Cylinder Head Porting and Power Production

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One thing...the more you lift the valve, the more you use of the port...so the port needs to be better and better the more you lift the valve (and rpm). If you look at some heads, they work really well with shorter lifts....others work much better with a bunch of lift. Just my thoughts....
 
yellow rose said:
Flow isn’t always good. I think everyone can agree on that. It’s where the flow is and when it is that matters.

What goes on at TDC is far less important than what happens later, especially when dealing with reversion.
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It took me a awhile to realize easy flow goes both ways... and that’s not always best.
 
RAMM said:
You are not wrong and your ability to read between the lines is impressive. I do have the TF's in mind because I have never worked with them and I have never worked with W5's either--only pressure tested one once. Like I said the jury is out on the TF's for me as I have only seen one build that I feel did those heads justice and it was built by a pro (Mike @B3RE ). Anything else I have seen online kinda leaves me wanting for more. As soon as they are back in stock @ Motorstate I plan to order some to experiment with. Best looking SBM chamber I have seen yet. J.Rob
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Thanks for the compliment Jesse, although I'm certain you would have similar results. A quality engine builder is worth their weight in gold.
 
RAMM said:
I know that a head flowing 240 cfm @ .400" is probably going to work very very well for most purposes. I also know that a head flowing 230 cfm @ .400" is also going to work very very well also. What I'm trying to say is the flow rate really doesn't tell even half the story as far as I can tell. This is why the jury is still out on certain heads until they gain a reputation for just "working" . I have the EQ Magnum and Chevy Vortec in mind here--these heads --never mind the dyno results--just flat out work. So defining what "works" means is problematic as well. This is one reason why these types of discussions get convoluted so quickly and easily. J.Rob
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I haven't read through the whole thread yet, just up to this post @RAMM ,
Doesn't what you have said indicate that there is an unmeasured aspect to the relationship between port velocity and port volume, or perhaps the intake manifold volume&flow, and or carb, and exhaust flow as well. Looking at the engineering of the cross ram induction, and reading the books that cover exhaust design, indicates to this student of students that there is a big picture factor of the whole system (kinda like what you guys and the hotrodding books say the sum of the upgrades can supersede the measurement of each individual upgrade.

I dunno if this sounds stupid or convoluted, but maybe exhaust volume-in direct relation to engine volume/size AND RPM contributes to exceptional flow throughout the whole system. The Exhaust books claim this, some even have charts with rough figures, but nothing listing exact volumes in relation to engine sizes + RPM + etc. -like a scavenging suction inverse equivalent to forced induction or the cross ram induction's effectiveness
 
@greymouser7 Hey bud!

Well written my friend and I’ll just say yes. Keep studying up. The books won’t give exact figures due to the various combinations that could be built. Your on track. A good way to see the effects of the various parts of the engine work well or not can be found on you tube by people running an engine on a Dyno and making changes so you can see what happens.

Here’s a tip, search the name Richard Holdner on you tube.
 
I appreciated this threat. There was some really interesting information and ideas dispersed in it.

Some assumptions I am making based on this thread and other things i've seen.

All other things being equal is the head that makes the most flow at the lowest intake cc runner going to be the best hed because it will have higher velocity/better mixture quality and less falling out of suspension? Also I assume the higher velocity helps pull harder though the overlap cycle?

Also a carburetor if someone puts a really big carb with really large intake bores,venturi vs what the engine is after this would really slow down the velocity and you would have more falling out of suspension and a poorer mixture quality?
 
Ivoryk3ys78 said:
I appreciated this threat. There was some really interesting information and ideas dispersed in it.

Some assumptions I am making based on this thread and other things i've seen.

All other things being equal is the head that makes the most flow at the lowest intake cc runner going to be the best hed because it will have higher velocity/better mixture quality and less falling out of suspension? Also I assume the higher velocity helps pull harder though the overlap cycle?

