Is there a big gain to milling down the center divider 1" on a Performer manifold,to be used on a 455 making about 450hp and using a 750 Holley.This car is 99.9% street.Or could it hurt performance in this case...

 

Milling the center divider allows one side of the carb to "see" the other side a little. This gives the engine some of the effect of having a single plane intake where any cylinder can pull from the whole carb, not just half, but not to the degree of a single plane. It helps some on the top end without lowering intake velocities as much on the lower end. In your application, though, I don't think it will make a real difference seeing how you won't be seeing a lot of time above 4000 rpm with a mainly street driven car. You have a carb big enough to let your engine breathe plenty at street rpm's. Leaving the dual plane as is will give you the most torque, anyway.

 

Milling the divider will make more peak HP with a 750 carb, if you can fit a 1 inch open spacer it will also accomplish the same goal, more peak HP, a 4 hole 1 inch spacer will probably make more average HP, and TQ.

 

Thanks You guys....stock hood on a 69 442,might have clearance problems or I would have tried the spacer,so I thought about milling the divider,it's a pretty neat little trick...and sounds like it works...mostly street but will be making a pass or two at the local track and shifting at about 5400 or so....

 

If you want to try it, give it a go. You have plenty of torque with the 455 and worst case scenario, you buy another manifold if you don't like the change.

 

Check out my dyno session on a mild 455.
Your carb is too small for 450hp. You need to cut down the center divider at least 3/4" and bullnose it.
You won't lose a bit of low end and you'll pick up power from 3500-4000 up.
You still need a bigger carb.

 

No it won't. With the spacer you're actually adding more plenum area, moreso than just cutting down the divider.

Check out my dyno session with the RPM intake. It had the divider cut down but still picked up 14hp just by adding the spacer.

I wish more people could back their statements with facts. I realize not everyone has access to a dyno, but if you would have thought for a minute I'm sure you would have realized your statement was incorrect.

 

Always appreciate all the input fellows...Mark I read your post,and like most realize this guy knows his stuff.I used an online calculator and for what it's worth,put in my specs to see if my carb was OK for the street. It came up with,I need at least 744 cfm's for street use,and at least 830 cfm's for strip,,,,not a dyno but all I have,with the exception of reading the results you builders with dyno's post for us all to take advantage of,,,I for one appreciate it when you take the time to do that..

 

Ihengineer76...Was thinking the same ,but I think it will work,and was thinking about trying to bump my hp anyway,more intake manifold and more carb...well maybe next year.

 

Let us know how it turns out! One of the most fun parts of being a car enthusiast is being able to experiment with mods and see how they effect your car.

 

I did check out your dyno tests, all those tests tell me is this: Massive valve float, which got worse and worse. Back my statements with facts, look for a spacer test next week. As far as access to a dyno, well I tested 3 engines this week alone, you might be surprised at the amount of dyno testing Ive done. I included a dyno test from one of my typical 9.1 comp 467s, with a 228 @ .050 hyd flattappet, stamped LS6 rockers, 236 peanut port production heads, dual plane with divider, 4 hole 1 inch spacer, a nice comparisome to your 455 intake test engine. Infact my advice to you would be to watch and learn. Lesson 1. 325 open and 135 on the seat does not control a hyd roller. The only reason I can think of using that type of spring pressure is if your selling these guys cast cam cores, which you should know is a no-no, ( after looking at panos build by Cutlassefi, a billet cam core was used, dont want to mislead anyone) a billet core with 160/380 would probably work, and probably you wouldn't have been looking at 397 (or what ever it was) HP out of a hyd roller cammed 455. From my testing, a small valve G head bone stock has enough flow to support an easy 440 HP with a hyd roller, with the cross over filled and the divider welded, at 9.1 comp, what happened? Valve float happened, along with probably other things. Now I know in all your hardcore engine building experiance you wont consider what im saying, but please feel free to critique my up coming 455 build, the proof will be in the results.

