D.U.I INSTALLED WITH DYNO RESULTS AND PICS
- Thread starter mraley
- Start date
I think one reason people are often a little underwhelmed with the HP gain of a 2V/200 setup is the huge inlet ports. You need serious RPM to develop a flow that can really make them work. The longer stroke of a 221 or 250 seems to be just enough to actually get this aspect working for you.
It still needs to rev but it will work (more) nicely. Maybe Mike could look at importing 221 shortblocks from Argentina? They are so close in size and weight to the 200. Plus, the DUI will fit straight in.
Cheers, Adam.
It still needs to rev but it will work (more) nicely. Maybe Mike could look at importing 221 shortblocks from Argentina? They are so close in size and weight to the 200. Plus, the DUI will fit straight in.
Cheers, Adam.
Those are great results! I know what I am saving up for now. Hopefully, I can have one in before Hot August Nights. I just spent my DUI money on some adjustable strut rods.
A log to Oz head swap doesn't produce much by itself. From my own experience you have to also swap cams to get a bigger impact.
A log to Oz head swap doesn't produce much by itself. From my own experience you have to also swap cams to get a bigger impact.
A
Anonymous
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ya those numbers are awsome. I currently have no cash with the house and school but the new DUI and a decent 2brl are on my list of first performance mods. And some day the new head from FSPP 
But good job guys and keep the info flowin; so us POOR students dont waist our money on the wrong performance parts.
But good job guys and keep the info flowin; so us POOR students dont waist our money on the wrong performance parts. 
michael_cini
Well-known member
I don't understand why some people are disappointed with the 20 hp gain with the 2v head. I recall seeing some original specs from the Aussie's that the difference between the 70's pre-crossflow 250 log and the 250 2v was only a 20 hp bump up, so why be surprised now?
AzCoupe":qe27b901 said:I was also disappointed with the small gains from the OZ swap. The next step, will be another dyno day, with the new aluminum head and 4V.
Ragtopman,
There is more to the DUI than just raw HP/TQ numbers. I put one of their units in my '68 Catalina convertible with a 400-4V. The idle quality and just all around smoothness to the engine is worth the price IMHO. The "drivability" of the DUI is so much better than the stock ignition.
tanx,
Mugsy 8)
There is more to the DUI than just raw HP/TQ numbers. I put one of their units in my '68 Catalina convertible with a 400-4V. The idle quality and just all around smoothness to the engine is worth the price IMHO. The "drivability" of the DUI is so much better than the stock ignition.
tanx,
Mugsy 8)
HowdyAgain MRaley:
Last time I posted I said "Last question" I guess I lied, but I've been thinking on the before and after comparison and have more questions. I hope you don't mind.
Did the compression ratio change between the Log and the Oz head swaps?
Is the 264 cam degreed start up?
As several have already stated the increase in HP and torque is so surprizing that I have to look for a better explanation then just ambient temperature (although, I'm sure that is part of the answer). If the head alone had accounted for the figures, I'd accept it, but the addition of the Holley 350 could, if properly tuned and direct mounted on your engine, account for most of that increase alone.
Adams observation about port size cause me to think that the real HP may be above the capabilities of this cam(?). If the cam is currently straight up, you might want to consider advancing it 4 degrees to get it to come in higher in the rpm range, to take advantage of the breathing ability.
I'm also mystified at the increases attributed to the DUI ignition. The only thing I can figure is that your DS II curve was less then exact and the DUI hit the mark. Tuning is all the difference.
Once again, results point out that an engine is a package. All parts must be planned for a specific goal.
Again, thanks for sharing.
Adios, David
Last time I posted I said "Last question" I guess I lied, but I've been thinking on the before and after comparison and have more questions. I hope you don't mind.
Did the compression ratio change between the Log and the Oz head swaps?
Is the 264 cam degreed start up?
As several have already stated the increase in HP and torque is so surprizing that I have to look for a better explanation then just ambient temperature (although, I'm sure that is part of the answer). If the head alone had accounted for the figures, I'd accept it, but the addition of the Holley 350 could, if properly tuned and direct mounted on your engine, account for most of that increase alone.
