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I'm looking for second opinion on whether to do a DIY porting of my 351w heads. The engine is on a stand as I am in the process of rebuilding with some help. Inside the exhaust ports there is a hump that ford calls thermactor injection hump. Can I remove this hump?
That hump is most likely a hollow passageway and you might run the risk of breaking through. I had ported heads once on a 302 with 289 heads and it really killed the low end torque but at high rpms on the highway it was very powerful. I had valve float once and had to replace a valve but got lucky it did not trash the head. I gasket matched the ports to the intake and cleaned everything up and evened out the passages. It was almost twenty years ago and I did all the work with an electric drill! I spent like eight hours doing it and my hands vibrated for a day after. All said and done I would not do it again due to the lose of power off the line and bottom end. Hope this helps.
Unless you are looking for absolute MAX power mat I suggest gasket match and tidy the inlet tracts - For the exhaust a set proven headers with a gasket match to the head BUT opent up the exhaust flange about 3/32" all round.
It then becomes 'anti reversion' and will assist gas flow. My $0.02.
The hump in my 69 351W heads were solid. I assume, but am not certain, they are all like that. The thermactor passages are drilled after casting and not cast into the cylinder heads. Porting work is best done with the cylinders heads disassembled before any valve grinding work is performed so be careful if you do it.

Honestly, from my experience I don't know how you can do a sufficient job with a drill. After the machine shop instructed me what to do I spend about 2 weeks, after work and weekends, with pneumatic die grinders, several carbide burrs, and a ton of sanding drums. 90% of that time was in the exhaust ports. You can purchase porting kits from Summit Racing or Jegs that have various sanding drums and some general instructions. You also need about 6 or 8 carbide burrs because the sanding drums are for finish work and cannot remove enough material.

A 351W makes a lot of torque compared to 302's and 289's so I wouldn't worry about loosing low end torque. In stock form, the exhaust ports are pretty bad. Headers and a camshaft shaft upgrade would help take advantage of any port work.

Its hard to say yes or no to your question. You will have to ultimately decide. I did mine. I would do it again if I couldn't afford an aftermarket cylinder head.

Good Luck.

Best Regards,
Mike
OK, thanks for the comments. The valves are still in and I would hate to remove them. Can I port the exhaust with valves in?
Turn the engine to shut each valve in turn. Stuff the port with rag while the work is in progress. Remove the rag and blow out with compressed air. That should be enough.
You can port with the valves in but stay away from them. It's very easy to slip and nick a valve stem. If you have a shop vacuum try to rig it up to evacuate some the shavings while you are porting.

What type of gaskets are you using as a template for the final port size? The Felpro performance exhaust gaskets have very large ports, so I wouldn't suggest those. I simply used the Mr. Gasket gaskets that came with my headers. For the intake side, the Felpro Performance P/N 1250 is very common. Edelbrock's intake gasket P/N 7220 is identical in shape and size but is made from materials that are much better suited for an every day street car.

Have fun and Best Regards,
Mike
I have procomp motor sport gaskets
I know Procomp simply copies other manufacturers' parts and has them made overseas (China). But I am not familiar with their gaskets. If they are a copy of the popular Fel-pro 1250 for port size that is great. What are you using for an intake manifold? Is it a Procomp as well?

Best Regards,
Mike
procomp all around.
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