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gasket match port matching criteria question

  
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gasket match port matching criteria question

 
shawn1969gto shawn1969gto
User | Posts: 171 | Joined: 04/13
Posted: 08/03/13
07:22 AM

Fitting the intake gasket to the head. I noticed that my intake  ports are way larger than the gasket that edelbrock recommends. . I know the heads were  ported a bit. So my question is do the ports on the gasket want to match the ports on the head?  And I port matched the intake maifold to the smaller gaskets. Should I grind more out of the intake. There is a very big difference.  What is the general criteria ?  

mb68bird mb68bird
Enthusiast | Posts: 468 | Joined: 06/10
Posted: 08/03/13
07:36 AM

Just get the correct gaskets that fit the intake ports on the heads and be done with it. Unless there in an extreme mis match in port location on the intake it would just be a waste of time.  

ROWSLEY ROWSLEY
Guru | Posts: 1016 | Joined: 07/11
Posted: 08/03/13
08:44 AM

take the time and port match the intake to the heads. it is not a waste of time!

is there enough materal in the intake gaskets to match them up or do you need to order the bigger port gaskets? what heads do you have?

to do a port match the right way you will need to take a straight edge and mark each port on the head where you can transcribe to the intake with the proper gaskets in place pulled up tight to the water pump housing. that way your ports line up perfectly when your done porting!

the head ports that are bigger than the intake is better than the intake ports being bigger than the head ports! the incoming air would hit the head and cause turbulents with the bigger intake ports.  
76 455/4spd TRANS AM
69 GRAND PRIX 455/5SPD

My71 My71
Guru | Posts: 1251 | Joined: 02/10
Posted: 08/03/13
11:00 AM

Shawn,
What intake are you trying to fit and what heads are you trying to fit them to?

Rowsley/MB68 is correct IMHO. Having smaller intake ports and bigger head ports is a better combo than the other way around. As long as the intake ports are more or less centered in the head ports. it probably won't a difference until you get over 5K RPM. Only problem I can see is at higher RPM's once the fuel/air misture leaves the smaller intake ports and enter the larger head ports it will tend to slow down, loosing some of the velocity to fill the cylinder. So as long as your don't plan on exceeding "street" type RPM's I'd say no big deal. Just match the gaskets to your head.(assuming that doing that does not leave an air gap) Only other alignment issue is horizontal so that the center dividers on the ports are lined up.  
Jim,

shawn1969gto shawn1969gto
User | Posts: 171 | Joined: 04/13
Posted: 08/04/13
06:38 AM

I have the round port edelbrock heads. The guy I bought them from had the ported  but I understood light porting for street /racing. The gaskets that edelbrock calls out for are much smaller than the head port. I have the old edelbrock torker intake. Thanks for the info. So I guess I'll order some gaskets from kauffman racing. And if I wanted I could port the intake more? (plenty of metal there)  but the intake should be ok ..because the ports are smaller?  Thats what I was thinking also. Any correction or info would be appreciated.  Thanks  

70bird 70bird
Guru | Posts: 1064 | Joined: 02/13
Posted: 08/04/13
12:10 PM

Hello

fel pro has different gaskets too, any parts store or race shop can order.

Yes you can port your intake providing the port on the head does not obstruct flow in any way, if it does it should be corrected.

No it is not necessary on a moderate street build.

Ye you will gain some benefit from it.

WARNING - You should paint upper intake surface on head, install gasket, scribe outline of top of gasket so it can go in same location, install intake on head leaving gasket in place. If gasket is larger than intake then outline around top of intake so you can lay it on the intake in the correct location after removing intake from head. Grind away. ROWSLEY had briefly described the process in his post above.

If head needs blending it needs to be blended at least 1/2" in to port. If you simply put a radius on the edge of head so it matches the intake it is about the same as doing nothing at all.  

ROWSLEY ROWSLEY
Guru | Posts: 1016 | Joined: 07/11
Posted: 08/04/13
02:46 PM

i looked up some fel-pro's #1233 port size 1.888 x 2.208 i need to figure out what will work with my eddy heads also.  
76 455/4spd TRANS AM
69 GRAND PRIX 455/5SPD

shawn1969gto shawn1969gto
User | Posts: 171 | Joined: 04/13
Posted: 08/04/13
04:18 PM

Its weird like eddy specs gaskets for the non ram air application  

70bird 70bird
Guru | Posts: 1064 | Joined: 02/13
Posted: 08/04/13
04:32 PM

What suze are the eddy ports?

Eddy should have their own that fit or they should be a std size.

A gasket maker can make them in paper for around $30.00.

Fel pro makes 2 over sizes I think, at least for a "different" brand anyway, lol.  

shawn1969gto shawn1969gto
User | Posts: 171 | Joined: 04/13
Posted: 08/04/13
05:14 PM

I just realized I was using the stock gaskets.  Not the ram air ones. I think I might be ok with the felpro 1223. But the intake a alot more grinding  to go.  

My71 My71
Guru | Posts: 1251 | Joined: 02/10
Posted: 08/04/13
05:18 PM

Shawn,
The Eddy round port heads (performer RPM) are sized as RA IV on the intake side. These gaskets will fit that.
http://www.summitracing.com/parts/edl-7280/overview/make/pontiac

If your intake has been ported, these may even be to small and restrictive. If they extend into the port area any at all, they will tend to act like a wall that the F/A mixture hits and tends to drop the fuel out of the air causing small droplets to form. You'll loose a fair amount of power that way.  You may end up making a custom set of intake gaskets if the RA IV's are too small. If your intake port is even smaller yet, that may be your saving grace. If you port match the intake to the heads, then pay close attention to the gaskets and if they extend down into the port area or not.  
Jim,

shawn1969gto shawn1969gto
User | Posts: 171 | Joined: 04/13
Posted: 08/04/13
05:36 PM

Thanks. You guys are very helpful. So what I did was gasket match my intake to a stock gasket.. not ram air.  I just ordered the fel-pro 1233 from summit.. Then I will gasket match the intake and will keep in mind to not go so far as to surpass the ports on the head. Sound good? Good thing I didnt just bolt this junk together lol. " Cut it twice and its still to short"...next question. . Rejet the carb to accommodate the new port size? Whats the rule of thumb here. Go up?? 3 jet sizes mabey?  

ROWSLEY ROWSLEY
Guru | Posts: 1016 | Joined: 07/11
Posted: 08/04/13
07:12 PM

run it with new plugs first and read them to see what it needs.

um what carb and jets are you using now?  
76 455/4spd TRANS AM
69 GRAND PRIX 455/5SPD

shawn1969gto shawn1969gto
User | Posts: 171 | Joined: 04/13
Posted: 08/04/13
07:28 PM

I have a number matching quadrajet.  I never opened it. Bought from a guy who had a firebird.  It runs great with rhis carb. Seems a like it could take more fuel now. I would guess the jets are stock for 1969 gto. Should be pretty easy to change.. what do I so pull the too of the carb off. I also have a 795cfm quadrajet edelbrock carb 1904. It is what came on the car  when I bought it. I have a rebuild kit for it. Whats with checking the plugs? How does that work  

70bird 70bird
Guru | Posts: 1064 | Joined: 02/13
Posted: 08/04/13
07:51 PM

Yeah, pull the carb top, check jet size and simply buy 3 sizes larger.

Drive it for a day or so then check plug color.  

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