Head Porting basics

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wigsplitter74

wigsplitter74

The Mopar Kid
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So I've got some X heads on my 360 that I'd like to port this winter when I change cams. I know there's a lot of smart porting guys on here so what do I need to know? Lay out the basics and school me on it, what should I use for bits? Am I looking for perfectly smooth ports or can a little texture be helpful?

Are there porting templates available for LA heads? I haven't had luck finding them. Thanks all, I look forward to learning some things here.
 
I'm interested also.
 
the main part to porting is flow think of your heads with water going threw them.and if you look under your valves you will see what i call a porch roof or a lip.taking that out and blending it in makes a big difference then gasket matching makes a big difference.and unless its an all out set of race heads 7000 and up i dont polish the intake side.arond the valve gide on a small block i grind into a V big blocks i take it out.its hard to tell you whow to do this job the first set i did i was told to thik of them flowing water.then had a man check them.that was about 150 sets ago.
 
Picture is worth a 1000 words...remember to leave the floors alone there is NOTHING to be gained there...The short side radius is very critical and best left to someone who Really Knows what to do.You can round it but laying it back is again best left to someone with experiance.
The guide boss...roof and cross section is what you should work on...

smallblock.jpg

sbex.jpg

sbex1.jpg
 
Thanks very much for the info Godfather, and thank you Rob R especially for the really helpful pic kinda gives me something to shoot for. What kind of bits and tools are you guys using? I know there's port and polish kits for sale in jeg's and summit or is it good enough to use some rotary file bits on a drill? Again thanks much for the info, it's appreciated and will defenantly be put to good use.
 
Rob R said:
Picture is worth a 1000 words...remember to leave the floors alone there is NOTHING to be gained there...The short side radius is very critical and best left to someone who Really Knows what to do.You can round it but laying it back is again best left to someone with experiance.
The guide boss...roof and cross section is what you should work on...

smallblock.jpg

sbex.jpg

sbex1.jpg
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Hey Rob, what do they flow and @ what lift?
 
Hey Rob, what do they flow and @ what lift?
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x2!

I'm just starting on a set of 1.88 that will have 2.02 in it before I'm done.
 
What you have to remember is that no two heads are the same because of core shift...about 1 in 10 is a good candidate to try and go over 230 cfm.And not every port will flow the same if you get within 15 - 20 cfm your lucky.
I did those heads a few years back and I think the best port flowed just over 250 I seem to remember 238 (lowest) and 253 (best) cfm @600 with the bulk of flow happening between 350 and 600 and the ex flowed between 155 and 170 something.
I didn't want to get too thin as this was for a street car with an Engle solid roller RK48.It's a fairly fast lobe that sets the valve down kinda hard.
 
Rob, You can get 250's safely out of any j head, it's when you go for flow and port volume that you need to be careful.
If you check my profile you'll find more pics of the port work I do for my own engines.

Photo 200.jpg
 
Rob, You can get 250's safely out of any j head, it's when you go for flow and port volume that you need to be careful.
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So were is the spot to be careful when porting.......I know the bump in the roof(head bolt boss) you have to be careful but here else..........specially if there is a core shift in the port...........
 
fishy68 said:
Yeah that one and the pushrod pinch area.
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You can feel and eye ball both of these to know when your close...............Its the hiden water that i don't want my grinder to find!. :read2:
 
If this is a "first attempt" you can go wrong very easilly messing with either of those two areas. You wont get 250 from them either, but you may end up with a wicked cool looking port that doesnt flow for crap. Less is more in any event. Concentrate on the port roof and bowl areas, and I wouldnt touch the guide boss yet.
 
hey guys, this is a pretty interesting topic...how much can he expect to pick up from a mild port job and port matching everything? (in the quarter mile that is, or horsepower numbers roughly)...and wigsplitter, what cam are you going to run in it? i dont want to hijack the thread but what is the max lift cam you can run with x heads?
 
Like Justin mentioned, careful with the short turn and laying it back.

There was a pretty good porting story in one of the mopar mag not long ago.
http://www.popularhotrodding.com/en...dcore/0602em_cylinder_head_porting/index.html

Read about the "Venturi Effect" which will help with some understanding of the bowl area and valve seat relationships.

It's fun, dirty work on iron heads. Eye and breathing protection, good lighting are required. You'll smell rust for weeks and look like a rusting silo when taking a shower. Your shower will get trashed if not careful.

Here are the burs I buy from McMaster-Carr
1 4324A27 1 Each 1/4" Shank Extra-long Carbide Bur, Double Cut, Trade No. Sd-1l6, 1/4" Head Diameter
2 4324A24 1 Each 1/4" Shank Extra-long Carbide Bur, Double Cut, Trade No. Sc-1l6, 1/4" Head Diameter
3 4324A25 1 Each 1/4" Shank Extra-long Carbide Bur, Double Cut, Trade No. Sc-3l6, 3/8" Head Diameter
4 4324A32 1 Each 1/4" Shank Extra-long Carbide Bur, Double Cut, Trade No. Se-3l6, 3/8" Head Diameter
 
Why the double cut and not the diamond cut?

Whats better with the double cut?
 
mshred said:
hey guys, this is a pretty interesting topic...how much can he expect to pick up from a mild port job and port matching everything? (in the quarter mile that is, or horsepower numbers roughly)...and wigsplitter, what cam are you going to run in it? i dont want to hijack the thread but what is the max lift cam you can run with x heads?
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I'm planning on running a Comp Cams 507/510 lift that I can't remember the duration of right now, I think 24X. I'm not real sure what the max lift is for X heads, but I think I'm alright with this cam. Not sure tho.
 
wigsplitter74 said:
I'm planning on running a Comp Cams 507/510 lift that I can't remember the duration of right now, I think 24X. I'm not real sure what the max lift is for X heads, but I think I'm alright with this cam. Not sure tho.
Click to expand...

sounds good! good luck with the porting...i would like to upgrade my cam sometime in the near future to something in the 530ish lift range, but im not sure if the x heads, even properly prepped will handle it as im not sure what the max lift they can take is...anybody?
 
mshred said:
sounds good! good luck with the porting...i would like to upgrade my cam sometime in the near future to something in the 530ish lift range, but im not sure if the x heads, even properly prepped will handle it as im not sure what the max lift they can take is...anybody?
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Xheads will handle it, mildly ported they'll flow 230-245cfm and will go as much as any j head in ported form.

I like the Xhead exhaust floor, it seems higher in comparison, but it could just be the castings I have.:read2:
 
Heres a good start for you. Joe Mondello was the head porting guru for Olds for a long time.
http://www.mondellotwister.com/ArtHeadPort.htm

If you really dig on an internet search you may find some good info. Porting isnt hard. You need a steady hand and lots of patience. Let the right tools do the work,dont force it and walk away when your tired.

Taking metal away in the right area is key. It's the reason good porters dont share that info,as it's the result of countless hours spent porting and flow benching.

If you have a known "good" set of ports or heads to copy thats the best way to learn.I lucked out when buying the last set.They have a cnc ported exhaust and intake I can copy over to the other ports.
 
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