 

ihengineer76...your so right,that's what it's all about.

 

I guess we'll see.
Please don't compare a bbc vs a Bbo.
Head flow, combustion chamber and bore and strike are not the same, that bbc will flow better assembled because of its larger bore alone.
And you might want to consider 2 things, 1 is if the valves were floating why did it pick up power when we added the spacer? And 2, lifter valving also dictates how much spring pressure you can use. But you already knew that right?
Still need an answer to the first question, I'm dying to hear how you explain that.

 

Fair enough, This 455 build is coming up, we then can compare apples to apples.

 

You still need to inform us how installing a carb spacer suddenly helped "valve float". We're all ears.

And unless your motor is done on the same dyno as mine was then there is still a margin of error. But you knew that right?

 

Still waiting for your carb spacer vs valve float explanation.

Oh yes, on the next dyno run you do, why don't you do it at a water out temp of 160+, not 133 or so. I promise you your Hp/tq numbers will change, especially on an iron headed application. But again you knew that right?
For the record mine are all done at 160+, much more real world than your 130 and change.

And by the way, how are you making 520hp with only 190#'s of fuel?

 

"Milling the divider will make more peak HP with a 750 carb, if you can fit a 1 inch open spacer it will also accomplish the same goal,"

Not trying to add any drama (more than enough already) I am confused.
Maybe I missed something(?) as VortecPro is saying a spacer adds HP.
Then you say "no it won't" but go on to say "picked up 14hp" ?
Please set me straight so I understand.

edit* the more I read maybe its the carb size that is in question?

 

Yes

He stated that simply adding a spacer will have the same effect as cutting the divider, not true, two different things.
Editted - When cutting the divider you're really not adding any volume to the plenum, it's already there. Just like walking thru a foyer that spans two rooms with a wall between the 2 rooms. Tear down the wall between them and it opens it all up, but you really didn't add any space.
Now make the foyer bigger and you've added space, whether the divider wall between the rooms is still up or not.

That's the difference between adding a spacer or just cutting the divider down.

Hope this helps.

 

]Mark, let me address your questions. 1. When the engine is in valve float all testing becomes null and void, atleast in my opinion. 2.Right now Im out of town racing, but when I get back I will post a dyno test from the same type of 467 tested at a higher temp, you are correct, lower temps on an iron head usually means more HP, but not much, but on this engine using speedpro coated pistons HP is usually a little higher with more temp due to piston to wall clearence. 3. Im making 519 HP corrected to 29.92 60 degrees dry air on a SF 901 with wyndyn software allways calibrated. Fuel flow is allways measured off the observed or in the room number. And please remember my dyno sits at a physical elevation of 6400 feet, baro runs from 23.4-24.00. A good book on dyno testing is available, Harold Bettes is the author, and it explains and adresses most questions on dyno testing. I enjoy our give and take, I will do my best to answer your questions.

 

If the valves are floating how do you make 14hp more by just changing spacers? You keep side stepping your own statement.
Doesn't compute dude.

And 519 "corrected" should use a whole bunch more fuel than that, period. Plus now you're saying that it would be higher than that at sea level? On an peanut headed bbc with the specs you mentioned? No fricken way, sorry. You have a very, very happy dyno.

 

Description of work and observations
During the assembly of a BBC engine, client requested that the bore and stroke measurements be verified as well as the casting number of the cylinder heads and the number on the crankshaft. I also verified the flow data sheets on the cylinder heads that were used on this particular build. I took several digital photos and took notes on the engine dimensions and casting numbers. I personally calibrated the torque system on two separate occasions at the request of the client. The first calibration was done a few days prior to the final test session on March 1, 2008. The first session was uneventful and I used the weights on site and used the numbers written on each weight.
On the last test session prior to running the BBC engine on March 1, 2008, I used my own scale to verify all his calibration weights and brought two additional lab weights of my own. This calibration was also uneventful, but required a very slight change in calibration values based on my calibrated scale. Thehysteresis and the linearity of the torque system were checked and were well within specification. The torque system was checked to in excess of 423 lb-ft. The barometric pressure was verified as well as the vapor pressure and temperature readings on the dynamometer.