Also a carburetor if someone puts a really big carb with really large intake bores,venturi vs what the engine is after this would really slow down the velocity and you would have more falling out of suspension and a poorer mixture quality?
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never seen a bigger carb not pick up on a small block Mopar.
I am sure even an ultra healthy 318 shifted at 6200 doesnt call for a 950hp, but it was a 1/10 faster than a 750 was on the same extremely well sorted out motor.
Have no idea about this or that falling out. Just know, at the track, bigger has always ran quicker for me.
 
That surprises me. Very interesting

Thank you


B3422w5 said:
never seen a bigger carb not pick up on a small block Mopar.
I am sure even an ultra healthy 318 shifted at 6200 doesnt call for a 950hp, but it was a 1/10 faster than a 750 was on the same extremely well sorted out motor.
Have no idea about this or that falling out. Just know, at the track, bigger has always ran quicker for me.
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Ah, the bigger carb. Nick's garage [ Canada ] you tube. Ran a 454 CHEV, mild rebuild, made over 500hp with 750 Holley. RPM was over 6000. Airflow indicated 770 cfm, soooo Nick installed a 950 Holley. Engine lost 10 hp at peak & 10ft/lbs everywhere.
 
Bewy said:
Ah, the bigger carb. Nick's garage [ Canada ] you tube. Ran a 454 CHEV, mild rebuild, made over 500hp with 750 Holley. RPM was over 6000. Airflow indicated 770 cfm, soooo Nick installed a 950 Holley. Engine lost 10 hp at peak & 10ft/lbs everywhere.
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I knew that would happen as I've done the same thing, many many times. When the engine is moving near or slightly more than rated carb capacity, it rarely picks up when you move to a bigger carb. If it does pick up a bunch than usually something is wrong with the smaller carb. You could see the valvetrain issues in the air that engine moved. Another reason I like the air turbine. J.Rob
 
RAMM said:
What 950 are we talking about? The Proform style or Holley? Did you happen to flow the 950? J.Rob
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950 Hp
It was on the enginemasters 318 i had in a 71 Duster that made 477 horse. Pretty well known motor, magazine articles, etc
Carb Guru Randy Malik set it up for that motor.
I had it on my 10 to 1 360 as well.
Had a 416 eddie stroker some years ago
750, 950, 1000, 1025 race demon, 1100 pro systems dominator
1000dominator fastest, 1025 might close, best manners others good bit slower

for the record, several years ago when i had that 318 was discussion on Moparts if a smaller carb on my 360 might pick it up.
Brett Miller said smaller carb will slow it down, bigger, faster
 
Bewy said:
Ah, the bigger carb. Nick's garage [ Canada ] you tube. Ran a 454 CHEV, mild rebuild, made over 500hp with 750 Holley. RPM was over 6000. Airflow indicated 770 cfm, soooo Nick installed a 950 Holley. Engine lost 10 hp at peak & 10ft/lbs everywhere.
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did it run at the track?
 
B3422w5 said:
did it run at the track?
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Of course not, this was his latest video--Napierville is closed right now. Engine wasn't exactly a mild rebuild with some very nice AFR heads and I think best pull was near 580HP/580tq. Even more curious now that I think about it is the requirement for a bigger carb when using a dual plane manifold--which this BBC was. I know what I've seen and it lines up as far as what the dyno shows us. J.Rob
 
B3422w5 said:
950 Hp
It was on the enginemasters 318 i had in a 71 Duster that made 477 horse. Pretty well known motor, magazine articles, etc
Carb Guru Randy Malik set it up for that motor.
I had it on my 10 to 1 360 as well.
Had a 416 eddie stroker some years ago
750, 950, 1000, 1025 race demon, 1100 pro systems dominator
1000dominator fastest, 1025 might close, best manners others good bit slower

for the record, several years ago when i had that 318 was discussion on Moparts if a smaller carb on my 360 might pick it up.
Brett Miller said smaller carb will slow it down, bigger, faster
Click to expand...

