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Anonymous
Guest
yea, i just put mine on the top of my steering column, got a small one so it only covers the odometer
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Anonymous
Guest
man i wish i had a 100mph speedometer so i could top it out, lol
Aside from parts that make the engine duarble enough to rev that high, in order to make useful power at that rpm, you need two things.
First is airflow. The intake and exhaust systems, ports, and valves need to be sized to be able to provide enough volume and velocity to take care of the engine's needs at that speed.
The second thing is a cam designed to provide useful power at that level. Most cams have a hp curve that starts to fall off after 5500 rpm. By 6500 you may be making less hp than you do at idle. You'll have to cam the engine to move the power curve to be usefule at that level.
Generally, a cam that makes lots of power at 6500 is less streetable than a cam that makes max power at 4500.
First is airflow. The intake and exhaust systems, ports, and valves need to be sized to be able to provide enough volume and velocity to take care of the engine's needs at that speed.
The second thing is a cam designed to provide useful power at that level. Most cams have a hp curve that starts to fall off after 5500 rpm. By 6500 you may be making less hp than you do at idle. You'll have to cam the engine to move the power curve to be usefule at that level.
Generally, a cam that makes lots of power at 6500 is less streetable than a cam that makes max power at 4500.
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Anonymous
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I would be interested if anyone has been able to get an Ozz 250 to make its "peak" output in HP at any higher level than 4800 rpm and can back the claim. Maybe today it could be done today but through the 70s one Ford engineer did a lot of dynoe work on the 250 and he was unable get it to. I am faily sure he said it was due to the rod ratio.
Mind you 4800 is plenty high enough if you do the gear change a bit latter.
Mind you 4800 is plenty high enough if you do the gear change a bit latter.
Rod ratio certainly plays into the equation, but that's not the driving factor. I've seen small block 400 ci chevys and hybrid 373 SBC'c with 400 crank and rods, revved past 6000 rpm, and they have very poor rod ratios (about 1.48 IIRC).
OTOH, if you look at a flathead Ford with its 7" rods, it has a great rod ratio, but no ability to rev beyond 4500 or so in stock form due to severe airlflow restrictions. You'll probably see that at about 4500, the stock Ford inline six runs out of breath due to cam and head limitations.
It's not been on a dyno, but I have revved the Crossflow to 6000, but power falls off at about 5000 so there is no need to subject the enginen to that kind of stress.
OTOH, if you look at a flathead Ford with its 7" rods, it has a great rod ratio, but no ability to rev beyond 4500 or so in stock form due to severe airlflow restrictions. You'll probably see that at about 4500, the stock Ford inline six runs out of breath due to cam and head limitations.
It's not been on a dyno, but I have revved the Crossflow to 6000, but power falls off at about 5000 so there is no need to subject the enginen to that kind of stress.
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Anonymous
Guest
I agree it probably hasnt got much to do with the ratio. And its sure to make a big differnce if they did the test on the 250 2V rather than the log head six (I assume it was the former) .Diifferent cam,carb and extraction were used with the same result.
Around 5000 would be a safe bet and if power didnt drop of too sharply it may be worth reving a bit more to allow for the drop in rpm when the next gear change occured.
Around 5000 would be a safe bet and if power didnt drop of too sharply it may be worth reving a bit more to allow for the drop in rpm when the next gear change occured.
This a bit of a ramble (suprised anyone?), but what it says applies to all Falcon sixes with short rods...US 200, Argie/Aussie 221 US 250, Aussie 250, Aussie SOHC3.9, 4.0, and DOHC 4.0.
I have my own views, having read most of Bill Santuccione stuff. He's the ex Repco, ex Ford Australia development engineer who worked on the Aussie 250 and Cleveland V8 engines during the 60's and 70's. He now runs SVT in Melbourne, I think. He had a big hand in setting up the Quality Control run of 200 Homologation 351 HO 4V Clevelands for the Falcon GT's of the early 1970's.
