Your max rpm for your big block????

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T67POWER

T67POWER

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How high do you rev your big block and what did you do to improve the oiling system if anything???
THANKS FOR ANY INFORMATION.:thumblef:
 
Till it blows up :twisted: But nah, 6500 redline is a good rule of thumb.
 
All depends. I do the same mods as the small blocks... higher relief pressure, standard displacement pump, MP drive, enlarge the main feeds, blend the sharp turn in the pickup fed passage, make sure clearances are good and there's minimal taper. Depending on the parts, the build, and the need, that will take it safely to 6500-7K. But above 6500, you really need to pay attention to block machining, main webbing, and bobweights. The stock botton ends are pretty bulletproof to about 6K if the machining is good.
 
Pictured is a ten quart pan on my Charger that I tig welded from an old 2 bulb flouresent light fixture. It's fully baffled with a windage tray.
I also use a remote dual oil filter but ADD a second return line and plumb/adapt it so it directs oil straight towards the rear passenger side lifter gallery ( where the two threaded holes are at the back of the block behind the intake ....oil pressure sending unit location) and restrict the drivers side lifters with a small piece of 3/8 or 5/16 rod ...approximately 90% blocked/restricted . I currently run a MP .528 solid cam.
I would use less of a restriction with a hydraulic cam though .

Completely stock bottom-end has been up to 7000rpm's a couple of times but mostly shift at 6500 (stock heads are tapped out by 6000 rpm but I'm planning on installing a set of fully ported Max wedges that should be good til at least 7 grand in the near future.


Currently in the 12's @ 110m.p.h. with just headers and a cam (and a lot of hill-billy engineering).
 

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doesn't it kinda depend on what the cam pulls power to?...or do you want to know what it will spin regardless of making power or not?
 
well using those external pickup oil pumps are a great start to keeping it alive over 7k.

as said before tho.... machining is huge, enough oil, light weight rotating assembly helps, 4 bolt mains or cradle to keep the caps from walking, near perfect balance
 
HEMIDENNY ...............
Just trying to see how high on an average, what people push big blocks to for rpm's with no problems.
I am building a 400 with a solid cam and want to use a high volume oil pump with a deep pan.
The only other thing i might do is install valve cover oil spray bars to keep the valve gear happy for those highway trips.
I always run low gears in my cars and have higher rpm"s all the time.
I won't go much past 6500 with the stock heads but when i go to a aluminum head i might want to bump it to 7000-7300 for shift points with install even more gear and converter.
 
I always liked the 383/440 motors for their grunt(torque), especially for pullin those B-bodys around...never like trying to twist the 440's much over 5500...the 383's we would spin a little higher....always wanted to use the torque and leave it to the small blocks to ring themselves ragged....that was always the beauty of those big cube Mopars ..because we didn't have to twist the hell out of em to make em go...we weren't always breaking/fixing them.The only thing I ever got out of adding big RPM to em' was a lighter wallet.Just my 2cents and you can have it for free(remember..you get what you pay for around here).
 
very nice Daredevil......I take it...your'e more in the "twist er' high and let er' fly" camp...looks like you got a good handle on it!
 
It's really a race for the weakest part.[trying to keep up with all the better parts]
Weakest link etc.......
I won't push it over 6500 and will most likely be shifting at 6200.
I will be using stock 452 ported cylinder heads.
It cost so much more money to get to that next level with any amount of durability.
Trying to make the torque as high in the band as possible so that the horse power is higher.
Everything has limits and keeping the engine in the range of the weakest link makes the weakest link sometimes ----not so weak.
Thanks again for the replies :drinkers: here's to ya
 

T67POWER said:
It's really a race for the weakest part.[trying to keep up with all the better parts]
Weakest link etc.......
I won't push it over 6500 and will most likely be shifting at 6200.
I will be using stock 452 ported cylinder heads.
It cost so much more money to get to that next level with any amount of durability.
Trying to make the torque as high in the band as possible so that the horse power is higher.
Everything has limits and keeping the engine in the range of the weakest link makes the weakest link sometimes ----not so weak.
Thanks again for the replies :drinkers: here's to ya
Click to expand...

most agreed! rpm kills durability... but on the flip side rpm=hp:thumblef:
 
When it pukes parts all over the track you know you've foud as far as it'll go.
 
