SBM Edelbrock/Speedmaster Head Data

[273]

Then why do you get behind it so much and defend it so hard?
You swore up and down and fought really hard for what…. Years that an engine that calculates to consume 600 cfm should only use that since a larger carb won’t produce any meaningful amount of extra HP but only give a worse throttle response, lower mileage and a crappier pedal feel on the road?

Never once have I ever argued that position, I've said over and over the carb formula is junk as a carb formula, It tells the approximate displacement of a running engine that's it.

Dozens here argued against you but you stood proud until engine masters showed you wrong.

The applied science is in the program. What’s to argue about there! LOL!

So the formula over valves carbs?

People over value what that formula predicts is needed when choosing a carb.

Eg. A 360 @ 5500 rpm that formula says 450-500 cfm is the ideal carb I definitely don't agree with that outcome, never have/would.

Is 1.5hg the optimal goal point? For you personally that is.

Nope, it just what basically the formula results would be.


I think your thinking of Hysteric he's the small carb/head guy

 

[rumblefish360]

Never once have I ever argued that position, I've said over and over the carb formula is junk as a carb formula, It tells the approximate displacement of a running engine that's it.

Yeaaaaa - Uh Huhhhhhhh

People over value what that formula predicts is needed when choosing a carb.

I find 99% laugh at it.

 

[Earlie A]

I always say one port is easy, but the work starts porting the other 7 to match. That my simple way of saying it. My buddy won’t even port a head without it being cnc’d first. Who’s the smart one him or me. Lol. He’s done porting work longer than me and went to Joe Mondello’s hands one class. When I told him Joe died I think he felt like crying. He had questions he put off asking him. I’ve usually pick up 10-20 on most cnc’d heads I’ve touched minimum. Just remember a cnc program can’t get every port the same (case in point my TrickFlow heads) so you average out a great port with a good port as that’s what the engine does.

Eight ports! Forget that. Us R&D types wear pocket protectors, use calculators and work on 1 port at a time.

 

[Earlie A]

Here's the latest tests. Still curious about the 35 deg top angle so that's what I'm working on.

Test 350 is with a new 90/75/60/45/30/15 valve job and Ferrea 30/45 valve.

Test 351 is sinking the intake valve (not the exhaust) around 0.080" and recutting the valve job at 75/60/45/35. A 4mm radius was cut at the top of the 35 deg angle where the 35 meets the shrouded side of the chamber. Same valve.

Test 352 is extending the 35 degree top cut as far as possible with clay. Again, this covers up the spark plug and extends the 35 degree angle more than actually practical - but this is a test. Things can be modified later. Same valve.

Initially, this looks like a bad move for low lift flow, but there are a few things to consider. First, since the exhaust valve has not been sunk, it is very much in the way of intake flow. Also, I think there is a good bit of shrouding in the spark plug area that needs to be addressed.

The flow past 0.25d has increased dramatically. May not be usable for the street or translate to horsepower, but all of this is usable for education.

 

[rumblefish360]

IMO, you need to put the spark plug in and adjust the clay around the plug.

 

[Earlie A]

IMO, you need to put the spark plug in and adjust the clay around the plug.

Yep. It will be there eventually.

 

[Earlie A]

When you 1st posted it I tried for a few minutes to figure where 0.0009875 comes from, part of of it must convert cubic inch to cubic feet, per revolution (every other stroke) 1 cubic in = .0005787 cubic feet / 2, so 360 x 6000 x .0005787/ 8 /2 = 78 actual cfm vs the 266 cfm of need head flow. That's far as I got, problem with head flow is the depends on a depression, there's not a direct translation between the two. Why the carb formula doesn't work unless the goal is to have 1.5 hg at WOT.

Finally found an explanation for the 0.0009875 number.

 

[rumblefish360]

What book?

 

[Earlie A]

What book?

Practical Engine Airflow, John Baechtel

 

[273]

Good find, should of known it's based from Pipemax.

 

[273]

Problem with formulas like that not saying it wrong but more for building a certain type of engine, an average guy that puts together a 360 or 408 with compression and around a 235-245 cam only got a few head choices basically stock, speedmaster/edlebrock or trick flow, so around 400 hp or 450 hp or 500+hp.

 

[273]

Here's another guy's channel you might want to check out, I just finished watching his latest video, Dyno Test: Compression vs Flow

 

[rumblefish360]

A bunch of that video was covered by @IQ52. Jim showed a few results from his dyno tests. More information is always good.

 

[Newbomb Turk]

Here's another guy's channel you might want to check out, I just finished watching his latest video, Dyno Test: Compression vs Flow

I watched that. I need to watch it again. What he credits to compression increase I say is something else. He’s just missing it because he is stuck in a rut with his testing methods.

 

[273]

I watched that. I need to watch it again. What he credits to compression increase I say is something else. He’s just missing it because he is stuck in a rut with his testing methods.

What was he over looking?