Link is http://fordsix.com/forum/viewtopic.php?t=919&start=0&postdays=0&postorder=asc&highlight=
Another link, which was an all in "grey matter cage fight" between the "techno-gurus" Engineer StrangeRanger and budding university man XT 500 is also a very insightful link,
http://fordsix.com/forum/viewtopic.php?t=1658&start=0&postdays=0&postorder=asc&highlight=
NB// I've got copies of the graphs that have dropped off XT 500 link, if anyone want's them posted.
My understanding is that the rev range problem is more related to one carb serving six cylinders, and I do believe that frictional loseses are the rest of the peak power rpm issue. Mathematically, I think it can be proven. However, the latest BA DOHC six is only at a 1.53:1 ratio, and it takes VVT and tunned intake runners to hit the big 6000, but power flat-lines well before that, 4750 to 5250 is the maximum power level for all BA sixes. Same goes for the similarly long-stoked, short rodded 5.4 295 HP, 349 HP, and 389 hp V8'S. Power flat-lines well below 6000 rpm.
Bill clearly affirms what Jack and Tim and I know already. A Falcon six can rev well over 5000 rpm. I've seen 5300 rpm on mine, easily. Bill has had early 250 engines up to 7500 rpm under there own steam! The fact is, you can't push the maximum peak power rpm to 6500 unless you work up every other componet around the core issue...rod ratio. I guess a set of Triple IDA 48's, a 330 degree cam, and a 12.5:1 compression ratio will raise the peak power level, but it will not go up as much as on an engine with a better rod ratio. I think that was Bill's point. It wasn't that 4800 rpm was a mystical component limit with a 250.
One other point is, any engine that revs to any rpm will have a maximum torque figure 1.2 to 1.5 times lower than the maximum power figure. The maximum rpm figure is always 1.1 or so above the maximum power figure.
Eg 1:
If your engine runs to say 6500 rpm,
you are going to get maximum torque at 4200 rpm,
maximum power at 5900 rpm,
and on the street, it'll need a whole heap more gears, and revs, and gas to keep up with the lo-compression plodder 200 with maximum revs to 5000 rpm,
power at 4000 rpm,
torque at 2500 rpm.
Eg 2:
The reason drag racers get revs, is that they've developed the other components. A 514 Fraud or 502 Chev with a crook rod ratio doesn't need to rev to 8000.
I have my own views, having read most of Bill Santuccione stuff. He's the ex Repco, ex Ford Australia development engineer who worked on the Aussie 250 and Cleveland V8 engines during the 60's and 70's. He now runs SVT in Melbourne, I think. He had a big hand in setting up the Quality Control run of 200 Homologation 351 HO 4V Clevelands for the Falcon GT's of the early 1970's.
Link is http://fordsix.com/forum/viewtopic.php?t=919&start=0&postdays=0&postorder=asc&highlight=
Another link, which was an all in "grey matter cage fight" between the "techno-gurus" Engineer StrangeRanger and budding university man XT 500 is also a very insightful link,
http://fordsix.com/forum/viewtopic.php?t=1658&start=0&postdays=0&postorder=asc&highlight=
NB// I've got copies of the graphs that have dropped off XT 500 link, if anyone want's them posted.
My understanding is that the rev range problem is more related to one carb serving six cylinders, and I do believe that frictional loseses are the rest of the peak power rpm issue. Mathematically, I think it can be proven. However, the latest BA DOHC six is only at a 1.53:1 ratio, and it takes VVT and tunned intake runners to hit the big 6000, but power flat-lines well before that, 4750 to 5250 is the maximum power level for all BA sixes. Same goes for the similarly long-stoked, short rodded 5.4 295 HP, 349 HP, and 389 hp V8'S. Power flat-lines well below 6000 rpm.
Bill clearly affirms what Jack and Tim and I know already. A Falcon six can rev well over 5000 rpm. I've seen 5300 rpm on mine, easily. Bill has had early 250 engines up to 7500 rpm under there own steam! The fact is, you can't push the maximum peak power rpm to 6500 unless you work up every other componet around the core issue...rod ratio. I guess a set of Triple IDA 48's, a 330 degree cam, and a 12.5:1 compression ratio will raise the peak power level, but it will not go up as much as on an engine with a better rod ratio. I think that was Bill's point. It wasn't that 4800 rpm was a mystical component limit with a 250.