Report on work done at Mark Jones’ shop (continued page 2 of 2)
By Harold Bettes
3/4/2008


Data Section Measured Bore = 4.350”
Measured Stroke = 4.00”
Calculated displacement = 475.58 cubic inches
Casting number on cylinder heads = 346236 (cast iron)
Casting number on crankshaft = 7416
Camshaft grind number = Iskenderian Mega 280
Cylinder head flow = 282 – 292 CFM (@ 28”H2O)
Fuel = Loaf and Jug pump gasoline
All testing done at acceleration rate of 300 RPM/sec

Conclusions and Comments
Over the course of several hours on client’s site on March 1, 2008 I observed many dynamometer tests as the client was tuning the engine to get to a point of best performance. The maximum corrected brake horsepower numbers varied between 525 and the last several pulls at 535 and 541 CBHp.

Although I observed the testing, I did not keep any of the data other than the notations that I have listed above. The client (Mark Jones) has the complete printouts from all those tests and I will leave it to him to publish the data as he sees fit as much of the data he might consider proprietary.

This report is submitted to the client (Mark Jones) for his use as he sees fit. Other information considering this work is not available unless Mark Jones directs said disclosure to be allowed. This would include digital photos and various engine building and tuning details observed by this author that Mark Jones might consider as proprietary.

End of report.
HB2
Power Technology Consultants
Colorado Springs, Colorado

 

Ok I'm going to ask one more time, I didn't see an explanation in there in how I picked up
14hp with just a spacer change and how that effected the "valve float.
Are you, or have you ever been a politician? You sure act like it. And plain and simple, your math doesn't jive on your dyno runs, sorry.
Until you answer the question I've asked 3 or 4 times now, I'm done here.

 

Mark, I dont acknowledge any of the data from your dyno tests because of the valve float, how can you test a carb spacer when the engine is in valve float by 4800 RPM, theres no way to determine the benifits from the spacer because you cant rev the engine out, their your dyno sheets not mine, how does a 455 inch engine with a 228 @ .050 hyd roller only make 397 HP, and peak below 4900 RPM? Again fuel flow is based off observed HP, not corrected HP. Observed HP on your dyno tests were in the 360 HP range if I remember right, I ran the numbers last week, I dont have a calculator with me now. You do not understand how the dyno works, Im trying to tell you, but you wont listen. Heres the bottom line, just for instances like this, Ive got this 3720 pound small tire chevelle I test these engines in, this 519 HP 467 that I posted the dyno test, whats it run in this chevelle??? Honestly Mark, try and open your mind up and learn something here.

 

Not a politician, just a machinist/ head porter/ engine builder/ tester on the dyno then the car.

 

So what did the 519 HP in the Chevelle run?

 

119.8 MPH @ give or take a pound or two @ 3720 27.90 baro, 2900 feet DA, 1968 Chevelle, which is the car I use to test various engine combinations, 3 speed automatic, 4.10 gear, (for that test) 30x9 radials, exhuast, no power steering, drum brakes, Factory interior.

 

Ok, for the last time, if the engine is in valve float then wouldn't you think that no matter what you did it wouldn't effect hp?
If you have a misfiring engine and you add a bigger carb do you think you'd put up better numbers even at the point of misfire?

And it only put out 397 because of crappy heads and a carb that was too small.

BTR did a 496 BBO with Edelbrocks, 10:1 and a 238@ .050 roller with nearly .600 lift, it made 540, that's it. Are you going to say he had valve float and he didn' know what he was doing either? Personally I don't care for the guy but as an engine builder he's certainly one of the better ones.

