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Head flow
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Author:  Valiant ute [ Fri Mar 31, 2017 3:55 am ]
Post subject:  Head flow
Hey guys looking for some help / tech info on past experience porting , valves & port flow. I have ported a friends slant a few years ago . It made 174 cfm @ .450" but the retainer bottomed out @ .470 . It had 1.70" & 1.44" 3/8 stem valves , basically no chamber work ( still had machineist ridges around valves ) but had extensive port & bowl work , to some people. But I didn't do much to the short end just the slightest roll over. The full weight vc valiant 4 door ( 1966 Aussie car ) it ran 16.0 @ 88mph with crappy headers, 4bbl 450 Holley marine carb , crappy redline 4bbl short runner in let manifold , comp .440/.440 sld cam, stock converter , stock 904 , 3.23 or is that 3.32 ??? .
Author:  Valiant ute [ Fri Mar 31, 2017 4:09 am ]
Post subject: 
Story is the car & engine was never tuned or set up the way I recommended , and every corner was cut & every dollar wasn't spent. So I believe it ran good for what it is. I'm so frustrated with not knowing what could have been . I'm going to throw my own budget build together . To me there's just some places that I just have to spend money. Head , headers , inlet manifold , dizzy , cam. Being in OZ there's not a lot of 2nd hand slant bits , parts & shipping from the USA are back to unaffordable pre 2008 prices.
Author:  Valiant ute [ Fri Mar 31, 2017 4:47 am ]
Post subject: 
Big $ parts I'll buy are Aussie speed long runner " hurricane " manifold, Aussie speed headers ( most probably 1.5" primary ) 500 eddy 4bbl , e yab hei dizzy, high lift , medium effort duration cam ie 216-224 , 108 - 110 cam. I'm thinking a Hughes cam , but that can come after I work out comp ratio.
I have a head in the shop atm that I have ported one chamber & set of ports. After much reading , I tryed a big effort in the deshrouding department , I took 2cc out of the chamber especially around the exhaust chamber wall & inlet of course. It maxed out a big bore gasket. I hooked into the bowls knowing 1.70 / 1.44 valve cuts will need to be well blended. I got a pretty smooth short end transition now & removed that terrible angle/hump in the inlet floor. Raised the top of the window .100" & blended that into the roof. I then slimmed the guide all around, but not crazy. There's really not a whole lot in the port it self. Similar effort in the exhaust . I have inlet & exhaust valve from a LS1 & getting that turned down to 1.70/1.44 & having 1/2" bronzemaganese guides fitted & turned down to fit Vitoria seals with .650" lift.
Author:  Valiant ute [ Fri Mar 31, 2017 5:24 am ]
Post subject: 
The shop is flowing a untouched port & chamber with std valves , then my port & chamber with std valves . ( with extremely pitted seats . Was most rusted chamber ) before the custom valve work starts. I plan on using bee hive springs & retainers with the 8mm stems. The benefits I see are 1 cost , 2 weight , 3 heat transfer through 1/2 guide , a small amount of flow from 8mm stem & nail head design. When I say cost most machine shops will have std 2nd hand LS valves & springs that they throw away . So free or real cheap , just paying for turning them down for length & head. Btw I'm hoping I get some extra flow with the 1.70/1.44 & extensive deshrouding , rather than going bigger in the valve. I then plan on bogging up the chamber as if I was welding it into a closed chamber kidney shape with quench pads on both sides of the chamber. Then reflowing it until I get the best balance of flow & smallest chamber volume ratio. That way it leaves me with few options . One : I increase the compression ratio with std Pistons . Two: gives me a opportunity to mill the block for more compression or change Pistons to suit certain requirements. Three: go the long rod & 2.2 or wiseco piston set up & go for a high comp quench head with water injection . Many options with custom Pistons .
Author:  Valiant ute [ Fri Mar 31, 2017 6:04 am ]
Post subject: 
My theory is maximum flow with leased rpm. By not over porting the port runners & using long runner manifold that will keep a good air speed with plenty of volume on tap. The 500 eddy for ease of tuning & primaries should help with throttle response , but still have plenty air/fuel supply on tap. With a decent valve size & well blended bowl & short turn & deshouded chamber should flow well at all rpm speeds & not stall & drop off after medium-high rpms. If a head can flow well upto or over .500" it should open the valve far enough to take advantage of that. & that where the mopar lifter diameter should play its part & push the aggressiveness a little bit . Combine that with aggressive but not to large duration cam & lobe separation . And now the bee hive springs come into play. As we get to the upper rpms if we can control the valves without flexing the pushrods the power shouldn't nose dive. That's my theory . I'm only a beginner but this how I see things . Am I on the right track??? Any help with porting heads theory or flow or any info on making slants perform , or correcting anything I have said that's wrong please feel free. Thanks
Author:  DusterIdiot [ Fri Mar 31, 2017 4:29 pm ]
Post subject:  Slow down...Food for thought... lots of...
Welcome to the board, take a moment to think through what you wrote before hitting submit, these posts just kind of rambled a bit and were hard to follow...