Adams observation about port size cause me to think that the real HP may be above the capabilities of this cam(?). If the cam is currently straight up, you might want to consider advancing it 4 degrees to get it to come in higher in the rpm range, to take advantage of the breathing ability.
I'm also mystified at the increases attributed to the DUI ignition. The only thing I can figure is that your DS II curve was less then exact and the DUI hit the mark. Tuning is all the difference.
Once again, results point out that an engine is a package. All parts must be planned for a specific goal.
Again, thanks for sharing.
Adios, David
Jamyers,
Good point about the DUI versus the multistrike box. I have never ran a spark box.
As for whats makes it work.. I *think* the larger gap and spark quality is the secret here. In the Cat the spark plug gap went from 0.035 to 0.055. The larger gap (read:spark) results in better combustion. The other thing I noticed was that at idle the "miss" that happened every once in a while is gone. The electronics fire each cylinder, each time. The engine just runs smoother...
So let me ask, do you have a 200 in your car? Will you be able to try one out?
tanx,
Mugsy 8)
Good point about the DUI versus the multistrike box. I have never ran a spark box.
As for whats makes it work.. I *think* the larger gap and spark quality is the secret here. In the Cat the spark plug gap went from 0.035 to 0.055. The larger gap (read:spark) results in better combustion. The other thing I noticed was that at idle the "miss" that happened every once in a while is gone. The electronics fire each cylinder, each time. The engine just runs smoother...
So let me ask, do you have a 200 in your car? Will you be able to try one out?
tanx,
Mugsy 8)
Mraley,
The 500 on my direct mounted carb on the log is much stronger than the 350 carb.
Use 68 main jet size with a 8.5 power valve & reduce the power valve restriction-
You need to put a holley 4412-500 carb on your setup, I noticed a very good increase in power just from my direct mount log head going from the 7448-350 to the 4412-500 carb.
With the 4412, go with a 68 main jet, a 8.5 power valve & change the power valve restriction PVRV under the power valve to .055 instead of the stock .0625 which is too rich with full throttle.
These tests were done using an innovate air fuel ratio tester.
This restrictor needs to be drilled & tapped to use a 6-32 screw in set screw drilled to .055.
This brass screw in orifice is available from mcmaster-carr #92991A142 404-346-7000, remember you have to drill the brass plug for your desired demension.
Put the 4412 on and see the increase. You have the right combination it just needs to be upgrated to the 500-4412 carb.
Try it you will like it. William
The 500 on my direct mounted carb on the log is much stronger than the 350 carb.
Use 68 main jet size with a 8.5 power valve & reduce the power valve restriction-
You need to put a holley 4412-500 carb on your setup, I noticed a very good increase in power just from my direct mount log head going from the 7448-350 to the 4412-500 carb.
With the 4412, go with a 68 main jet, a 8.5 power valve & change the power valve restriction PVRV under the power valve to .055 instead of the stock .0625 which is too rich with full throttle.
These tests were done using an innovate air fuel ratio tester.
This restrictor needs to be drilled & tapped to use a 6-32 screw in set screw drilled to .055.
This brass screw in orifice is available from mcmaster-carr #92991A142 404-346-7000, remember you have to drill the brass plug for your desired demension.
Put the 4412 on and see the increase. You have the right combination it just needs to be upgrated to the 500-4412 carb.
Try it you will like it. William
mraley
Well-known member
WSA111.....You really are sold on that 500, huh?