You can make 550 easy with a 454 Chevy and Edelbrock heads, not on an Olds. Olds heads aren't the best, if you haven't figured that out yet.

http://72.22.90.30/phpBB2/viewtopic.php?t=83659

 

Ive raced the Olds in the eighties, and early 90s, F/SA D/SA, never had any of those engines on a dyno, so maybe I have a big bad surprise coming when I build mine, please dont misunderstand me, Im not saying a 455 will run with a big block, production parts to production parts. That Edelbrock head really doesnt move any air as cast, as I learned from your flow test. What Im looking at on your test is how the BSFC takes off after around 4800 RPM. My 455 build an engine test is coming, lets see what I can do, maybe it will be horrible, but I will share the results with this forum, and we can critique away.

 

Are you going to answer the question or not?

Here's another build;
http://highperformanceolds.com/phpbb...hp?f=14&t=2657

Take this one and the one above and multiply the pounds of fuel per hour by 2.4, and you'll see that on both builds it equals the listed hp. That equals a bsfc of approx .42.

So why is it that yours is much closer to 2.8, i.e. 190# x 2.8= 532. Your bsfc is closer to .36. That means that you're making more power on less fuel than anyone else on the planet. Man you're good! Why weren't you in the EMC???????? Wow!!!!

Something ain't right. So why would we believe any numbers coming from that dyno?

I wouldn't.

P.S. I know exactly why my bsfc went to the sky towards the end, do you?
I'll even be a nice guy and give you some info to use for your answer, if you decide to actually give one.

Carb was a Quick Fuel 750, we were pulling 2" of vacuum at wot, so mister engine builder, racer, dyno master, any idea why my bsfc went to the moon towards the end and not beforehand? And why I couldn't make a simple change?
If you answer this one correctly right away I'll cut you some slack. Clock is running.

Done here.

 

Mark, I thought you understood from my PMs that I really don't care about mph just ET. Was just curious because my 380 produced 518 HP.

 

Nick, he's not going to answer you. Don't most people give an et when they give all their run info? Why did he leave that one piece of info out? And why believe him anyway, I'd want to see a time slip.

Vortecpro- to quote the very funny David spade in tommy boy;
"hey lady there's a time limit"
Lol!!

 

Cut me some slack, you've got to be kidding. Its evident to me you have no idea what you are talking about, same thing on my ported G head thread. My dyno has been proven over and over and over again. Mark, you've fooled a lot of people on this site, your own dyno tests
proves exactley your skill as an engine builder/designer. You made it personel when you attacked my dynos accuracy. You have no idea what your getting yourself into. These cams you sell to the uninformed, are they cast or billet cores???????????

 

The engine was run 1 race in my car, best pass was 10.94 @ 119.8, I dont remember the 60, but it probably was in the mid 1.4s.

 

Carb is too small if you're drawing 2" of vacuum at WOT. What do I win Johnny?
Should be closer to zero if sized right if I remember correctly.

 

OOO Boy this is getting exciting!!!

 

I think Mark believes the BSFC took off after 4800 RPM because the engine was pulling vacuum at wide open throttle, thats not the case, thats simple valve float, is there anyone out there that thinks 135 on the seat and 325 open is going to control a 228@.050 hyd roller with .570 lift, it will not in my opinion, and his own dyno test proves it. How could any engine builder be happy with a 455 with bowl work, filled heat crossover, 228@.050 hyd roller, aftermarket intake, 750 Holley, 9.1 compression, that makes 397 HP @ a valve floating 4800 RPM, and an observed or in the room HP of 360, and you have the ***** to try and tell me somethings not right.

 

You could learn something here yourself, probably you should pay attention.

 

True to form, you didn't answer any of my questions, so who's the fool.

The cam cores are either Sadi 1050's or Crane 8620's, the same material used for Chevys, Fords etc. But you knew that right.

You're full of bull***** you haven't answered one of my questions, I've answered all of yours.