You have a lot of theory but need to look over some of the builds and absorb the information before setting out on the great adventure. Throwing a bunch your ideas in to the mix without knowing if the parts are going to work together as a team will leave you with an empty wallet and a sluggy build...
and it doesn't end there... your camshaft, intake, timing, tire and transmission choices can also affect if the engine is even going be best suited for the car as well....

Let's look at some things to put some perspective on it:
Quote:
It made 174 cfm @ .450" but the retainer bottomed out @ .470 . It had 1.70" & 1.44" 3/8 stem valves , basically no chamber work ( still had machineist ridges around valves ) but had extensive port & bowl work , to some people. But I didn't do much to the short end just the slightest roll over. The full weight vc valiant 4 door ( 1966 Aussie car ) it ran 16.0 @ 88mph with crappy headers, 4bbl 450 Holley marine carb , crappy redline 4bbl short runner in let manifold , comp .440/.440 sld cam, stock converter , stock 904 , 3.23 or is that 3.32 ??? .
174 at .450 is a lot of flow...but here again, you picked a cam that had shorter duration that didn't allow the smaller ports time to breathe and fill the cylinder better... the intake on a slant is a bit lazy on NA builds so a bit more intake duration helps especially with a heavy port like that (the build might have been fine for a turbo though....)

Also you didn't say if you degreed the cam and put some advance into it... also did you calculate your static compression ratio, then run the numbers on a dynamic compression ratio calculator? That would help on working out better engine efficiency and making sure the cam was phased correctly... also with that cam, the static ratio in the low 9:1 range would have helped make best power... if you left the block and head without shaving it for a calculated compression it may have fallen flat on it's face due to more duration with less compression but more overlap and scavenging from the headers lowering the useable compression when the intake valve shuts (dynamic compression ratio), which may make it run on bad octane, but leave you with a lot less power than it could make... 16 isn't a bad number for a mid-60's slanted A in stock trim.
Quote:
bronzemaganese guides fitted & turned down to fit Vitoria seals with .650" lift.
I wouldn't turn the guides down any farther than .6... most of the high lift cams max out in the .550 range, the runner flow starts to have diminishing returns after that and unless you are making a blown race only car... it's not worth the $$$ for the extra .05 of lift....
Quote:
It maxed out a big bore gasket.
Unshrouding the valves is great, but if your chamber doesn't line up with the bore properly (core shift), or your overbore doesn't match the shrouding... it's all for naught, the flow will hit the shelf formed by the deck and not help...
Quote:
welding it into a closed chamber kidney shape with quench pads on both sides of the chamber.
There are better things to spend your money on... and if you did say have this done and get the head cryo relieved and milled, before getting here you would have needed to calc out the quench distance between your piston and the shelf... if it's too deep, you get no quench benefits... last time I doodled up a long rod with the proper quench clearance to make it useful, and use the kidney chamber the static CR was about 14.59:1... it went down to mid 13's when I doodled out a slightly less than restrictive shelf... neither would be streetable.
Quote:
By not over porting the port runners & using long runner manifold that will keep a good air speed with plenty of volume on tap.
Here again some compromises need to be made... long runners are not as kind as short runners, and to keep the velocity high you will be looking at loss of flow, and the length of runner determines what rpm the manifold will work best at... I run the hyperpak manifold and it really likes to work well at 3500 rpm+.... that would mean for a guy running a 3.23's an A904 automatic, and a 25.5" tire... you will need to be moving at 80mph to begin to make best use of the manifold...
Quote:
medium effort duration cam ie 216-224 , 108 - 110 cam.
You will have to look and compare the lobe profiles to determine how aggressive the ramps are.... mopar liked long slope high duration cams for performance... a sensible street/strip cam would be in the 220-230 @ 50 range, and would be preferred in the 108 LSA, but if running a long ram may need to have a 110-112 LSA because a large overlap event may cause reversion up the intake runners and cause some issues with efficient fuel flow.

The Static compression ratio for this range of cam depending on if they are say Erson lobes over the Comp Cam Chevy lobe, will want to be in the 10:1 range (and degreed in for best performance... but check the advance against the dynamic CR calculator so you can still use affordable pump gas....)

At one time I thought a short duration high lift cam would have been the ticket, and I had a Comp CCX 256/256/110 .466 lift cam ground... the cam was lazy until 2000 rpm then it started to work... which left a lot to be desired driving around town, light to light....FYI.

Ultimately you may find if you build for a cam in the 250/250/108 .55 lift range, that you will need even more SCR to support it... need taller gears to keep the RPM in the power band...(stall convertor too), and your mileage may end up being closer to the 360 your buddy just put in his A-body...
Quote:
As we get to the upper rpms if we can control the valves without flexing the pushrods
The pushrods will flex anyway... with the bigger cam and the need for stiffer springs the stock style pushrod will flex... I went to custom moly 3/8" heavy wall pushrods starting with my 10:1 build... and now my only worry is the rocker arm snapping if I didn't measure the clearances right or picked a fatigued unit out of the bucket.... I'm lucky that Smith Brothers is just over the mountains from me and so turnaround is pretty quick.
Quote:
Am I on the right track???
I would say you should sit down and think through the requirements for this build:

What is the purpose of the build: Street/Mileage, Street/Strip, Race Only (don't care about how much gas costs...)

Is your car upgraded to handle the build; Safety comes first, building a 12:1 monster and sticking with 9" brake drums will result in very short enjoyment of the car... are you going to try to put a hi-po slant behind a set of 2.76 gears in a 7 1/4" rear end? (Got a spare?)

If you finally get your build and hardware penciled out, we can help you work on what might work best, and make sure you understand that there will be compromises and decisions to get everything to 'jive' and be an enjoyable ride... you can always improve on the next one, once you know what this one can do...

8)
Author:  Killer6 [ Fri Mar 31, 2017 6:41 pm ]
Post subject: 
DI gave it to You straight, and welcome!!
Take some time and use the search function on this site, keyword the
nature of each question & You'll find plenty of guidance & members own
projects w/the very similar line of approach.
There is no doubt the headwork You do will have a large effect on the
outcome of the project. For reference, My old build did 88MPH w/a 2bbl
from a 440B eng., 6 into 1 Mopar header, 276/.490 Purple shaft, in a '72
Swinger with A/C & an 8.75 rear end. I had 1.74 BB exh. valves for int.,
& 1.41 AMC exh. valves. I was conservative w/the intake porting at the
time as I had no flow bench yet, and wasn't sure how much meat was
there to "push it".
Author:  Valiant ute [ Sat Apr 01, 2017 12:40 am ]
Post subject: 
Thanks killer6 & especially duster idiot for having the patience to sort through my ramblings . Obviously taking the time out to help me sort out this jumbled up mess in my head. Building a decent slant seems to be a itch I have to scratch. To me a goal of 250ish hP or 1.1 hp/cid & or pushing a full weight a body into the mid 15's would be great. The only valiant I have is a 1969 vf ute ( dart pick up of sorts ) . It has a 440 / 727 , 8 3/4 / 3.9:1 Detroit locker . Cal tracs & tubbed with springs on the rails. So I have no REAL NEED FOR A SLANT. Except the hate my gear head mates have for them, ( I have 3 groups of racing friends the "gear heads 8-9 second street radial guy's" turbo guys & weird slant guys ) I'm kinda on the fringe of a small group of die hard slant heads but there kinda weird / do stuff strange have weird miths of special slant stuff that only they seem to have. Dickheads to most other racers. But there still ok & generally nice guys. I see so many things holding the slant back I'd kind of like to iron out a few of main set backs so a little slant can break free of its shackles.
Author:  Valiant ute [ Sat Apr 01, 2017 1:04 am ]
Post subject: 
Ok DI as for the vc valiant that I ported the head on . Firstly it belongs to my friend who's in the weird slant circle of friends. He is stuck between my advice & there weird parts swapping of 40-50 year old pieces of junk advice. I was not around for any of the building of the motor. But I can tell you they have know idea of compression or any measurements. But at the time of running 16.0 & 88mph it had .090 off the head & .040 off the block & used feel-pro head gaskets. It was running 16.5 @ 88mph all day & for the last 2 runs he unbolted the exhaust , but kept the exhaust on the car. It dropped down to 16.0 with no change to the mph . That's the only experience I've had with slants but I can see with some basic changes there's power waiting to unleash.
Author:  Valiant ute [ Sat Apr 01, 2017 1:43 am ]
Post subject: 
Since the day of the 16.0 my friend has shaved .020 more off the head & now uses a steel shim gasket , he said they are .020" so that's .110 off the head , .020ish off the gasket & .040 off the block. He has now got Aussie speed big tube headers , insisted I port match his head heaps more in the window to a large intake gasket ( which I advised him not to ). It was around .080 on both sides & on the roof then blended that in & thined the seat cut to about .040 wide. All under his instruction. He installed a 228/232 , .472 / 474 108 lsa cam750 eddlebrock 4bbl & a mad 6al & old junk mopar " truck" electronic dizzy & 205 x 55 14r semi slicks ( nito brand ) oh and arp main studs & rod bolts ( no resizing ) & 2500 stall & shift kit . He had it on a dyno & picked up 26 hp at the wheels over last set up . It runs really strong , pulls really hard , turns the tyres now , but a complete dog off the line at the drags & only at the strip he has the bogging problem. On the street it spins a little bit then takes off & he's really happy but dies at the track. I have not seen the car since all the new parts. I think he needs a new dizzy . Btw he had a 600 eddy on there & he claims it pulls harder with the 750????? He's in Europe on holiday atm so it will be a while before I can talk slants with him again. Once again I see potential but not quite the parts choices I'd make.
Author:  Valiant ute [ Sat Apr 01, 2017 2:24 am ]
Post subject: 
As for my slant build I have 1 test head , a seized heverly rusted truck block with std bore & a long block that's quite clean & turns over nicely & has very little carbon build up on Pistons or cyl head. It's 1000 klms away & I'm working out freight , it will probably cost me $700 ish shipped here. I know not cheap , but I'm not in the USA .
I spoke to the owner of Aussie speed & he said of all his & other racers from all around the worlds testing his hurricane long runner makes the most power on all most every engine tested. He recommended the newer multi north - south , east - west carb flange . Unless all out racing use the 1.5" primary headers. If I use it in my valiant ute with 727 / 8 3/4 . I'll ether need a good 904 & converter or a custom adapter plate & converter for the 727. I know the 727 & my other drive line bits are way heavy & over kill . at least it will hold up & the 727 is 3/4 race box full manual reverse $4k worth built by a well proven race engine builder mopar only. The converter shop guy said with out all the specs, he can't tell me anything . he recommends just run the 4000 big block stall to start with , it will most likely act like a std stall & take it from there. I know I have a lot of planing to do. It could just be a dyno muel or
raced in somebody else's car . Ether way I want to start with practice drilling the oil galleries & oil modding the rusty truck block. And of course developing a good sound performing head . This thread was ment to be about the head , the machine shop didn't call me about the flow bench work today but we have had a major weather event in the last few days & half of our state closed down on Thursday . I'll call them on Monday , I'm dying to know what the std port flowed & my mid effort port flowed. Believe me I have read tons of pages from this site over the years . From what I've read here it seems to me that shrouding , 1.70"/1.44" valves good bowl & short end work , with a little straighter shot at the valves is where I want to put my effort . So that's what I tried . Cheers all.
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