hey guys i changed my intake manifold gasket yesterday and while i had it off, i realized how much meat i could take off the heads and intake and still use the same gaskets. Anyone have an opinion on port matching. What kind of horsepower increase can I expect. What kind of tools should I use? Whats port Polishing and how much time do you think would be needed?

 

I was told by a machinist that you can can 75% of your head's power potential by doing an at home port job and cleaning up the bowls. To gain the other 25% of the head's power potential you should take the heads to a qualified machinist with a flow bench and have them done that way. However a port job with a flow bench is quite expensive.

Just gasket matching the heads and intake may gain you lots it may gain you none...it all depends on what you have to begin with. Personally if it were me I would at the very least gasket match the intake and heads. That's just me though, I go after every little horsepower I can get. Be forewarned though, porting heads and the intake can be time consuming and tedious.

You can take it a step farther and slightly port the heads. This is done by going into the intake runners and exhaust ports and cleaning up any casting marks. Don't go to wild just clean things up a bit. You can use a dremel tool or a die grinder for this (die grinder will be faster and easier).

Be sure to use proper eye protection and respiratory protection (ask me how I know. When I was porting my heads I didn't have eye protection on and caught a little metal filing in the eye. Not fun. It took about 3 days for it to works its way out and trying to sleep was VERY painful. Also wear a mask of some sort. I didn't do this in the beginning but learned very quickly. I spent about a week spitting up cast iron dust :( . Lesson learned.

 

I believe there is a good article in the FAQ section on port and polishing.

 

NO!
pocket port? YES!
pushrod restriction? maybe.(measure and i'll calculate the maximum power)

 

Figure about 25 hours to port match, clean up the bowls, taper the valve stem bosses and touchup the combustion chambers.
If you have a carb or throttle body injection, leave the runners rough for better atomization. If you have port injection smooth the runners for better velocity.
I think these are worth about +5 to 10% with no other changes.

 

Yes... waste of time, won't gain an ounce of air flow or H.P. Saw an article a few years ago, they where they took small block chevy heads, and did a base flow. Then they matched the gaskets to the ports.....no increase identical flow numbers to the base. Highest increase were pocket porting and 3 angle valve grind. Polishing also is a waste of time, eventually, the combustion chambers will get carbon build up.


expect about 10-15 hp increase by just doing the pocket porting and 3 angle valve grind. Be careful, if you don't know what you are doing, you will decrease air flow by messing up the ports. You will need a Die grinder, long and short mandrels, emery rolls, in rough to fine grit, and a cutting tool. Be very careful using the cutting tool, you can easily mess up a good set of heads. Time wise, plan a day for each head, since this is your first attempt.

 

Quote: "Yes... waste of time, won't gain an ounce of air flow or H.P. Saw an article a few years ago, they where they took small block chevy heads, and did a base flow. Then they matched the gaskets to the ports.....no increase identical flow numbers to the base. Highest increase were pocket porting and 3 angle valve grind"

:iagree: I've read numerous articles, backed up by actual dyno testing, that essentially say the same thing.......port matching provides little if any gain in HP or Torque.

 

Topic Post --( Port Matching Worth It ? )

Absolutely ! :) Shift in core during manifold production runs and sometimes cylinder heads make this a wise thing to check for. Even the Intake Gaskets can be off a bit but it must be done correctly as in to use lay out dye, scribe and dial calipers for accuracy .

Now is it manditory ? No but hey, show some pride and do it anyway. Your motor will love you for it ;) and there will be at least some power found.