hey guys I plan to port out a set of 3.1 heads for my car soon, then have a 3 angle valve job done. Heres the plan.....

1 gasket match to the intake manifold, while keeping the ports small as possible to keep the velocity high.

2 smooth the valve guide boss over(this is the thing that the valve sticks out of, it seems very sharp and could use some smoothing, a book I read recomended smothing it over)

3 smooth the sharp edge on the short side radius( this part kinda scares me)

4 smooth rough edges in the combustion chamber

5 polish the exhaust ports, but not enlarging them

6 have a 3 angle valve job done

7 gasket match th intake manifold and the lower and upper plenum

Does this seem like a good plan? I;ve never done this before, o I dont wanna do anything that would mess the heads up.

 

This sounds like a plan, i took mine down and had them done over for about 350.00 They ported and polished, new valves, springs locks ect ect. There sitting on the table along with a redone intake, TB gaskets all that other stuff. I think you will see better breathing and some torque/HP gains in this especially since you have other mods. Goes without saying to match the springs to your cam, i have the CompuCam's cam for the engine. Oh one last thing, i have heard shaving the heads will up the compression alil, i did that as well, unsure what the final comp will be but if its the 8.9 i beleive it will bump into the low 9's. Anyways i hope it goes well for you, lets us know how it feels before/after, get some times on that thing too BTW, i want pics of the headers lol....




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David
91 Firebird

3.1L MPFI
Dynomax exhaust, cold air, 8mm wires, splitfires, shift kit, B&M Shifter.

On the table waiting to go in:

Ported/polished iron heads, 1.6:1 rockers, Lightly ported/Gasket matched Intake. Ported/Polished TB, Compucam 2030, 5" tach, duel pod w/oil temp, tranny temp gauges. Hood pod w/Fuel pressure, NOS pressure.

Coming Soon:
FastChip, 275 rears, 235 fronts, Ram air hood, suspension mods.

 

I'm a bit curious to one spot on the intake manifold, where the injectors stick in. Looks like "half" the injector spray hits the incoming air, but the other half hits the wall of the intake manifold. I wonder if enlarging that spot around the injector tip would help matters...


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-Tom P (Hot rodded 1986 Firebird 2.8l) from http://www.f-body.net/mailbag/3rd/3rd_mailbag.html message boards

 

1 gasket match to the intake manifold, while keeping the ports small as possible to keep the velocity high.

fine, minimal gains though

2 smooth the valve guide boss over(this is the thing that the valve sticks out of, it seems very sharp and could use some smoothing, a book I read recomended smothing it over)

You want to thin it down so that there is more room for the air to move around the valve guide. The exhaust is the worst for this, major reshaping required.

3 smooth the sharp edge on the short side radius( this part kinda scares me)

don't touch this area without a flow bench!

4 smooth rough edges in the combustion chamber

fine.

5 polish the exhaust ports, but not enlarging them

fine.

6 have a 3 angle valve job done

fine, although I think GM did a 4 angle on the Fiero heads...

7 gasket match th intake manifold and the lower and upper plenum

again, minimal gains


YMMV and the usual disclaimers apply, etc...

 

thanks for al the advice. Dobber, thats why I was worried about messing with the short side radius because I personally dont see how you would know whether or not your inproving flow or hurting it by messin in that area.