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If max low/mid lift flow are your priority, buy the bare heads, recut intake seats for 2.055 valves, leave the bottom angle long, keep the bowls/throat as small as possible, back cut the valve.
For the intake side I'd use: 46 at .080 wide 50 at .045 wide 65 at .110 wide 75 at .110 wide 80 at .200 wide I can't find the exhaust cutter I'd use but it would be a 50 seat with a 44 degree top cut .120 wide and a radius off the bottom of the 50. The exhaust is going from memory but that's pretty close. And as PHR said earlier, I'd sink the valves until the top cut was all the way in. I'd try and use a 2.02 valve if possible but nothing bigger than a 2.05 if I couldn't get that valve job in there with a 2.02 valve. Edit: forgot to mention the exhaust would have a fairly large tulip to it and the intake wouldn't be a nail head. And if I could avoid it, no back cuts.
For low and mid-range lift you should enlarging the Uncommon wall.. lengthen the short side.. add some material around the bowl... Forward cut the back side... reradius the radius.. and don't forget to bring the roof to the floor and the floor to the roof......
I'm a bit apprehensive about running a 50° seat in such a flat chamber, one would have to sink the seat quite a bit to get this profile. But I'd love to try it.
LOL. Me too. That flat chamber always makes me nervous BUT, even with a decent 45 it's damn hard to get a good, full top cut in there without sinking the valve. Used to be when someone said "sink the valve" anyone standing there would go apoplectic, lose all the color in their face and then they'd call a priest in to do an exorcism on you for speaking that voodoo. Skimping on the top cut is a no no. But yeah, the flat chamber makes me nervous too. As PRH so well says...iiwii and that's about all you can say.
[QUOTE="yellow rose, post: 1972786972, member: 41803" Used to be when someone said "sink the valve" anyone standing there would go apoplectic, lose all the color in their face and then they'd call a priest in to do an exorcism on you for speaking that voodoo. .[/QUOTE] Ain't that the truth. Then you try to explain the virtues of seat profile vs seat height and they stare at you like a deer in the headlights.
Ain't that the truth. Then you try to explain the virtues of seat profile vs seat height and they stare at you like a deer in the headlights.[/QUOTE] Yeah...and now you made me rethink my decision. Then I started thinking that no matter what you do, the exit loss at the valve because the chamber is so flat is going to be bad no matter what you do. So I guess I'd rather have the seat/throat/bowl shape I like and live with a bit more exit loss than try to change the seat to try and clean up the mess after the charge gets around the valve. It's funny...when you look at the TF chamber, and then look at the newest stuff in chambers and you don't see many chambers that are what used to be considered "hard" compact chambers. They are moving towards a much "softer" compact chamber (like the TF) because it still has the same ignition timing requirements but that hard chamber has a much tighter tune up window, among other things...
You guys carried the banner well today so after church I stayed housebound. Lol. You guys make valve jobs way to complicated.
No problem I did what I could now you can continue...
Ok guys I finally got this head back on the bench to flow the exhaust after what I call shaping work. As I told you guys before I was told by a head guru (Darren Morgan) that speed on the exhaust side was more important than flow so who am I to argue. (Target as close to 325 as I can get) Again I am super impressed by this exhaust port and how quiet it is so I said to myself let’s not get stupid so I stuck with the valve job as it came from Speedmaster. A 60 degree cut and a 45 seat. Airspeed before after just chamber work maxed out at 270 (very nice number). Tonight after porting max airspeed was 332 FPS. DAMN!!!!
Holy sh** Batman! That's bookin'!
I am still trying to grasp the concept. (in my pea sized brain) LOL All of a sudden the light bulb will come on and I'll yell "Now I get it" LOL I haven't looked but too bad there isn't some videos to show the mixture path through the intake, into the head, chamber, and out the exhaust and what modifications do for the flow in positive and negative ways. One of you guys mentioned the short radius and how you feel it with a finger and can tell if it's good ot not. Now you got me doing it! LOL
Flow numbers ———-stock——-ported——-gain .100——-34————-40————+6 .200——-95————104————+9 .300——-135———-143————+8 .400——-159———-175————+16 .500——-172———192————+20 .600——-179———202————+23 .700——-181———207————-+26 .800———————-210 I never flow these ports this high as they are usually stalled way before I get this high.
You have looked at a lot of ports. Can you figure why these are so good?
I have an unmolested Edelbrock Head here. Not today but I’m going to do some snap gauging and side by side fingering soon. I got a 408 I gotta dummy together to check a few things here soon so I can get the assembly out to be balanced so I gotta hop on that soon.
