Projects Porting Exhaust Manifolds

I have a set of Ford V8 flattie exhaust manifolds. Was wondering if they could be ported some or at least blended internally? Seems I've heard old school guys etching it internally with acid for better flow.

 

https://www.extrudehoneafm.com/faqs/faq-automotive/

Extrude Honing - Always though this process was cool, abrasive "goo" run thru the p***ages to internally port or blend castings.

By hand, you need a good selection of bits, it goes a lot slower than you think. Electric die grinder is preferred.

 

Ports in the block flow so poorly I’m not sure you will see any benefit from it. Maybe match the ports and clean them up a bit but I wouldn’t spend much time on them.

 

And to complicate matters, you can only port so far into the block. Now add the shared center port and more things to complicate flow.
But for sure any cleanup and smoother bends has to be beneficial for more power potential. Just within controlled sense because there will always be a limiting factor. That limiting will move as you change or modify parts.

 

On one hand, I would...go in and remove casting marks, interruptions to flow, steps, etc. But that's just me...

BUT, like others have said, is it "really" gonna matter that much ?
Especially...if you drive only on the street, and aren't doing any racing. I seriously doubt you'll see any horse power or drivability increase.

But, yeah...I would clean out all of the boggers and all... That only comes from my cylinder head porting side of my brain..!

Mike

 

To save you some time; the experienced hands on the "Barn" tell us that installing headers won't change anything unless ya use a hotter cam.
A hot cam for that matter only helps top end.
For best pull off the line, focus on raising compression by milling the heads. Using balls of tin foil is a good way to measure the clearance between head and pistons and valves.
Getting the clearance close without the gasket, then the gasket ( composition ) when torqued should give you .040 clearance

 

I always thought the cast iron manifolds were the first thing to go in the s**** pile after you added a dual intake. I surely wouldn't waste any time porting them.

 

Standard factory exhaust manifolds have only one design focus, collect exhaust g***es at the ports, route them through the ch***is and suspension to a place where an extension pipe can be connected, and do it cheaply. Ford was the master at simple cheap log manifolds. The g***es blast out of the port, hit a wall, turn 90 degrees with virtually zero radius and compete for space with two other ports along the way. I suppose you could fill dead spaces and grind in some radii somehow in some places but I’m pretty sure that all your work won’t be felt by your **** dyno.
As Mike VV said, grind out any nasty casting flash or lumps, deburr and run ‘em. In my opinion, in most cases, a hot rod needs a cool set of tubing headers but we don’t know if your building a hot rod or something more stock/restored.