Intro to a port job

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Did some short turn work laying it back just a hair near the top and also worked the ssr floor hump off of the straight side wall, roof hump, straight wall some more till the push rod pinch 'still untouched' finally became an issue with air speed.... it was stuck at 235cfm@.500.... once I opened the pinch it went to 241.5 cfm and through .500 above.
I also pulled the valve and flowed it plugging the guide=238cfm . Its shaped to utilize the valve at the moment...har har .. aka 'showing how bad the valve job is' it actually needs the valve to turn around the seat. Anymore flow? imo its roof and guide that can squeeze a little more cfm...but the potential doesnt really warrant spending too much time, time is money...you must consider the return. Pics are not high quality, I snapped them in a hurry before i wrapped it up last nite...I'll take more and post them.

The current numbers.....increase in cfm
.100-63.5...........................27
.200-120............................30
.300-175............................30.5
.400-219............................32
.500-241.5.........................34
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Not scrap, but nothing to write home about.
The .300 is a direct reflection of the valve job I cannot change unless the owner decides to.
Stay tuned.

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Thanks much for the information once more. I am about to procure a set of 360 high swirl heads from a friends stockpile of HD Dodge parts, I am hoping to luck up find some early ones without the huge pushrod boss. Planning on the largest size valves practical to minimize the chamber volume and working the ports for maximum flow under the .530 lift range. This will be going on a 3.94 bore 318 (.050 over if I go to dome pistons). If you don’t mind my asking, what would be your recommend valve diameter and seat angles on a set of these heads that still have the factory cuts? They will be getting a Serdi radius job.
 
Garrett Ellison said:
Thanks much for the information once more. I am about to procure a set of 360 high swirl heads from a friends stockpile of HD Dodge parts, I am hoping to luck up find some early ones without the huge pushrod boss. Planning on the largest size valves practical to minimize the chamber volume and working the ports for maximum flow under the .530 lift range. This will be going on a 3.94 bore 318 (.050 over if I go to dome pistons). If you don’t mind my asking, what would be your recommend valve diameter and seat angles on a set of these heads that still have the factory cuts? They will be getting a Serdi radius job.
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1.94 valve diameter 11/32 stem 5.025 length.
90,70,45,35
3 angle is fine as long as they are right angles.
Find the spot between maxed bowl 90% and maybe a little small still like 85%, Finesse that last bit after the valve job if necessary so you can see better if need be.
 
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MOPAROFFICIAL said:
1.94 11/32 +.100 valve diameter.
90,70,45,35
3 angle is fine as long as they are right angles.
Find the spot between maxed bowl 90% and maybe a little small still like 85%, Finesse that last bit after the valve job if necessary so you can see better if need be.
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Thank you very much for your input. I was planning on 11/32 valves, did you mean .001 oversized stems? I know the exhaust ports & bowls are really strong on these heads, same three angle grind and bowl treatment?
 
Garrett Ellison said:
Thank you very much for your input. I was planning on 11/32 valves, did you mean .001 oversized stems? I know the exhaust ports & bowls are really strong on these heads, same three angle grind and bowl treatment?
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Fixed.

A radius under the seat works good with the r/t and 308 exhaust ports, but hard seats can make that difficult if the insert isnt ideal for such. With a j head type exhaust port you can just go straight up from the seat, as I do with these as well.
 
Update.
Tossed the 308 heads, previous valve job was disastrous to the performance potential. Though they flowed decent...way too much work to bring them all there and still be short of what it could have been. To find a new worthy casting...I waited .. and waited....and finally an old dodge b200 found its way to the local yard. I yanked the heads off of it the day after it showed up. Std 360 4 brl ,steel head gaskets... casting on under side of intake runners is 348915 and the foundry mark I've only seen on 308 heads. Will transfer all hardware/valves to these. Now....that's a digit short of 3418915 J . No letter on the plug side... and DO have smog exh port bumps. Strange and impressive for potential. Had flat face exh valves. Under the covers no numbers other than "74" "25 J" and a "..9?15.. Stay tuned .
 
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gliderider06 said:
Pardon my ignorance, or just plainly missing something here, but... what is the purpose of putting in larger valves in a head,(other than having new valves) if nothing is done leading up to that valve? I just don't see any gain at all in doing so.
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That is the problem with many shops and enthusiasts as well. They don't realize that to get the most benefit out of putting larger valves in a chamber, you also need to enlarge the bowl area proportionally. Even in a performance build without installing larger valves, the bowl area may still need to be opened up to meet the 80%-90% ratio many professional head porters like to see for bowl to valve size ratios.
 
