Alright...so my DIY home porting efforts have been completed. The W2 Econo heads (810 open chamber casting) were NEW, I kept the original MP valve job (previously had the machine shop look them over as they installed the liners in the guides for 11/32" stem valves, they said the valve job was "fine" as-is).

Anyways, I then spent a few hours (quite a few to be honest) with the W2 MP porting templates, nothing crazy, just enough to remove the extra casting materials. The aim here is to just have a better flowing port as the car is a weekend river, not a racer, but of course engine performance matters to me.

So here are the flow numbers I got from a local porting shop (measured at 28" with the exception of INTAKE at 0.650 & 0.700" lift, those were done at 25" and adjusted):

LIFT - INTAKE - EXHAUST - E_TO_I_%

0.050 - 030 - 032 - 107
0.100 - 060 - 054 - 90
0.150 - 093 - 082 - 88
0.200 - 124 - 108 - 87
0.250 - 153 - 130 - 85
0.300 - 178 - 154 - 87
0.350 - 205 - 172 - 84
0.400 - 231 - 183 - 79
0.450 - 252 - 186 - 74
0.500 - 271 - 191 - 70
0.550 - 288 - 194 - 67
0.600 - 300 - 195 - 65
0.650 - 305 - 194 - 64
0.700 - 292 - 194 - 66

The Exhaust was done w/o a pipe, but I did ask him to check a couple of spots and got back a 226 cfm @0.600" lift reading.

Truth be told I am not sure what to make of these numbers.

My old factory '596 castings (although heavily worked over with a much better valve job - multi angle) actually beat these all the way up to 0.600" lift, where the W2 then fly! The same guy who measured my W2 did my old '596 castings (flow numbers), and he did recall how well those ran.

OK, but who cares about the TOP flow reading, I care about the flow numbers at lower lifts, basically that "area under the curve" thing, and with my hydraulic roller cam with a .584 lift I'm not going to be benefitting from that 0.600 & over flow.

So I'm curious about a couple of things:

1) the numbers as they are, what do you guys make of them?

2) should I actually do a performance valve job on these heads? (OK, I know that sounds "silly" now, but the machine shop that did the liners install did look them over and I had no reason to think otherwise)

- the porting guy said: you are losing flow at low to med lift with this valve job, he can do a multi-angle seat cutter pass that will clean up the current seats

- measuring the valve seat lap markings you can actually tell that the diameter of the valve head that's actualy being utilized is not 2.02 but rather about 1.94, so the head seat is just a tad narrower which means it's not taking advantage of the full valve head diameter

OK, that's it. Attached are a couple of pics of the results, as always, I appreciate all the feedback!

The first thing I noticed and don’t like is the .300 lift number. I have a hard fast rule saying if I don’t have 200cfm@.300 lift it’s not going on my engine. That’s with any aftermarket small block head. I care about that number more than my do .700 lift because I can build from there. A nice valve job would probably help.

It needs a better valve job in my opinion, I've seen up to 30 cfm across those low lift numbers. Low lift is all in the valve job up to approx .25 valve dia.

I agree with the first two replies. PBR’s .300 lift rule is worth following. And that valve job needs work. I know it doesn’t have a top cut, or at least a good one and that a huge deal.

And you would have see a 2.08 valve. 2.02 is small for that port.

Do you have before #'s on the same flow bench ?

Nah, unfortunately I do not.

I initially had the heads at another shop that does have a SF-300 bench and we were going to do a step-at-a-time "do and check" kind of a thing with these. But after waiting for months and never having been able to get any traction at that shop I gave up and just went my DIY route.

So I do have the "new in box" numbers on that SF-300 bench, but it's not the same bench as these last numbers, here they are:

LIFT - INTAKE - EXHAUST - E_TO_I_%

0.100 - 066 - 074 - 112
0.200 - 120 - 135 - 113
0.300 - 160 - 170 - 106
0.400 - 203 - 186 - 92
0.500 - 234 - 200 - 85
0.600 - 252 - 200 - 79

What you can tell here though is that while the INTAKE side does seem pretty reasonable, the EXHAUST is actually higher in as-is shape than it is after the porting work. Not saying that's wrong, but the casting flash in the as-is port really narrowed down the throat area, meanwhile the porting work simply removed that excess material and barely touched the bowl itself, so no actual reshaping of that area.

Alright, thanks for the feedback everyone!

In hindsight I should have gone with a 2.05" valve to start off with and a real valve job as opposed to leaving these as they were.

I am in a bit of a pickel now b/c my valvetrain geometry kit uses the current 2.02" valve size and going to a bigger valve now would negate the fit of that kit.

I will look around to see if I can find the same length valve though, but not likely...LOL

In the meantime, the current flow bench guy who suggested that I should really do a valve job says the following:
- 4 angle job
- blend in to a 3 angle after
- do a backcut on the intake valves

So that'll be the plan for now. I'll update with the new flow results as we finish that work.

It’s pretty obvious by looking at the exhaust flow curve(ex numbers with 1.6 valve are higher than intake numbers with 2.02 valve thru .300 lift) there’s some sort of problem with the bench/test.

As for the ported numbers from the second bench........ I wouldn’t be happy with how poor the .200-.400 intake numbers look......... if the results were the same on my bench.
Of course....... the curve could look completely different on a different bench.

If you stay with the same length valve your geometry kit won’t be affected. Go for it. Personally I would go 2.08 but that’s me.

pittsburghracer, everyone...


So strangely enough, I was able to find two Manley valves that literally are a drop-in, well, just about, here is why:

1) CURRENT valve - 2.02", 11702-8, 5.240" long, Severe Duty Pro-Flo

2) ALT_1 - 2.055", 11556-8, 5.240" long, Race Pro-Flo

3) ALT_2 - 2.080", 11574-8, 5.240" long, Race Pro-Flo

Now both ALT_1 & ALT_2 are not a Severe Duty valve material, they are the immediate step-down from that, which is the Race stuff (so says Manley catalog).