I've only had the 350 for about 8 months or so. It's really hard to justify another carb. Do you know if I would have to do any other mods to install it? What I'm asking is if the linkages will match up with out any issues? Also, is the 500 any larger than the 350? I'm within an 1/8" of the shock tower and have nowhere else to go. Michael
I've only had the 350 for about 8 months or so. It's really hard to justify another carb. Do you know if I would have to do any other mods to install it? What I'm asking is if the linkages will match up with out any issues? Also, is the 500 any larger than the 350? I'm within an 1/8" of the shock tower and have nowhere else to go. Michael
wsa111
on a different thread you stated
"With the 500-4412 this carb should be used on a direct mount to the log & use a 68 main jet, 6.5 power valve & insert a .010 wire in the PVRC-power valve restriction orifice. Doing this will give you a 14.7 cruise air fuel ratio & a 12.3 full throttle air fuel ratio. The idle should be in the 13.5 area. "
now you are saying to use the 8.5 power valve.
which one in your opinion would be the better one? I have a 4412 and was going to switch to the 6.5pv and a 69 jet ( couldn't get a 68 )
earlier my wife had bought me a demon 4bbl 525 carb and i would love to try that but have been told that it is to much carb. it specs out at
58 primary main jet and 6.5 pv with 74 sec jet, PVCR size is .059
the tag on the carb says idle flow 65% and wot flow 230 PPH ( does anybody know what that means)
Is it too much carb (it looks really nice) if so i will mess around with the 4412.
thanks
John
on a different thread you stated
"With the 500-4412 this carb should be used on a direct mount to the log & use a 68 main jet, 6.5 power valve & insert a .010 wire in the PVRC-power valve restriction orifice. Doing this will give you a 14.7 cruise air fuel ratio & a 12.3 full throttle air fuel ratio. The idle should be in the 13.5 area. "
now you are saying to use the 8.5 power valve.
which one in your opinion would be the better one? I have a 4412 and was going to switch to the 6.5pv and a 69 jet ( couldn't get a 68 )
earlier my wife had bought me a demon 4bbl 525 carb and i would love to try that but have been told that it is to much carb. it specs out at
58 primary main jet and 6.5 pv with 74 sec jet, PVCR size is .059
the tag on the carb says idle flow 65% and wot flow 230 PPH ( does anybody know what that means)
Is it too much carb (it looks really nice) if so i will mess around with the 4412.
thanks
John
John, further testing I found the 8.5 power valve filled in a lean hole on partial acceration & improved drivability considerabbly.
I also leaned down the pvcr to .055 to lean out full throttle air fuel mixture.
Thanks for asking, William
I also leaned down the pvcr to .055 to lean out full throttle air fuel mixture.
Thanks for asking, William
Howdy back Michael and all:
The 4412 and the 7448 ar the same size externally. The differences are on the inside. The linkage will be identical too. Variables might be auto/manual choke and possibly the addition of a Ford kickdown linkage addition for some trans.
John- The selection of the power valve will depend on the vacuum characteristics of your engine in your environment. Bill has the advantage of accurate feedback with his Innovate Air/fuel meter.
You may know that the power valve is basically a vacuum switch. It determines when the additional fuel of the power circuit is delivered- not how much. How much is determined by the Power Valve Channel Restriction (PVCR) built into the metering plate. Opening the power valve sooner by switching to a higher number, or a number closer to cruise/ steady state vacuum, caused the power circuit enrichment to begin sooner, in Bill's case, eliminating a lean spot in the transition from cruise to WOT.
Sorry, can't help you on your Demon. They are good looking. In genereal, they are basically a Holley design- with more refinements.
Adios, David
The 4412 and the 7448 ar the same size externally. The differences are on the inside. The linkage will be identical too. Variables might be auto/manual choke and possibly the addition of a Ford kickdown linkage addition for some trans.
John- The selection of the power valve will depend on the vacuum characteristics of your engine in your environment. Bill has the advantage of accurate feedback with his Innovate Air/fuel meter.
You may know that the power valve is basically a vacuum switch. It determines when the additional fuel of the power circuit is delivered- not how much. How much is determined by the Power Valve Channel Restriction (PVCR) built into the metering plate. Opening the power valve sooner by switching to a higher number, or a number closer to cruise/ steady state vacuum, caused the power circuit enrichment to begin sooner, in Bill's case, eliminating a lean spot in the transition from cruise to WOT.
Sorry, can't help you on your Demon. They are good looking. In genereal, they are basically a Holley design- with more refinements.
Adios, David
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