 

[Newbomb Turk]

What was he over looking?

He believes his flow bench when it’s lying to him.

 

[polyjohn]

Any updates Earlie-A?

Wonderful S&M info here indeed.
Gonna get me a set and hope to get 400hp with my 360.

Best wishes from PolyJohn UK.
RIP Pittsburgh-racer, a sad loss to us all.

 

[Earlie A]

Any updates Earlie-A?

Wonderful S&M info here indeed.
Gonna get me a set and hope to get 400hp with my 360.

Best wishes from PolyJohn UK.
RIP Pittsburgh-racer, a sad loss to us all.

Hello PolyJohn,

I have actually been testing quite a lot lately. Usually 2-3 hours before work each morning. Most of my tests have been with the Speedmaster head and a 2.02 valve. For months I’ve been trying to make a 300 cfm port that does not nose over/back up at 0.500-0.600 lift. I finally hit a legitimate 300 yesterday with only a slight dip in the curve at 0.600 lift.

It sure would be nice to have PBR around to get some direction. I’m thankful for the posts that he left us. It’s amazing how many times I’ll learn something and then remember one of his posts, especially regarding the short turn. I go back to them frequently. He is missed for sure.

As far as your build goes, 400 hp from the 360 should be well within reach. If you go with the Speedmaster heads, get them bare and have a good valve job done, maybe even go to a 2.055 valve. I think SM makes the throat too large to begin with. On the bench this head likes an 88-89% throat. I think that would work better on the street than the 91-93% throat they come with.

On another note, I’ve got some 318 poly heads I’m excited about grinding on. I just wish there was more metal around the port. You’re a poly guy, right?

 

[polyjohn]

Hello PolyJohn,

I have actually been testing quite a lot lately. Usually 2-3 hours before work each morning. Most of my tests have been with the Speedmaster head and a 2.02 valve. For months I’ve been trying to make a 300 cfm port that does not nose over/back up at 0.500-0.600 lift. I finally hit a legitimate 300 yesterday with only a slight dip in the curve at 0.600 lift.

It sure would be nice to have PBR around to get some direction. I’m thankful for the posts that he left us. It’s amazing how many times I’ll learn something and then remember one of his posts, especially regarding the short turn. I go back to them frequently. He is missed for sure.

As far as your build goes, 400 hp from the 360 should be well within reach. If you go with the Speedmaster heads, get them bare and have a good valve job done, maybe even go to a 2.055 valve. I think SM makes the throat too large to begin with. On the bench this head likes an 88-89% throat. I think that would work better on the street than the 91-93% throat they come with.

On another note, I’ve got some 318 poly heads I’m excited about grinding on. I just wish there was more metal around the port. You’re a poly guy, right?

Many thanks for your reply Earlie-A,

Yep, Poly and big-blocks for me, but things are changing.
We are blessed with an abundance of 383's and 440's in the UK.

Raced my Dart with an all iron 440 back in the 90's and the pocket-money ran out.
So I would like to return to the 1320 with a trick Duster and a small-block.

Bought some S/B Edelbrocks a while back and never used them so 'got rid'.
Like the look of the SM heads and got a pair coming next month from Rialto.

400hp is a starting point, but the iron 440ci made 550hp and ran 10.40.
Was going to hot up the 402ci (Pavlovich) Poly but that's in my street car at present.

I liked the ovalport Hinkles Poly 426 heads, but funds are limited for a UK pensioner DOH!
Head porting is a brilliant way to 'lose yourself' like in an altered state when grinding/polishing...

 

[polyjohn]

Always had a fascination for Ovalport heads myself.
Mother Mopar did try them in and around 1970 with an Ovalport 440 pass. car head.

Got a pair here in England that were done by Weslake Engineering, also in Kent.
Reportedly capable of 600hp for NASACAR after the Hemi ban in 1971.

D-port exhausts and 2'' inch tall intake runners.
Ran them on a street engine back in the 80's they was wicked.

The Big-block porting plate is overlaid on a W2 gasket to show the difference in size.
It was stamped 'W2' but I think they are really 'W1' heads.

 

[polyjohn]

Nascar type STR tunnetram intake for the W1 heads.
Next to an MI intake to show the size.

 

[polyjohn]

Just modifying some 2.02 x 1.60 Poly heads for a Schneider 0.525 camshaft they did for us.

That is the largest Poly camshaft we can grind with current blanks available.
Crane dual valve springs is the only ones that would fit and take 0.550 lift.

The Hinkles got Compcams to do a Rollercam for them, trick Poly stuff indeed.

 

[abdywgn]

Thanks for sharing history and innovations with us. Found the Poly fascinating when I first learned about them. Only took about 50 years to acquire one, not because they couldn't be found, but was playing with 340's and a 360. Have you run in water with the 2.02 valve? The LS intake swap looks interesting...just need those angled adapter plates. Thanks for sharing the pictures and info!