Interesting thread. :) Im away to start porting a set of 587's that have been taken out from 1.88" to 2.02". They where fresh when I bought them, maybe 300 miles or something. Wish I was able to flow them though, would be amazing to see the progress on them.
 
trigger_andy said:
Interesting thread. :) Im away to start porting a set of 587's that have been taken out from 1.88" to 2.02". They where fresh when I bought them, maybe 300 miles or something. Wish I was able to flow them though, would be amazing to see the progress on them.
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There is a thread called "360 head trip"
360 head trip
It gives before numbers w/1.88 int valve and after some porting. Think they went 241cfm iirr. I'll fwiw flow one port before, I'm not gonna waste too much time flowing all of them before to find the highest, just one random on each head to show before and any variance. I WILL flow them all in the porting stage.
 
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MOPAROFFICIAL said:
There is a thread called "360 head trip"
It gives before numbers w/1.88 int valve and after some porting. Think they went 241cfm iirr. I'll fwiw flow one port before, I'm not gonna waste too much time flowing all of them before to find the highest, just one random on each head to show before and any variance. I WILL flow them all in the porting stage.
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Ok cool, I'll go search that up now. Im a complete amateur and have only played around with another two sets of 587's with 1.88" Valves. I have some pics but I doubt there would be much interest to see them. :D

Looking forward to seeing how this progresses.
 
MOPAROFFICIAL said:
There is a thread called "360 head trip"
Click to expand...

Ah just had a look at that thread. Thats what I based all my Porting on. :D Have studied that thread for hours getting to know the terminology and what can/needs done. Awesome stuff.

Wonder why he was banned?
 
trigger_andy said:
Interesting thread. :) Im away to start porting a set of 587's that have been taken out from 1.88" to 2.02". They where fresh when I bought them, maybe 300 miles or something. Wish I was able to flow them though, would be amazing to see the progress on them.
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Steve Dulcich has some HRM articles online showing how to port Mopar 360 smog heads to bring them up above a set of mildly worked X castings, it's a good read. Also, if you want to build a flow bench with a MAF unit and a seriously large shop vac (think car wash coin operated vacuum), check out the forum at flowbenchtech.com.
 
I believe this is the article you mentioned.
https://www.hotrod.com/articles/mopp-0002-porting-exhaust-smog-heads/
I'm in the middle of porting my x heads, and not a lot of X head specific info out there, so I refer to above link all the time.
Here is another link to x heads.

340 X Head Buildup - Mopar Muscle Magazine
Garrett Ellison said:
Steve Dulcich has some HRM articles online showing how to port Mopar 360 smog heads to bring them up above a set of mildly worked X castings, it's a good read. Also, if you want to build a flow bench with a MAF unit and a seriously large shop vac (think car wash coin operated vacuum), check out the forum at flowbenchtech.com.
Click to expand...
 
Yes indeed, that's the article! Got a set of 475 360 heads laying around that I want to victimize like that if time and $$$ allow.
 
Garrett Ellison said:
Steve Dulcich has some HRM articles online showing how to port Mopar 360 smog heads to bring them up above a set of mildly worked X castings, it's a good read. Also, if you want to build a flow bench with a MAF unit and a seriously large shop vac (think car wash coin operated vacuum), check out the forum at flowbenchtech.com.
Click to expand...

Cheers I'll have a look. :)

I continually kick myself but I had a set of X Heads a few years ago when I was Moparless for a while. Sold them as I never expected to get into Mopars again for a while. Keep in mind this is in Scotland where they dont grow on trees. Sold them for something stupid like $200. :(
 
trigger_andy said:
Cheers I'll have a look. :)

I continually kick myself but I had a set of X Heads a few years ago when I was Moparless for a while. Sold them as I never expected to get into Mopars again for a while. Keep in mind this is in Scotland where they dont grow on trees. Sold them for something stupid like $200. :(
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I paid 400.00 'ready to run' 20 years ago. Cheers
 
Roughed in some intake bowl/guide and roof kink work before they go for 2.02 seats /valve job. For those who like reruns...I'll flow one stock port on the other before I finish it and send them off. I may even flow one w/1.88 and all the pre work + mild short turn. Have done zero work on the short side.
I'll throw up a pic, it's not 'finished' work. This is just the 2nd phase...1st was clean and mag to make sure they arent door stops.. later I run a dull cutter to finesse it all.
 
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