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Discussion Starter #1 (Edited)
So somehow a machine shop that has been in business 30+ years managed to screw up my lower intake manifold so badly I’m going to need to get a junkyard one. Looks as if he didn’t measure a damn thing and just cut it up as quickly as possible.

I told him when I dropped it off that the head ports are a slightly smaller than the gasket to which he said that’s fine and there would be no issues. When I picked it up we got talking and then he claimed the heads needed to be matched also and he told me to taper the head openings and go slightly larger than the gasket opening. Basically instructed me to go over the gasket boundaries.

What kind of issues will this cause because I’m just now finishing up one port on my recon heads and seeing everyone say under no circumstances shall you over step the scribe marks for the gasket.

Good news is I’m seeing a lot of folks online who have used devcon and jb weld to fix cylinder heads, and given I’m not in the combustion chamber or coolant jacket it should work just fine.
 

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Discussion Starter #2
After doing some research I’m gonna slightly close the port up with jb weld high heat and make the opening slightly smaller then the gasket to accommodate for the squish of the sealing rubber.
 

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The best way to "port match" intake and exhaust ports on heads is to....

#1- clean up the head surface for intake and exhaust ports
#2- use some sort of paint or "blueing compound/paint" on all the ports (intake and exhaust)
#3- once the bluing or paint is dry, lay the intake gasket directly over the ports and then using a "scribe", scratch around the ports(using the intake and exhaust gaskets as a guide (when you do this it's a good idea to "bolt down the gaskets so they won't move while scribing).

Once you have the patterns SCRIBED, using a good electric or air-powered die grinder and approiate cutting bit to enlarge the ports to match the inside dimension of SCRIBED PORTS. When you do this, you will want to grind no larger than scribed lines. Grind into the ports angled to match port walls. I usually go in approx 1/2 inch and nicely taper it to blend together with head ports. This has always been the best way to port match.

Now if you are looking for some extra performance during this process, you may want to consider going to a "cylinder head" shop and have to ports enlarged and polished/tapered all the way inside the port down to the valves. THIS IS NOT A JOB FOR SOMEONE WHO'S NOT FAMILIAR WITH THIS
PROCESS.

Best of luck, Jake
 

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Discussion Starter #5 (Edited)
Yeah I’ve decided to go with a port match and polish. Leave head ports the factory size and port to lower out to 1.90x.90 and put an 80 grit finish on both. I’ve already began porting and polishing the runners. Just taking out enough metal to get rid of the casting marks.
 

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Discussion Starter #6 (Edited)
This is done with nothing but sanding drums and cones. I’ve got an inside caliper on the way as well as a vernier caliper and telescoping guages so I can measure everything when I’m done and duplicate it on the other ports.
 

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This is done with nothing but sanding drums and cones. I’ve got an inside caliper on the way as well as a vernier caliper and telescoping guages so I can measure everything when I’m done and duplicate it on the other ports.
You may not need all the measuring equipment as you look like you have a pretty good eye.

I did mine from start to finish, with shape the way I think will flow ok.
 

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Discussion Starter #11
Not so much a good eye (I have been able to eye a few hundredths difference on the lower) as much as it is research and good help. Had a member of a 3800 group on FB send me pics as he was porting his own heads. 800hp turbo build. I’m just taking out enough metal to get rid of casting grooves and blending the rest of the runner and bowl into that. Biggest that I read online was you need tumble in the ports and swirl in the bowl, and imagine the air flowing through both. Biggest mistakes seem to be folks leaving pockets and concave areas which hinder flow.
 

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Discussion Starter #12
And what grit did you use on the exhaust ports? I’ve decided not to port mine or de burr the CC but I’m gonna polish up the exhaust with 320 grit
 
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