One other point is, any engine that revs to any rpm will have a maximum torque figure 1.2 to 1.5 times lower than the maximum power figure. The maximum rpm figure is always 1.1 or so above the maximum power figure.
Eg 1:
If your engine runs to say 6500 rpm,
you are going to get maximum torque at 4200 rpm,
maximum power at 5900 rpm,
and on the street, it'll need a whole heap more gears, and revs, and gas to keep up with the lo-compression plodder 200 with maximum revs to 5000 rpm,
power at 4000 rpm,
torque at 2500 rpm.
Eg 2:
The reason drag racers get revs, is that they've developed the other components. A 514 Fraud or 502 Chev with a crook rod ratio doesn't need to rev to 8000.
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Anonymous
Guest
I got a isky 280 cam forsale its range is from 2500-6500 rpm $130
I am looking into rebuilding a new engine and i wanted to make it stronger so i could rev it up a little more. I plan on getting it balanced, arp rod bolts, forged rods, forged pistons(nitrous later 
) i will get it all balanced and blue printed, new harmonic balancer, better valve springs, retainers. Is there any thing i am forgetting, I will also have the block bored, but i dont know how much and deck it to zero deck height or flat top pistons. I also want a new cam that might give me a little more power, i am waiting for those dual grind cams for the aussie head!!!
Now here are my questions Where can i get these parts, the forged pistons and the Rods. Also is there any thing else the mechienist should do. I am unhappy with the place that did my head, so i am gonna go around town and look for an old guy that has been doing this stuff for years and i think i will get a better resualt then some kid that really doenst care. IF you have any suggestions i am always open for new ideas, well i dont want a JATO but any thing eles!
kevin
) i will get it all balanced and blue printed, new harmonic balancer, better valve springs, retainers. Is there any thing i am forgetting, I will also have the block bored, but i dont know how much and deck it to zero deck height or flat top pistons. I also want a new cam that might give me a little more power, i am waiting for those dual grind cams for the aussie head!!!Now here are my questions Where can i get these parts, the forged pistons and the Rods. Also is there any thing else the mechienist should do. I am unhappy with the place that did my head, so i am gonna go around town and look for an old guy that has been doing this stuff for years and i think i will get a better resualt then some kid that really doenst care. IF you have any suggestions i am always open for new ideas, well i dont want a JATO but any thing eles!
kevin
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Anonymous
Guest
you can get the forged rods from an older inline six 200 and the pistons are gonna have to be custom made.
Alex":3ax543eq said:
My info says that factory 200 rods from 1965-1975 are forged steel, the 1976-1979 rods are cast steel, and the 1980-1982 rods are high nodular iron. I think that is correct but Im too lazy to get up and go double check, its 1:30am.
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Anonymous
Guest
Just wanted to mention. Today I was fkin around with the stang and well I just had to let the little engine rip. 8) revved it up to about 6500. Not necessarily 6500 for any reason other than I got scared as hell after I saw that needle blast all the way up there and damn was it loud, not really earth shaking loud, more like window shattering loud.
I bet the damn thing could've gone all the way to 8 or 9k if I had let it. This engine breathes so well now that it can rip itself to pieces.
I won't be doing that any more, just one of those things that I had to do at least once in my life.
I kindof figured I'd float the valves but possibly not because my shop installed valve springs that are probably quite a bit stronger than they need to be. :roll:
I hope I didn't break it but If I did then I wouldn't care all that much, I'd rather have a 250 in there anyway, I just hope I don't end up breaking my 2v head. That would suck.
I bet the damn thing could've gone all the way to 8 or 9k if I had let it. This engine breathes so well now that it can rip itself to pieces.
I won't be doing that any more, just one of those things that I had to do at least once in my life.
I kindof figured I'd float the valves but possibly not because my shop installed valve springs that are probably quite a bit stronger than they need to be. :roll:
I hope I didn't break it but If I did then I wouldn't care all that much, I'd rather have a 250 in there anyway, I just hope I don't end up breaking my 2v head. That would suck.