This being a street car, i.e. prolonged idle and low-rpm operation, therefore more heat, do I need to worry about the valve materials?

Also, is the idea of tossing a 2.080" valve in there a little crazy - given my intended use? Seems like a tight fit as well, no? Do I need to start looking at de-shrouding the chambers further (they have some light clearancing done rigth now)?

The 2.08 valves in my Edelbrock heads are on a .030’over 360 and have cleared on SRP pistons, Wiseco pistons, and Diamond pistons with zero issues but is something that needs checked. When upsizing valve sizes the throat under the valve seat needs checked for proper sizing (89-91 percent for most applications). Usually easily done when going with a 70 and 60 bottom angle.

See above in Red

If your valve job is effective, you'll be looking at 320cfm so a 2.08 would be beneficial.

I worded this poorly...I agree, the larger diameter valve will not cause a problem, and what I really meant is that finding a larger diameter valve may not give me the same matching length valve that I have right now.


Correct, Econo heads, the Manley 11702 valve I have right now is 5.240". As it happens I was only able to find Titanium Ferrea valves in that length, didn't spot any stainless in 5.240" though.


Well, if I am going to spend the money on a new valve job, as much as I hate the thought of delaying the project even further, in the big scheme of things this is nothing...so I best start shopping around I think!

Well, if I am going to spend the money on a new valve job, as much as I hate the thought of delaying the project even further, in the big scheme of things this is nothing...so I best start shopping around I think!




I often see guys looking for stock length 2.02 W2 valves so they have a nice resale value.

and for the "stoopid old man question of the day"................

should one look closely at the .300-.500 [mid ?] lift flows to see how much gain one can get there, as the engine spends a lot of time [especially if used on the street any ?] there ?
i hope i asked the question the way i intended, or as i understand it.
please don't hold this against me if it is not relative to the thread.

Any head porter starts out aiming for the big number. But if I know what cam the customer is going with that’s where the gold is. .700 lift doesn’t mean crap if he’s running a .550 lift cam. .300-.600 pays the dividends.

And no that wasn’t a stupid question.

thanks John.
over the last year, i find myself forgetting more and more things i should know by heart !
it sucks getting old ! well, the forgetting part at least.....

Well...I "chickened" out...so to speak. More of a "what can I trully do today to meet my goal" actually, the goal being: fire up the motor before the season is completely done (southern Ontario here, think Detroit, MI - as that is literally just across the river from Windsor).

Anyways, I decided to stay with what I currently have, that being the Manley Severe-Duty intakes. The 2.05 and 2.08 stuff is the Race series, and I just didn't have the comfort (nor readily available stock) to take the plunge.

Alright, so where are things right now?

Well, the shop did the multi-angle valve job and valve backcut, the numbers in the low to mid range improved anywhere between 9 to 15 cfm, but the high-lift stuff gave up a bit 305 => 291 @.650.

So here are the NEW numbers:

LIFT - INTAKE - EXHAUST - E_TO_I_%

0.050 - 039 - 032 - 82
0.100 - 066 - 055 - 83
0.150 - 100 - 089 - 89
0.200 - 132 - 111 - 84
0.250 - 165 - 137 - 83
0.300 - 192 - 157 - 82
0.350 - 217 - 173 - 80
0.400 - 244 - 186 - 76
0.450 - 267 - 192 - 72
0.500 - 277 - 197 - 71
0.550 - 291 - 200 - 69
0.600 - 294 - 200 - 68
0.650 - 291 - 200 - 69
0.700 - 288 - 200 - 69

I've attached a visual chart comparing a stock W2 long-valve head (MM Dulcich article since those were done on a SF-600 bench, which is what this shop uses as well) to the DIY1 porting results, followed by the valve job. Tossed in there are my old factory '596 castings as well, which were flowed by the same guy on the same bench.

Looking for some suggestions guys as to what else to focus on to unlock a bit more of that low-mid lift flow.

I haven't touched the short-side for obvious reasons, even the MP templates still show it excessively high with a very pronouned casting bump/ridge in the floor. I think I should remove that.

Beyond that, I could raise the roof a bit as per the templates, not much, but looks to be about 0.100" that could come out. The materials seems to be there to do this, but I was worried about cutting through to the head bolt passage.

Otherwise removing some material from around the guide humps is just about the only area left on the intake side.

In the exhaust port on the other hand, can I flatten the bump in the roof that's right above the guide? Seems like that could go because to each side is a lower placed (as-cast) channel, so I'm assuming the extra material there is meant to better support the valve?

I've added a picture of the exhaust ports showing that roof bump.

On the very same note, the flow guy suggested that I could square the roof on the exhaust port, basically gasket match to the TTI header gasket (which is what the square looking outline is from). Is this worth pursuing?

It is so hard telling someone on the internet how to do things it took you years to learn. And I didn’t really learn till I started checking airspeed in the port. Looking at your numbers and how they fall off up top I’m betting your airspeed is crazy fast at the short turn. W2 have plenty of available space at “the pinch” but past there the floor goes up, the roof goes down, and the common wall goes in. So we are asking air going 400 plus foot per second to make a very sharp turn into the cylinder. If it can’t it skips the turn and crashes into air coming across the top of the port behind the valve. You can hear it. At least I can and I can’t hear crap. I wish I could tell you what needs done but I don’t want it to be misinterpreted and have you screw something up. Where you are now it’s going to run pretty nice. I’m at the track and didn’t reread this so I hope this makes sense.