Manifold porting

[L31MaxExpress]

About 1/2 way into the port from the head flange side, the manifold has a substantial dip in CSA and if you are making good power and want to rev it a bit, the CSA needs to increase there. I discovered the manifold has alot of material there incedentaly, figured I would break through on atleast one runner but never did.

 

[Hipster]

What I don't do is bell mouth the ports opening to a big gasket size. If you're not going deep into the runner on the head or intake checking cross sectional areas it's counter-productive to make the openings bigger. Another thing I always address on a build is the chambers. There's some to be had by dressing the chambers and removing the machining ridges that typically surround the valves, .020-.030 cut on the heads to tighten the chambers, and a good 3 angle VJ with a 75-80 degree bowl cut that can easily be hand blended. If you're going to go for it, go for it all. LOL

 

[Vikingdude]

Got into the cartridge rolls today. 80, 100, 120, and 240. A few spots still need touching up, but I'm close to being complete. I'm not tweaking the port shape or volume much. Without a flowbench, I have no way of telling if I'm moving in the right direction, and this is my first time porting so I'll leave it fairly mild. Just removing the big boogers and ridges in the stick castings.

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[Erik the Awful]

I wouldn't bother with the 240 grit. You don't want a smooth finish or fuel can fall out of suspension and puddle.

 

[Pro439]

On my intake I filled the valley and took down the big bumps at the edge of all the runners to make as smooth of a transition as possible. Used a long rod and scroll to straighten up the port so it didn’t have all the casting left in it but I did not really open the actual runner and I used Edelbrock 170 vortec intake gaskets which are paper and are very close to the stock port. I only needed to take just a tad out and not all the way around either. I was waiting on a crank trigger and FAST had no eta so I cut out a wheel from cardboard and had a fab shop with a water jet cut it out and now I just have to get time to finish the sensor bracket as I am using the stock crank sensor

 

[Pinger]

I wouldn't bother with the 240 grit. You don't want a smooth finish or fuel can fall out of suspension and puddle.

Only downstream of the injectors...

 

[Vikingdude]

I wouldn't bother with the 240 grit. You don't want a smooth finish or fuel can fall out of suspension and puddle.

Not above the injectors it won't!

 

[alpinecrick]

This is so tempting to try......

 

[L31MaxExpress]

Only downstream of the injectors...

Not exactly. Reversion will push the fuel back as will the fact the injectors spray on the back of the closed valve.

 

[Vikingdude]

Without access to a dyno or flowbench, this could all be an exercise in futility at best, a reduction in performance at worst. If nothing else, I spent some time outside, working on my truck, and I drank a beer.