 lph fuel pump
1" raised top
stock everything else

Result? 260 RWHP and 350 RWT. That's about 60-70 hp and 40-50 T over a typical stock SC. And the rest of the motor had 140K miles at the time.

Opening up the heads was prolly 50% of my gain with the blower and exhaust being 20% each.

Good luck,

93 Mark VIII
03-09-2003, 11:24 PM
haha nice pic :)

just be careful with those valve guides, if you trim them you need to debur and clean em good.