Springfield Flyer.

[tauruck]

Sparky, here's some 351C stock 4v heads.

[tauruck]

It's a common mod on a Cleveland, you can buy the plates here & Aus.
  Sid.
https://www.google.com/search?q=Cleveland+exhaust+plate+modification&biw=1260&bih=599&tbm=isch&tbo=u&source=univ&sa=X&ei=JccaVYnlPM-zoQSmq4GIAw&ved=0CB0QsAQ

Hey Sid, lots of big HP increase numbers were thrown around about the high port plates.
What do you think taking the dog leg out does for the ports increase wise?.

[kiwi belly tank]

I know some guys tried that back when I was out running them with my 5 liter (302 Cleveland) Hydroplane in Aus but I don't think it achieved anything because they gave up on it & the fact you're boosted ( well at least your engine is ) I wouldn't mess with it. I always found more power with a rough port finish over a polish too & be generous with the radius in the valve pocket. I have a healthy respect for the Cleveland engine.
  Sid.

[tauruck]

When Jack Roush was doing the mod on his Pro Stock motors I heard 100HP?
Sounds a bit much but what do I know.

[kiwi belly tank]

When Jack Roush was doing the mod on his Pro Stock motors I heard 100HP?
Sounds a bit much but what do I know.

Without a flow bench, a bunch of heads & a bunch of time it's not a wise place to go so if you need more you can turn up the boost.
First on the agenda, keep it simple, get it to make passes & then go looking for more.
Are you addressing the oiling shortcomings?
Do you have Ozzy blocks down there or US blocks?
  Sid.

[tauruck]

My port plate blanks were made in 02 for my "Roush" motor I was going to build.
The heads were milled years ago.

We have a weird situation here on blocks. Both thinwall casting and the Ozzy HD stuff.
Guys restoring Mustangs to original want the American thinwall blocks and the good stuff no one wants.
According to all the info the blocks that came out of my XB Utes (Rancheros) are truck blocks.

Mine are all Ozzy and yes I have to oiling situation handled. Got all the parts ready to go.

[SPARKY]

Thanks that is easy enough to see how that came about.

[tauruck]

Got three of the four plug recesses done but was too tired
to complete the last one. Plugs fit with the socket and boots have clearance.
Final tweaks when I bolt the heads to the block.
Things mover around a little I guess,

[tauruck]

A few more pics.

Should have the last one done in the AM.
It's pretty close.

I used Dykem spray through the exhaust ports so all four
blank areas on the plate should be marked.

Let's see how tomorrow turns out.

[Dynoroom]

I did the same thing to a 427 FE head. Lots of work for little gain.
I don't think the mod on a Cleveland would be worth 100 hp, 30-35 maybe........

You also might want to look at putting the Cleveland heads on a Windsor block, it takes some water mods but in the end it's a better block and has more racing/performance parts available for it. Like the dry sump mounting, previously mentioned distributor, etc...
 

[tauruck]

Thanks Michael.

My mate/mentor over here Derek builds those Clevors and I know them well.

I'm stuck with Ozzy "truck" blocks, stubborn and underfunded so I'm going to have to run what I have.
I'm a Cleveland lover.

I see you used something we call Devcon to seal the port plates to the heads.

You did a really neat job.

[tauruck]

I made some progress on the port plates today.
All four spark plug recesses are done and just need a polish.

The first exhaust port took a few hours with the die grinder but it looks good
so far.

My flange is actually stock I had of Sportster exhaust parts. It works well and is the right size
on the step for the stainless tubing.

[tauruck]

More hand shaping.

[tauruck]

The blue will all be gone once I've finished polishing and the plates
get a lick to clean up on the mill.

New ports blended in well with the head portion.
Some small issues but I'm pleased.

[fordboy628]

Looks good Mike.

Figure 30/40 bhp N/A * your boost pressure.   Stay conservative.

 
Fordboy