273/318 Heads

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DentalDart

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So I want to try my hand doing an at home port job on my Xheads... I found some 273/318 heads for 40 bucks, are these pretty close to the xheads to practice on?

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X heads are large port open chamber, what you have there are early small port closed chamber heads. I'd practice on something else. 65'
 
Those are early closed chamber heads. I would not mess them up.

X heads are large port open chamber, what you have there are early small port closed chamber heads. I'd practice on something else. 65'

I dont have anything to practice on... these are just some I found for sale locally and thought they would be better to mess up than my Xheads.

I dont know what open vs closed ports/chambers means, ill have to do some reading on them apparently.
 
Practice on junk. Go to pick n pull salvage yard get junque to port if you want to practice. Closed chamber refers to the size of the combustion chamber where the valve faces are. Closed chamber means small combustion chamber space it this area where open chamber this area if Yuuuuge and equates to low compression. Circled part is "the chamber". Open chamber refers to this part of the head having a lot of CCs of volume.

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Practice on junk. Go to pick n pull salvage yard get junque to port. Closed chamber refers to the size of the combustion chamber where the valve faces are. Closed chamber means small combustion chamber space it this area where open chamber this area if Yuuuuge and equates to low compression.

I was figuring 40 bucks was junk :rofl:
 
So I want to try my hand doing an at home port job on my Xheads... I found some 273/318 heads for 40 bucks, are these pretty close to the xheads to practice on?

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I wouldnt call those practice for a 340/360 head because the ports are diff. Ssr is much more 'know how' than a 318 head.

You can hardly fk up a 318 head. Why i dont charge but 250.00 to make them go 200-210cfm w/stock 1.78 and 144 exh..the $600 dollar special for a full reman 'stock parts' and port job on a 318/273 set.

Just get the x heads and we can walk you through a safe approach to pick up the flow. Mine go 271cfm@.550 intake and 199 exh
 
I wouldnt call those practice for a 340/360 head because the ports are diff. Ssr is much more 'know how' than a 318 head.

You can hardly fk up a 318 head. Why i dont charge but 250.00 to make them go 200-210cfm w/stock 1.78 and 144 exh..the $600 dollar special for a full reman 'stock parts' and port job on a 318/273 set.

Just get the x heads and we can walk you through a safe approach to pick up the flow. Mine go 271cfm@.550 intake and 199 exh

I have xheads, they are on my engine though. I just figured I would practice on something before diving right in... plus I'd be able to keep driving my car until confident in my "abilities." LOL

What is SSR?
 
I have xheads, they are on my engine though. I just figured I would practice on something before diving right in... plus I'd be able to keep driving my car until confident in my "abilities." LOL

What is SSR?


If you are actually a dentist, you ought to be able to port very easily. Not much different than grinding out a filling, or shaping a tooth for a crown or whatever.

I can grind with electric, but I don’t like it. I prefer air. I have some some burrs that are 3 inch shanks, but most everything is 6 inches. Use whatever cutter it takes that makes your heads shape the port the way your eye sees it. There is not a wrong cutter to use (most of the time) if you get the shape you want.

SSR is Short Side Radius, and it’s also called the short turn. It’s the floor of the port where it turns into the bowl.

I don’t think those heads have any value, but I don’t think any of that style of head has any value. I may very well be wrong.

Whatever you get to grind on (it can be GM junk...it don’t matter what name was on the valve cover) you need to learn to make the shapes you want. Once you master that, you can port anything.

If you don’t have a sonic tester to see how thick some of the critical parts of the heads are, drill some small holes in the head where you want to see section thickness. That’s as important as anything else.

Once you start grinding, grind through a bunch of spots. Learning to see when the metal is getting thin can only be learned by doing it. Much better to learn on junk than a head you want to use. Cast iron isn’t nearly as easy to weld as aluminum.

Porting is about shape as much as it is about size. Almost every exhaust port is way too big already, so making it bigger is a power loss. Air like another fluid HATES to change direction AND it hates changes in cross section. If you are going to make air go around a corner, you better know why, and do everything you can to make it happy air as you force it to change directions.

Same with changes in cross section. Taper isn’t the same as cross section changes.

You can’t learn to port without doing it. Reading some good books helps, but you have to do it to learn it. Don’t be afraid to make mistakes and grind through places and get a look at it.

It’s a dirty, thankless job.
 
It can't be that hard to find a set of "J's" or any other 360 head with a cracked seat to practice on.
Try asking around the local engine rebuilding houses or machine shops ask for cracked or dropped valve heads they make great practice heads and don’t forget about dissecting them to look at material thickness and water jackets. Just my 2 cents.
 
If you are actually a dentist, you ought to be able to port very easily. Not much different than grinding out a filling, or shaping a tooth for a crown or whatever.

I can grind with electric, but I don’t like it. I prefer air. I have some some burrs that are 3 inch shanks, but most everything is 6 inches. Use whatever cutter it takes that makes your heads shape the port the way your eye sees it. There is not a wrong cutter to use (most of the time) if you get the shape you want.

SSR is Short Side Radius, and it’s also called the short turn. It’s the floor of the port where it turns into the bowl.

I don’t think those heads have any value, but I don’t think any of that style of head has any value. I may very well be wrong.

Whatever you get to grind on (it can be GM junk...it don’t matter what name was on the valve cover) you need to learn to make the shapes you want. Once you master that, you can port anything.

If you don’t have a sonic tester to see how thick some of the critical parts of the heads are, drill some small holes in the head where you want to see section thickness. That’s as important as anything else.

Once you start grinding, grind through a bunch of spots. Learning to see when the metal is getting thin can only be learned by doing it. Much better to learn on junk than a head you want to use. Cast iron isn’t nearly as easy to weld as aluminum.

Porting is about shape as much as it is about size. Almost every exhaust port is way too big already, so making it bigger is a power loss. Air like another fluid HATES to change direction AND it hates changes in cross section. If you are going to make air go around a corner, you better know why, and do everything you can to make it happy air as you force it to change directions.

Same with changes in cross section. Taper isn’t the same as cross section changes.

You can’t learn to port without doing it. Reading some good books helps, but you have to do it to learn it. Don’t be afraid to make mistakes and grind through places and get a look at it.

It’s a dirty, thankless job.

"Actually a dentist.." Made me lol. I will be in 5 months... Dental handpieces (drills) are much smaller than any electric/air drill I have ever used, but I am sure if I could get some good purchase points for my fingers I could make some pretty awesome cuts I would assume (?), just cant add metal where I take to much away right? lol.
 
"Actually a dentist.." Made me lol. I will be in 5 months... Dental handpieces (drills) are much smaller than any electric/air drill I have ever used, but I am sure if I could get some good purchase points for my fingers I could make some pretty awesome cuts I would assume (?), just cant add metal where I take to much away right? lol.


LOL...I knew you either already were or were close to getting it done. Adding metal is problematic for sure.
 
What's the casting numbers? You probably could sell them before the end of the month here.
 
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