port/gasket match

[zeeman]

I am doing some work on my lt1. New lifters, new headers. ( Also a new opti and water pump but that doesnt belong in this area) since I have had to take the intake manifold off I decided to go ahead and replace the head gaskets rather than wait for one to fail.
So I figured I could do a port/gasket match on the heads and intake while I was in there any ways. But then I ran across a couple of threads that claim that a port match is a waste of time. So Is it a waste of time? Even if I only gain a little power or just better efficiency I would think it would be worth it. my heads have some good size areas that protrude into the air flow in each runner.


Any thoughts?

[MONGO]

I wouldnt really say it is a waste of time. Every little bit helps but you probably wont notice any real difference with just a port match. If your already in there, It wouldnt hurt to do it just dont expect alot.

[TB2]

Gasket match will give small increases. But it all adds up. Most of the improvements come from the area under the seats.

[zeeman]

Gasket match will give small increases. But it all adds up. Most of the improvements come from the area under the seats.

Could you be a bit more specific? Theres a lot of stuff under there. are we talking about the rest of the exhaust system, cats and what not or something else?

[Lucky SOB]

He's referencing the valve seats

I think he's suggesting having some port and polish work done to the runners. If it were me, I would port match them, it can't hurt. Just be careful not to crack the gasket when handling it so much.

Also, this is a great time to ask what type of gaskets you're using? I know there is a certain Felpro favorite for LT1s. @JoeliusZ28 can help guide you on this. He will also probably suggest getting head gaskets from an Impala LT1 to bump your compression.

[hoogiesngrinderz]

I lay the gasket on the head and sharpie the exposed metal on the intake, then do the same for the head. I have a nice carbide bit for my air tool that makes quick work of it all.

Big difference? No. But it takes me an hour to do and I can check the ports while doing so.

[JoeliusZ28]

My car is putting 373 to the wheels and there is no porting or special gasket work done to the heads or intake. I did have some cleanup work done at the valve bowl like TB2 suggested. I also had my heads milled .020" and used an impala gasket to acheive 11.6:1 static compression. The car runs well with an ai 226:234 cam. I wouldnt say porting is a waste of time, but many people arent maximizing the potential of whats there in the first place. A free flowing exhaust, intake and a good cam can gain you close to 100 horsepower.

[TB2]

Ok, First I would not recommend any porting with the valves in the heads. You can never get all of the grinds out of the ports. Its not worth taking the chance for a couple horsepower. I would highly recommend that if the heads are coming off of the motor, that you disassemble the valves from the heads. Get a valve spring compressor and disassemble. Inspect to determine if a valve job is needed, and replace the valve seals. At this time any porting can be done. Gasket matching included. What I was suggesting is that the biggest obstruction with stock heads is from where they bore the casting to put in the valve seat. The casting is purposely made small to insure they have casting material under the seat for support. This extra material is what your going to want to remove. There's a lot more that can be also be done . http://www.youtube.com/user/HeadPorting/videos

[nascarnate326]

IMO clean up the casting marks and call it good.

Unless you have the correct air drive tools I wouldnt bother with it. I started with a dremel and it was a big cluster. Thankfully my dad bought an air drill made for this exact application.

[Fox Slaughter]

Also you have to watch port matching. Just because a head has a huge hole doesnt mean it will flow better, sometimes worse. It comes down to air velocity. A head that creates a higher velocity can create more power than a larger cc head. When the engine intakes, it sucks air in like a vacuum. If the head has a better velocity then it will suck more in, in the same amount of time which obviously fills the cylinder more. Now if you lose velocity, yes the head can flow more air but in the amount of time you have during in the intake stroke you are really losing oxygen molecules.

[zeeman]

All good points. I am probably going to just do the port match to get rid of the protruding areas of the head, to keep the disruption of the airflow down. I dont plan to do the area on the manifolds for the reason stated above. I am just looking to smooth out the airflow a bit, by removing any thing that would cause disruption of the air flow into the cyl.
I just want to clean things up a bit. I dont want to go into this any further than a port match, as long as the potential is there for some gain. I am looking for small gain through cheap easy changes. Since I am already in there. I am just trying to keep things realistic. If I was to do a port session on the heads, then, well.... I should do a valve job...that'll turn into a 3 or 5 angle valve job, and thats no good without a new lower end.... since I am doing all that I might as well build a 383... well now the trans isnt strong enough and there goes the rear end... So I will just keep things modest and easy.
Ya See, my optispark crapped out, so I was just going to replace it. Well...and the water pump, the weep hole is discolored looks like it may have been....well..weeping But then I figured....what the hell I'm in there I should just replacing the lifters,too, because they rattle when its cold, and one sounds like its coming out of the block...until its warm then its fine. But what the hell I'm in there... There really isnt any sense in doing all this work without changing the head gaskets because if I blow a head gasket next year I'll have to do all this work over......
Now look where I am..

Oh yeah, plus the headers I am getting on monday...... Is there a support group available for people with my affliction?

[Fox Slaughter]

Its called get married so your old lady can force you not to spend money on cars.

[riderman329]

Unless she likes cars just as much as you do then it encouraged!

[nascarnate326]

Or just send them to AI and have them done right by a 5 axis machine.

[zeeman]

Its called get married so your old lady can force you not to spend money on cars.

Nah, done that twice, Im good thanks.