Ohhh well back to the flowbench. I really didn’t want to get sucked into getting crazy on these but I gotta give the intake side one more attempt before I throw them on a shelf. I’m at 202@.300 but only 278@.700 lift. Floor work needed but it’s begging for a 2.05 valve.
And.............were off!!!!!! The needle is in! You can't stop now...there is more there... You know I'm right!! Now you have to keep working on them to see what Max is!! Porting is almost as nasty as habit as heroin is. Once the needle is in....
When it comes down to it, those who go deep...end up at the floor. Iirr... in this very thread, a certain someone spoke against it. Fact is..the angles of approach are many and differ from others even... there is no set way and working floor is what it takes, leveling it across and evening up the distance..and lowering it sometimes. I had a guy in another thread talk a bunch garbage about it... and the sad thing about it is.... it was over a slant 6 head where there really isn't much material in the roof everything is mostly gained by opening the bowl and laying the short turn back far into the floor halfway or more of the port...then coming in the port window side and cutting straight in lowering the floor, ramping it down a hair..getting the line of sight. With any head.. there is a threshold...in order to breakthrough that threshold...you have to push harder and make area, even.. ..If the turn is shaped right...lowering the floor,to a point ,will only gain more flow IF its straightening the line of sight and more so feeding greater volume to the ssr..it really depends of course.. Many iron heads are just too small port volume wise.... anyways.. Great thread. I'm I'm trying to only check it out every couple days if I can I just want to see what happens with your progress and not read all the other crap from everyone else. LOL some of this stuff is just a repeat, people should know it, like some people had Amnesia or something. Not to vere off too hard on this but was it only a few months or year back people were really skeptical over these heads n now they're one of the greatest heads ever? Evolution...of the skptic..that's badass lol..
Wayyyy. 915 J 1971 casting 73@.100, 147@.200, 204@.300 249cfm@.400, 278@.500=3 angle valve job & 186 cc ,hard seats on int proud in the chamber. Most of the work in the roof ,widening the port , and leveling the floor before the turn...guide skinnied n left long. I pass on all those experimental / oddball seat angles. Longevity is more important to me and ultimately I get where I wanna go, just fine , without it. It's there if you search hard enough... I have spent a weeks time, conservatively here and there, on one port, in order to find it. Back cuts, sets angles...worth 4-9 cfm, sometimes... other times they speed the air and create a revisit somewhere else to correct the fall off. Gordon said it earlier in this thread, something like or about how to just get "close enough" to the goal, in some heads, is good enough...because that next move can sometimes bring headaches. You'll definitely find more in that head. You may.. or may not, trade 4 cfm 'down low' to see those 290's... I doubt it... but i know you have a good 12-15 cfm waiting on the next page for ya.
What's not reliable about a 50 degree seat? The funny thing is I know there are many guys out there doing some variant of a 50 on everything from street cars to their race stuff. I've used it on 2.3 heads, and last time I checked on that engine (mid December) that head is still the best they've come up with, and it's still the best on the dyno and at the track. And that's after Esselinger squealed like a stuck pig when the found out I was not only changing their valve job, but correcting their crap CNC porting. I know, for 100% surety, that I'm not the only one who doesn't pick a valve job based on lift. I know personally (through PM messages and such) that there are guys who are using some variant of a 50 on lift rule stuff. All under .500 lift. And it works. I've never been fond of doing R&D for free, but I've also never sat back and let technology go by without doing my own investigation. And making my own judgment. It doesn't take long on a flow bench to understand why steeper than 45 degree seats are becoming the norm. Irregardless of how much David Vizard and a bunch of other guys harp on low lift flow and flatter than 45 degree seats for less than .600 lift stuff.
^^^^^^ flow #'s ? velocity # 's ?
If flatter brings up the low lift and steeper helps the high lift, make sense I'm good at 45 cuz I'm not playing at 600 plus lift playground... everytime having to re face the 45 degree ootb valves,eh.. I'm okay not making it more complicated or time consuming. I dont doubt it can help somewhere, but nowhere I've seen.
Like I said...I don't pick a valve job based on lift. And I'm not the only one. If you're so concerned with low lift flow, you should follow DV and use a 30 degree seat. That's a sure fire power loser. But he seems to think low lift flow is the do all, be all, end all. It's not. Not even close. But he thinks it is. LOL...in fact, if you look at his porting book, his own writing contradicts some of the CFD work he published in the same book.