I know the engine and also what it made in 2010, and yes Randy is the real deal when it comes to Holleys. I believe he worked for Holley . Randy also did his thing to the Magnum RT heads on that engine which I'm sure was skillful.

In every instance did all three metrics improve with the larger carbs? As in best 60ft/ET/MPH?

Is it possible that on a underheaded large cube stout engine that the larger carbs slowed down the overall intake tract airspeed? Mixture quality aside. Also to move to a 4500 you had to have used an adapter of some kind--was something similar used on the 4150's? Just curious. J.Rob
 
RAMM said:
I know the engine and also what it made in 2010, and yes Randy is the real deal when it comes to Holleys. I believe he worked for Holley . Randy also did his thing to the Magnum RT heads on that engine which I'm sure was skillful.

In every instance did all three metrics improve with the larger carbs? As in best 60ft/ET/MPH?

Is it possible that on a underheaded large cube stout engine that the larger carbs slowed down the overall intake tract airspeed? Mixture quality aside. Also to move to a 4500 you had to have used an adapter of some kind--was something similar used on the 4150's? Just curious. J.Rob
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Randy didnt do anything to the heads. They went mid 270’s @600 lift. They pretty much just bolted them on after a valve job.
Yes, i used the moroso adapter on Patricks dominator.
 
B3422w5 said:
Randy didnt do anything to the heads. They went mid 270’s @600 lift. They pretty much just bolted them on after a valve job.
Yes, i used the moroso adapter on Patricks dominator.
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Yes I know they were purchased ported, I'm also sure Randy optimized the valvejob.
Did all three drag metrics improve? J.Rob
 
RAMM said:
Yes I know they were purchased ported, I'm also sure Randy optimized the valvejob.
Did all three drag metrics improve? J.Rob
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Dominator didnt 60 foot as good as the race Demon, but was better elsewhere.
In fairness to the dominator, i had a Hemi Dart hood on that car, and with the adapter and carb, it didn't have as much clearance as i would have preferred.
I sold the race Demon 1025rs after the Dominator worked out, dumbest thing i ever did. It was a really sweet carb. Nicest 4150 i have ever had.
All these swaps were done on a flat tappet 416 with W5’s. I ended up breaking it( Eagle cast crank)
 
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RAMM said:
What were the changes in MPH? J.Rob
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Its been a while, but i think the Dominator finally got it over 129, think it had been a little over 128 with the 1025
I then swapped in a 112 cam, didn't like that at all, wouldn't leave off the foot with the Dominator. Was a slug. Never again. Scott Brown talked me into it.
Patrick and i used to work together before he opened his carb shop.
He loaned me a few carbs to try 750/1000, ended up buying the Dominator.
 
B3422w5 said:
Dominator didnt 60 foot as good as the race Demon, but was better elsewhere.
In fairness to the dominator, i had a Hemi Dart hood on that car, and with the adapter and carb, it didn't have as much clearance as i would have preferred.
I sold the race Demon 1025rs after the Dominator worked out, dumbest thing i ever did. It was a really sweet carb. Nicest 4150 i have ever had.
All these swaps were done on a flat tappet 416 with W5’s. I ended up breaking it( Eagle cast crank)
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Just curious
Did the engine survive the crank failure?
 
RAMM said:
Is it possible that on a underheaded large cube stout engine that the larger carbs slowed down the overall intake tract airspeed?
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Yes but the smaller port places more vacuum on the mixture improving its vaporization rate which improves the mixture at burn time.
B3422w5 said:
Its been a while, but i think the Dominator finally got it over 129, think it had been a little over 128 with the 1025
I then swapped in a 112 cam, didn't like that at all, wouldn't leave off the foot with the Dominator. Was a slug. Never again. Scott Brown talked me into it.
Patrick and i used to work together before he opened his carb shop.
He loaned me a few carbs to try 750/1000, ended up buying the Dominator.
Click to expand...

Were they all Annular booster carbs? Did you retune each time or was it just a straight swap. Did you find best timing for each carb?
 
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