You're a total and complete blowhard, and there are more than a few on here that see right thru you.

So let's recap;
Your dyno numbers don't make any sense, if they do then please explain, but we know you won't.
You haven't answered one of my questions.
And you continue to throw stones yet you have no substantiation on anything.

I have no time for blowhards like you, I'm done here.

I'm sorry did I mention that you're full of shyt and you're a blowhard

 

Description of work and observations
During the assembly of a BBC engine, client requested that the bore and stroke measurements be verified as well as the casting number of the cylinder heads and the number on the crankshaft. I also verified the flow data sheets on the cylinder heads that were used on this particular build. I took several digital photos and took notes on the engine dimensions and casting numbers. I personally calibrated the torque system on two separate occasions at the request of the client. The first calibration was done a few days prior to the final test session on March 1, 2008. The first session was uneventful and I used the weights on site and used the numbers written on each weight.
On the last test session prior to running the BBC engine on March 1, 2008, I used my own scale to verify all his calibration weights and brought two additional lab weights of my own. This calibration was also uneventful, but required a very slight change in calibration values based on my calibrated scale. Thehysteresis and the linearity of the torque system were checked and were well within specification. The torque system was checked to in excess of 423 lb-ft. The barometric pressure was verified as well as the vapor pressure and temperature readings on the dynamometer.


Report on work done at Mark Jones’ shop (continued page 2 of 2)
By Harold Bettes
3/4/2008


Data Section Measured Bore = 4.350”
Measured Stroke = 4.00”
Calculated displacement = 475.58 cubic inches
Casting number on cylinder heads = 346236 (cast iron)
Casting number on crankshaft = 7416
Camshaft grind number = Iskenderian Mega 280
Cylinder head flow = 282 – 292 CFM (@ 28”H2O)
Fuel = Loaf and Jug pump gasoline
All testing done at acceleration rate of 300 RPM/sec

Conclusions and Comments
Over the course of several hours on client’s site on March 1, 2008 I observed many dynamometer tests as the client was tuning the engine to get to a point of best performance. The maximum corrected brake horsepower numbers varied between 525 and the last several pulls at 535 and 541 CBHp.

Although I observed the testing, I did not keep any of the data other than the notations that I have listed above. The client (Mark Jones) has the complete printouts from all those tests and I will leave it to him to publish the data as he sees fit as much of the data he might consider proprietary.

This report is submitted to the client (Mark Jones) for his use as he sees fit. Other information considering this work is not available unless Mark Jones directs said disclosure to be allowed. This would include digital photos and various engine building and tuning details observed by this author that Mark Jones might consider as proprietary.

End of report.
HB2
Power Technology Consultants
Colorado Springs, Colorado
I find it hard to believe your done.My engines make power, and thats just fact.

 

Yes just don't listen to VTP.

O.k as usual I'll answer your questions right away, we know you'll need to call someone to answer the ones I ask you.

To benefit all, the reason it I had such a high bsfc at the upper end is because of the fact that I was pulling 2 inches of vacuum.
What did that do? Simple, When you have vacuum like that it pulls fuel from the power valve circuit. I couldn't make a jet change because it wasn't rich across the whole power curve, just when it started pulling vacuum, as the rpm increased. To make a jet change there it would have gone lean until it started pulling vacuum, consequently pulling fuel from the power valve circuit.

But with all that has been said, I'm really looking forward to the 850 Proform carb that's going on that 455 to take care of the valve float. Lol!!

So all you guys with Olds engines with 40 year old valve springs, don't worry about valve float, just put a bigger carb on it.
By the way VTP, you still haven't answered how I got more hp with a spacer. Oh that's right, it cured the valve float, albeit for just a minute.

You're a total and complete blowhard.

P.S. I believe you said that BBC was a 467, but wait, the specs are 4.350x4.00. Wait a minute that equals 476 not 467. More bullshyt.

This will be my last post on this thread.