For god only knows what reason, I find myself once again building another set of cast iron heads... If I sound bitter about it, it's probably mostly because as I sit here typing this I have a sliver of metal in my eye that refuses to come out. I'll be sure to include the cost of new safety goggles and the eye doctor visit next time I'm pondering cylinder head options.

Moving on, maybe someone can give me some input on a couple things so I can get these things finished up. For what its worth, these are the 452 heads I'll be throwing on the 413 so they will retain the stock size valves. I've been cleaning them up using the template kit and widening the runner above the short turn just a bit. Although I don't expect to get carried away, I was also planning on opening up the push rod pinch area and doing a quick match port on the intake. My questions and concerns at this point are...

1.) When using the Mopar template kits, it looks like most of the 60 degree cut gets removed from the bowl. Does this sound right? Is it critical to retain the 60 degree angle?

2.) With regard to opening the push rod pinch area, is there a general measurement for how wide you can go as a rule of thumb? The area seems a bit thin to me and I don't want to get carried away.

3.) Lastly, these are stock type valves with no back cut. I'm leaning towards adding a 30 degree back cut to them but haven't committed yet. Is the gain at low lift enough to offset the small loss at the higher end? I'm assuming yes but I know there are guys on here that have way more knowledge about this stuff than me.

As always, I appreciate the input guys. -Trent

I'm sorta in your same boat - 452 heads, stock valves. I just kinda went for it, no templates, first time I've ever ported anything. I read an older post on this topic that said the templates don't address what's actually needed which is the short side.

For the PR pinch I didn't go nuts with metal removal just more smoothing it where the intake runner meets the bowl. My concern is that I went too far and took too much away from under the valve seat. I lapped a valve in and I still have a decent margin. The margin looks chewed up in this pic but it's really not. The valve faces are pitted anyway.

I have no expectations for these I did it more as an exercise just to see if I could do it. I promised myself not to spend any money on these heads beyond new valve stem seals. Thankfully no metal in my eye yet.

A good rule of thumb for beginners is....... less is more.

These pics show all that’s needed for 259/193 cfm @.600 from stock valve size 346’s.

I could make 500hp with heads like this.

I’ve tested piles of diy BBM heads that have had way more work than this...... that flow in the 240’s.

I tried to exercise restraint but blew right through that roadblock.

Last fall I had some 452’s in the shop that had been ported elsewhere.

2.14/1.81 valves, and more porting than is what’s done on the 346 head above. Also, the 346’s were tested with old OE 2.08/1.74 valves.

Intake:
Lift——-452/346
.100—- 67.5/69.6
.200—142.8/142.8
.300—207.6/206.8
.400—240.1/236.6
.500—256.1/251.3
.600—260.6/259.9

Exhaust:

Lift——-452/346
.100—- 57.1/56.1
.200—-111.0/106.1
.300—-150.0/140.8
.400—-167.1/170.0
.500—-170.8/185.4
.600—-174.4/193.2

With 2.14/1.81 valves in the 346 head, it would be 265-270 on the intake side and over 200 on the exhaust.
Might need a bit more work at the pinch to get to 270.

Here’s a 346 with a little more effort and slightly bigger bowls.
Ferrea valves, still 2.08/1.74...... but with back cut:

Lift——in/ex
.100— 69.6/59.3
.200—138.3/104.1
.300—201.7/141.8
.400—246.4/169.1
.500—263.4/190.2
.600—267.2/205.0
.700—272.9/212.0

Many Years ago I did some 906's for a dragster, 260 cfm , not a lot of grinding but found water pretty easy LOL, start over.

260 out of the 346/902/452 head is really a piece of cake.
270 requires a bit more time & effort.
280 requires a lot more time & effort.

260-ish out of a 906 ends up taking more time than the later heads because of the extra work needed at the short turn....... and unless you’re fairly skilled and/or have access to a flow bench........ you may have trouble getting there.
270 takes a fair amount of ST work for me get to that level, and 280 even more so.

Between the short turn and the much larger guide boss, I’d say it probably takes almost twice as much time to get a 906 head to 275-280cfm than the 346/902/452 head.

I have a set of 906 heads on my never tough again workbench that went 9.80’s in my Duster 30 years ago. .030 over, TRW piston, stock crank 440. I’m thinking those ones are up there in air flow but I never put one on my flowbench

The backside of the guide in the bowl is where I broke through.

Yes there is thin place

Exhaust is not so thin

From the other side of the fence.......a couple weeks ago.......

Stealth head with improved valve job, and blended bowls & short turns(no work at the pinch, guide boss, or port openings)
No back cut.

Lift——-in/ex
.100—- 67.2/55.3
.200—-135.6/114.6
.300—-200.4/143.9
.400—-247.5/167.6
.500—-274.8/186.6
.600—-283.1/200.0

Just a hobbyist here. Ive cautiously done a set of 915 360 heads. The intake runners and bowls I removed only enough material with rolls and stones to remove the casting slag, lumps, flash and surface roughness and unevenness. Tear dropped the valve guides leaving their height intact. I didnt use a tool such as the Helgesen's E-Bar tool for the pushrod pinch but rather used the rotary stone and took down the as cast finish. Did same to exhaust port and bowls but added a polish to the them as well as the combustion chamber.

What I remember about my old '452 heads that tested 270/210...
- 2.14"/1.81" valves
- Originally "bowl hogged" for bigger valves
- Then "Brad Hogged" for a lot of hours in a below-freezing unheated garage*

IIRC, they were 240-250 / 180-190 before any "real" short turn work.

* I might still be blowing out cast iron dust from my sinuses after that experience

Yep thats it the customer was not happy with me, it broke through AFTER they were installed & hydrolock was the result, killed a rod & the block.

Ahhh..porting p0rn....

So, totally a DIY job here, a couple of stages (these were not my 1st set of heads to be ported, but obviously I'm no guru). Along with the pics I will post the flow numbers, be what they are (done at the same shop, by the same guy both times) I thought the 2nd set was awefully high for a factory head.

1) Alright, so this was the result of my 1st stage...


2) And here is the 2nd stage, basicaly did a both of work around the guide boss on INTAKE side only, slimmed it down to just a thin area to support the bronze guide and contoured the roof by removing a significant amount of that guide-to-roof transition


The results are:

LIFT I_1 I_2 E_1 E_2
0.100 67 67 57 57
0.150 99 102 79 79
0.200 130 138 104 104
0.250 162 175 125 125
0.300 189 205 140 140
0.350 215 232 152 152
0.400 235 253 160 160
0.450 253 267 167 167
0.500 262 282 172 172
0.550 261 291 175 175
0.600 248 283 177 177

Things haven't been moving along as fast as I would like them to but that's how life goes. As of this evening the "template" work on the bowls is complete, the short turns have had a small amount of work done to knock the sharp edge off as well as had the entry widend, the intake runners are gasket matched and the push rod pinch area has been opened up to 1". At some point I should think about calling it good but I'll probably give the exhaust port a little bit of love tomorrow. About the only other thing I'm debating about but will probably put off for now is bullet nosing the guide boss. I'm not sure that given the amount of core shift, potential to make a leak and what I assume to be minimal gains, that it would be worth it. I was originally thinking I may get these on a flow bench when I'm done and unfortunately, I think that's why I keep grinding on them instead of calling it good enough and moving on. Oh well, maybe I'll force myself to call it good by next weekend at the latest so I can touch up the valves / seats and put the the freaking things together finally. I'll keep you guys posted as I move along...

I’d bullet nose the guides.
Don’t go nuts though.

It’s easy and there’s no water there.

This is what I started with on the 346 head above: