aaronjohn20

alirght you lost me. Could you explain this to me if you would?

TxTtopZ

SCR = static compression ratio, meaning 10.1 9.1 etc. Its what the car should have given the valves are closed (at 0*)with no interference to letting air escape. Dynamic is what you actually get since the intake closes at say 62 abdc

TxTtopZ

Huh? yeah, you got me stumped. I would have figured that combo should be DEEP 12's. Mids at least. Something is holding it up somewhere, just a little. Your right it could be the weight but.....

skinny z

This will explain it.

http://www.empirenet.com/pkelley2/DynamicCR.html

Doom86

I think it's because comp specs "Valve Timing @ 0.006" Lift" and not .005 like everyone else does. The calc was probably set for .005.

Now I need to find a lift because I want to pull the motor and check the bearings and change the oil pump to a M55 with a MrGasket #26 hi pressure relief spring. I'm kinda torn between that and just throwing the heads and cam in on the car and leaving it at that. The parts are just laying around collecting dust ya know?

For the life of me I can't figure it out but I keep wanting to do more work (grinding) on these poor heads. If you have a hint of OCD this may not be the kind of work for you because I keep finding little things I want to "fix".

Maybe I need some new heads to grind on?

TxTtopZ

Nah, you need to just stop grinding those. clean them up, actually POST SOME PICS
Wow, going into builds like these ALWAYS end up way over budget. Be careful is all im saying. cool?
Ok, go to KB pistons web site, they have some good calculators. I would give you a ton of links, but my laptop key board got fried yesterday and im on a back up.

Atilla the Fun

quench is more important than gasket bore when the gasket is only 0.015" thick. If FelPro would make a 0.015" gasket for 305s, then it would be better, except for people wanting to use L31 or TFS heads, who'd still need the 1094s.

TxTtopZ

What about the steel shim .016" head gaskets?
7733Sh1 fel pro

Atilla the Fun

Surprisingly, I honestly was not aware of them. Are they rubber-coated? Got the spec of the gasket bore, or how many CCs they're supposed to be? Or both?

TxTtopZ

I cannot find anything but a part number. A post on hotrodding.com says no on the rubber inserts. Maybe fel pro web site has some more info

Doom86

off of summit;

part number Q7733SH1

Bore (in) 4.100 in.
Bore (mm) 104.140mm
Gasket Material Shim steel
Compressed Thickness (in) 0.015 in.
Lock Wire No

For gasket material is only list steel while 1094's are listed as "Embossed shim with precision rubber coating". Maybe that's why they are half the cost of the 1094's?

skinny z

Still a 4.100" bore however as Atilla has suggested, when the gasket is 15 thou, the crevice volume doesn't add up to much. Quench has more significance.

F-BIRD'88

The heads look great. Don't retard the cam. Use champion RV8C spark plugs.

TxTtopZ

Find out any more info on the steel shim head gaskets?

Atilla the Fun

then spend the extra for the 1094s, the rubber coating makes them easier and foolproof to use.

skinny z

Do those gaskets require retorquing? There's some misleading info out there.

Atilla the Fun

Years ago I got in the habit of re-torquing ALL heads after the first 10 minutes of running. I do them one bolt at a time, following the center-out sequence. Thus I can't say how they would do if not re-torqued.

toolegit86

i am currently doing this same swap but have some questions, my 350 is a 91 piece rear main with 54k on it completle stock rotating assembly, now i installed a lunati bare bones kit (Duration 270/280, Lift .420/.443) just because i heard good things about it, and it came with lifters for 89.99$ from summit, new comp cams timing chain also. now my 416 heads are ported and intake runners/exhaust cleaned up. and they have 194's installed. my question is what kind of head gasket is the best to use?
i am also running a 650dp with modified housing, and a team g high rise.

i was running the swirl port heads but one cracked just a week after installing the motor.

Atilla the Fun

since your 350 short-block is pure stock, that means the pistons are still 0.025" below the decks even at top dead center. Therefore, the FelPro 1094s are ideal.

Doom86

Thanks and good to see you bubs. You helped me a lot reading through archives and with a lot of tips on the first 2 sets that I ported.

My goal with these intakes was to make the port biased taller, which means I didn't touch anything that would increase width anymore then I had to on the common wall and push-rod pinch just working down high spots. Also I didn't touch the ramp from roof to bowl until last to preserve what I can of it.

Most of the time was spent on the roof, valve guides and the bowl/common wall area around the valve guide.

Doom86

That's exactly what I'll do then.

Doom86

Alright I need help clearing up some confusion.

I'm trying to mic the installed height for the springs so I can get the right shims. Attached is a pic of what the problem is. The retainer on the left are the one's that are going to be installed but they don't sit down in the mic like the factory retainers do (the one of the right is factory). Won't this skew the results? To add to the confusion I set the mic to 1.5inches and measured it from top to bottom and it was spot on 1.5 inches.

Also check out the label on these 981 springs in the background. Everything I read says spring rate for them is 370 lbs/in. But the label says otherwise.

I put old positive seals on the intake and exhaust and measured the clearance between the bottom of the retainer and the top of the seal and it's 17/32, or .532. Using one of the springs out of a qjet is great for stuff like this, it has slightly less diameter then the seal and enough pressure to hold the valve closed.

Atilla the Fun

been there, done that. This is when you find yourself needing vernier calipers.

Doom86

Comp cams 981 springs want 1.700 install height, right?

All of the intake install heights with out shimming are between 1.80 and 1.83. The exhaust heights are off the scale on the mic, over 1.9 (looks like 1.94).

Seems like excessive shimming to me. Using one of each shim .015, .030, .060 on the intake should sort them out. But what about the exhaust? Four .060 shims?

Atilla the Fun

981 springs are too stiff for initial run-in with new cam and new lifters. The 980s are far bettter.
With 416 heads, you have to use the exhaust rotators with non-rotator springs. It's better than a stack of shims. Just wash a bunch of rotators in mineral spirits, let them dry, leave them in motor oil over night, then in the morning find the 8 that feel like they have the smoothest operation.

Doom86

I've never heard that 981's are too stiff for break-in's before. From what I've learned it's only a problem with dual springs. I do have the springs that came on these heads but that sounds like a real PITA if there's a way around it.

Rotators huh? But they are so ugly and will they like seeing +6000rpm in 1st?

What about the oil shields do I need them?

With the stock garbage on the spring mic the installed height is 1.76 in, 1.77 ex. Should I just use this crap with the 981 spring and put in a .060 shim and be done with it?

Open to any suggestions. Like I said before I'm trying to squeeze all the power I can out of this.

Atilla the Fun

If you use COMP's assembly lube aND COMP's break-in oil, you might have a successful break-in with 981s, but if you kill a lifter or wipe a lobe, I won't be surprised.
Anyway, The oil shields go in the trash. You want the oil to cool the springs, it'll extend the life of the springs. Hotter-running springs fatigue quicker.
Since your 6000 rpm blasts are only at the top of first and second, the rotators should live. If it was endurance racing or marine, with sustained high rpm, then I'd skip the rotators.
If you're more comfortable with a big stack of shims, go ahead.

Doom86

Alright boys I know I said that I was done with porting these heads but I spent a good hour last night going over them with my fingers and marking high spots with a sharpie. Also I wanted to change the bowls a bit so I used the marker to plot out the bowl.

This led to a 6 hour porting session today. Most time spent in the bowls and the roof was again raised and the push rod pinch area opened up a bit. They were finished with 40grit rolls lightly so they're still rough in some spots.

I am so very done with these.

Some pictures that actually turned out. I took 30-40 pictures but the lighting is terrible. There's still loads of dust from polishing in them so don't mind that.

TxTtopZ

These are your first attempt to port heads correct? They look pretty good! Depending on your results is weather I attempt the same ordeal... Why not give the combustion chambers a polish? I would do it, it helps reflect heat back into the chamber and prevents detonation by not having any hot spots. Next I would use some high flow valves or back cut those.

Atilla the Fun

That much port volume with such tight short turns and 1.94" valves isn't gonna give good port velocity even at higher rpm. Consider 2.02-ing these and using them on a 355.
The best way to get all the dust out quick is WD-40.

TxTtopZ

You can tell that with an image off the net? I would have figured that to be more of a measured volume outcome. I guess if you have seen enough then... What if he were to use some high flow race valves to keep momentum going as much as possible? Granted velocity would be achieved quicker, but it may not be that high if your right.

Doom86

Nope these are the 3rd full set I've done. First set (416) broke through trying to clean up a rut that the pneumatic grinder dug on the wrong side of the bowl and a rocker stud cracked while pulling them. Second set (083) turned into swiss cheese at the push-rod pinch and broke through in the bowl from a chattering carbide and the cast being too thin. You can find pics of them by searching I documented them as well.

I was planning to use the 1.84in 1.5ex that came in them since the heads were in such good condition and I'm "not so" rich at the moment. The valves were radius margin and back by me using a drill, grinder, and keen eye.

I did remove a bit of metal on the last session I think I need to CC them again.

Atilla putting 2.02in 1.6ex is not out of the question but it may set things back a few months and summer will be over. Unless someone around me wants to trade machine work for port work?

TxTtopZ

I wish I could find those threads so I know what to watch out for. Do you happen to remember the thread titles?

Doom86

Here you go I dug up a pic from the thread to show you where it's thin. I went WAY too far on this side anyway. It's the exhaust side of the intake bowl.

TxTtopZ

makes me wonder how thin the casting is in other places.... thanks for this pic! Anyone else have any thing like this? We can all learn more from these kind of pics for sure.

Doom86

I don't have any pics of any other holes because they are thick in all the right places. There is a amazing amount of metal in the common wall bowl area up by the roof. The same is true for the roof its self.

Look at a picture of a cross sectioned SBC head. The intake bowl on the exhaust side is thin and it's like that almost in it's entirety until past the valve guide.

The old head that I went through on is still sitting around I was thinking of using it to see just how much of the roof can be removed.

TxTtopZ

May as well! I have been looking up some other boards flow numbers with the 416 heads and 3.750" bore fixture...not too shabby. F Bird 88 has some nice numbers too...

Atilla the Fun

Vortec intake port short turns are just over 3/16" thick, but I never found any gains there, even with huge valves.
I had a cracked 062, so I attacked it just to see how thick the iron was at that point.

NAASBC355

The pushrod wall in the port entry can be ported an inch wide in the mouth of the port, and thats it withought epoxy, and your lucky to get it that far. Use your t gauges. This is of coarse if you have a set of heads that have been ported everywhere else first. Porting in the port entry should be the last ditch effort to gain airflow. Very little gain can be seen porting there below .400 lift. with 1.94, and below .350 with a 2.02 valve. Less is more: porting heads should be about air flow vs. port volume. It's called port velocity. You arrent trying to re engineer the whole cylinder head just clean up whats already there. Air doesn't like to turn or make sudden changes in direction, and the farther from the valve you get the less anything you do matters. Concentrate your efforts within a half inch either direction from the valve seat to see real gains in the flow curve. Remember less is better. you will be supprised how much gain can come from so little effort if you cut in the right places. Lastly more port jobs that I've seen have been ruined, by a crappy valve job more than anything else. When it's a performance application you must demand a quality valve job. I use a killer set up that really brings airflow through the port. If your machine shop can't say the same then you need to find someone else.

~Couch

Atilla the Fun

The first secret of the perfect valve job is that air will flow over a 15 degree (or shallower) angle the same as if it was a perfect radius. That's why we use increments of 15. If the seat is 45, then the adjacent angles will be 30 and 60. Then follow that up with a 75-degree bowl hog. The hogger should be adjusted to cut as deep into the bowl as possible without hitting the valve guide, when the other end of the hogger has narrowed the 60 degree cut to about 0.055".
Then there's the de-shrouding sweeper cut. This will remove material from the walls of the combustion chamber. Ideally, the best way to set it is to put the bare heads, cleaned, on the bare block, at the final bore size (already honed) and use a new red sharpie to mark the heads.
Then set the cutter to just barely remove the red ink. This cutter should end in a 15-degree angle, and the idea is to not cut any deeper than necessary to narrow the 30 degree angle to no less than 0.045".
This isn't best for everything, but it is so dang close that it will do excellent for all production SBC heads, including the mighty Vortec L31 heads.
Why anyone keeps this a secret is beyond me.
Print the above, take it to your local machine shops. Have them read it. If one argues, don't trust that one to do your heads.
You won't get significantly better results from anything else.

NAASBC355

I have heard of machine shops and have freinds in the industry that use a 15 degree top cut. Don't ask me why. I don't use the specific angles Atilla mentioned, but again it's close enough for street stuff. I disagree with the not getting significantly better results from something else. I have a set up that is proven on the flow bench killer with factory heads especially, but for street stuff, I agree just a good clean 30, 45, 60, with some kind of blending bowl cut, and a chamber cut. Back cut the valve, and you've done more improvements then you would anywhere else.

one last addition um air flows over a perfect radius like it would a radius thats why I use a radius cutter profile on my exhaust seats among other things. The intake needs sharp distinct angles on the seat so it can sheer the incoming fuel

~Couch

Doom86

I just finished checking the intake runner volume again and it looks good. (re-posting other volumes as well)

Chambers: 57cc
Intake: 171.5 cc
Exhaust: 63 cc

That seems to be about the perfect size for a healthy 305. If I put these on a 350 at some point I may work them some more. Which would probably be more roof work and push rod pinch.

Couch the "less is more" way of porting makes complete sense to me too, I was talking about that my self earlier in the thread. It only makes sense if you achieve like flow with less volume that the lesser volume has higher velocity swirl.

Atilla the Fun

Couch is correct that a sharp edge in the intakes can help get fuel back into the air, but only if there is a problem with this in the first place. The 15 degree angle is NOT enough to do this.
The guys who claim a 15 degree top cut aren't going directly from 15 to 45 with no 30 in between. If you do the 5 angles you should for best flow; i.e. 15/30/45/60/75, then the 15 becomes the top cut by default. If only the standard 30/45/60 angles are used, then the 30 is the top cut by default.

Atilla the Fun

The thing that concerns me is that you got the volume be increasing the cross sectional in places where we don't want to increase the cross-sectional area. We do want the air to slow down as it gets to the bowls, so the air will make the turn. But the pushrod pinch isn't a restriction for what the best 1.94" valves can flow, so you really shouldn't've done ANY grinding there. Since you did, you've hurt the velocity that 305s need more than 350s.
Honestly, if you could do a back-to-back comparison between your 416s and mine or Couch's, in identical cars with identical 305s, you would be surprised at how different they would both feel to you, and behave in various driving situations.
Please, big-valve those and slap them on a 355. In the meantime, please get another set, for around $75/pr, around here, and try them the way Couch and I have advised.
Remember, I'm here to help people get the best possible results from what they have, not to condemn or humiliate anyone.

TxTtopZ

Hey Atilla, isnt filling in the heat riser worth about 10hp? I dont think anyone has mentioned that yet... I know its worth some CFM..you can use some hard block block filler. And another trick is using epoxy around the pushrod pinch... why does that help flow.....now that were on the subject?

NAASBC355

No they are going 15 to 45 with no 30 thats what I was saying. We don't use 30 we figured out a much better flowing top angle, but the Chebby chamber itself is already flat flat why would you want to flatten it more... beyond me. Doing that makes the air see more of the chamber wall than it already did before which is really bad for flow.

A 5 angle valve job refers to the 3 on the seat and the two on the valve. When you add the 6th it's the bowl cut, and i don't think the chamber cut counts as it should be a radius cut.

The 15 degree difference is enough to stir things up. We deal with people at Del West, and Weld Tech about this stuff all the time in their wet flow benches they test different approches to this issue all the time. The 15 degree angle doesn't flow air as well as a radius cut, but it greatly enhances what the fuel does. We didn't really know that until recent years where technology could show us what we were accidently doing all these years. Trully though it's not enough to atomize ALL of it just helps atomize a very small percentage that would otherwise be left out. Every little bit helps, but you're right you can't soley rely on this you are correct.

~Couch

NAASBC355

1. Yes filling them is good for SOME power, but not because of flow in this case. I've never used block filler in anything that high temp, I don't think thats what you should use. You can buy cast iron plugs from edelbrock and there is also some real high temp epoxy for exhaust it comes in a tub that stuff works pretty good. If you buy vortec heads, or aftermarket it's eliminated.

2. Because you port out into the epoxy making a larger port entry cross section. When you are done porting there is no iron left. That was the way you used to have to make high volume runners with factory heads. You just buy your heads that way now days.

~Couch

Doom86

No insult taken thanks for the information.

Granted I did work the push rod pinch the shape wasn't destroyed and that's what creates the venturi effect, right? There was plenty left, enough was left to keep the rocker voids shrouded. I worked that, the roof and the bowls to get the 1.75cc difference from last CCing so bias between height and width should roughly be the same. This port is very tall I have been over and over the roof.

Port height has always been my concern and anyone who reads through this long winded thread can see that I hope. I'm not sure where you guys are getting the idea I'm hogging these out because when I do research I can't find one report of someone porting these and getting under 177-178cc. Because they "remove metal everywhere the carbide can reach".

You know there's another motor "out there" with a very like bore/stroke ratio of the 305 and it really loves tall ports. Maybe the 305 will too?

Atilla the Fun

First, the shape and venturi effect don't mean jack for a street 305 with modest valves. Velocity isn't everything, as swirl-ports prove, but it is important. I'm not saying you're horrific amounts, but it enough to feel. And to show up on your timeslips at the dragstrip. 305s are already bad enough at that.
And just because everyone else measured 177+ cc doesn't mean they couldn't have gotten the same flow numbers at 168 cc. Again, there are lots of places the carbide can reach that are NOT hurting anything.
Go ahead and try it, just for the educational value of it. But then do a pair my way, and be amazed. Try yours and mine on your 305, then try both on a 355. Education is worth such a modest investment.

Atilla the Fun

Admittedly I no longer have access to the SuperFlow 1020, because of my cancer, but I do have all the notes I wrote down when I was using it.
I never found better flow by using angles greater than 15, testing both 882 heads and Edelbrock Victor heads. I also tried using angles of 15/25/35/45/55/65/75 and it wasn't enough better to be worth the extra cost. Not on the 882s, and not on the Victors.
Atomization ridges are great for Holley carbs in cold weather. But with port injection, forget it.
As far as what I typed about the sweeper cut, it seems you misunderstood me.
Moving on, a 3 angle valve job is 30/45/60. A 5 angle is 15/30/45/60/75. Facing the valves isn't counted, and neither is the back cut if applicable. Some valves don't have enough material for adequate seat width and any back cut. This is lighter, which is why they're offered that way. But that's for professional racing, not street/strip. None of us ever see the high side of 7000, so better to have heavier valves with better flow.