I shift at 6500 have the soft touch set at 7,000. Engine revs so fast I'm into the limiter when the shift lite blinks and I shift.
I like Daredevil have the Milodon pump, external pick up, 8qt pan, and windage tray.
Eagle rods and crank, solid lifter cam, Harland and Sharp rollers
 

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hey....you never told us how big...your big block is....more importantly...what stroke you dealin' with?......i can feel in the pedal the difference between my 426 (std 3.75 stroke) and my 472 (4.15 stroke)....no more strokers for the street for me....I like the crispier revin' 426 over em' all...more than enough to twist the big drag radials.
 
The problems with a big block oil system are the same as small block. Leaks at the lifters if they are worn because the lifters get oil before the mains and rods, and the pickup side as the biggest restriction to oil flow. Instead of spray bars, you might want to just have the cam partially or fully grooved. The upper end oiling is good already, but not constant. Spray bars are for heads that have no rocker oiling built in.
 
moper....
If you grove the #4 journal of the cam so you have full time oiling then you have to install oil restrictors in the oil passages in the block.
In my max performance mopar big block book, it was suggesting to use spray bars as a means for additional oiling and also as a means of cooling the valve springs.
I guess it only takes about 5 pounds of oil pressure off your total oil pressure.

Andy finkbeiner also states in his book that when you grove the #4 cam journal you give even less oil to the #4 crank journal.
He has seen an engine with this set up spin the number 6 and 7 rod bearings in a dyno test, even though the back of the engine where the pressure was being measured showed a constant 70 pounds of oil pressure.
The more power we make the more problems rise up with stock blocks.
Most aftermarket blocks have addressed all these problems and are made with all the fixes already in the casting.

If you think about it,all the new parts made in the last 25 years or so have covered every part of the engine with new up to date, better performing parts that are starting to leave the factory castings in the dust.
Don't get me wrong,factory blocks are a great starting point for good street and drag engines, but if you have the money, you can over power a stock engine block with just a set of modern cylinder heads ,especially if you have already built a maximum effort engine with stock heads.
Thanks for the info and yes i could do that, but it turns in to a balancing act that in the end cost more time and money then i care to spend.
If i am going that far,then i will get an aftermarket block.
Any body have an extra 10 grand so i cam get started on my 850 horse big block???????

Ps Hemidenny..... I am building a 400 big block.
 
T67POWER said:
moper....
If you grove the #4 journal of the cam so you have full time oiling then you have to install oil restrictors in the oil passages in the block.
In my max performance mopar big block book, it was suggesting to use spray bars as a means for additional oiling and also as a means of cooling the valve springs.
I guess it only takes about 5 pounds of oil pressure off your total oil pressure.

Andy finkbeiner also states in his book that when you grove the #4 cam journal you give even less oil to the #4 crank journal.
He has seen an engine with this set up spin the number 6 and 7 rod bearings in a dyno test, even though the back of the engine where the pressure was being measured showed a constant 70 pounds of oil pressure.
The more power we make the more problems rise up with stock blocks.
Most aftermarket blocks have addressed all these problems and are made with all the fixes already in the casting.


Ps Hemidenny..... I am building a 400 big block.
Click to expand...

i call bs on this only from experience... these world hemi blocks that we use have so many issues right from the factory! usally have to spend another grand in machine work just to get the blok to where you can blue print it... cam and main bores are off, sand plugs still in water jackets, un-machined=no holes oil resticters in the block (top end oiling runs off of lifter galley no longer #4 cam)

they should be sold as a rough machined block...
 
You're right on the restriction if you fully groove. However you can also make the grooves very small, or only partially groove them. As you've talked about running the HV pump the extra volume "shouldn't" be a problem assuming the pickup side isnt a big hinderence. If you're running a quality spring I don't believe you need to worry about cooling them. You are talking about drag racing, correct? Or are you planning to road race this thing for extended time at these rpms?
 
7200 rpm in 1/4,stock bottom end,fully groved mains,deep pan,balanced 440, d.c. solid cam,car was weekend driver sometime track
 
I wont take my stock components over 6500,but the heads fully ported are capable of soo much more. Eventually the bottom end will get upgraded with K1 rods/cranks and it will not only handle more h.p,also more rpm. My thinking is build and balance the hell out of it to take far more than you will ever need.
 
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