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Re: ok 9 sec rb
[Re: earthmover]
#1023839
07/02/11 09:59 AM
07/02/11 09:59 AM
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Joined: Jan 2003
Posts: 9,996
Frostbitefalls MN (Rocky&Bullw...
gregsdart
master
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master
Joined: Jan 2003
Posts: 9,996
Frostbitefalls MN (Rocky&Bullw...
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Quote:
My 499 combo with large port heads, flowing about 310 unported went 9.30s at 3000 lbs. 12.5/1 compression, Methanol for fuel. Shifted it at 6800. You should be able to run the same shift points, and the 4.88 might be a touch on the high side. With rollout of 103, 6 percent slip, I come up with 7400 rpm through the traps at 140 mph. 7200 at 136 mph. So it should be real close on the gear, might need to drop to a 4.56 or 4.30. Ask your engine builder how many rpms he wants to see in the lights. If you have room, there are some slicks out there that go 106 roll out, would put you into a situation where you have lots of fresh tire, no gear change to do. A tire that will grow some in the lights like those with the 106 roll out will bring you down to 7100 rpm at 140, with 6 percent slip.
is this a stock block or race block combo????? its a bad azz running combo... thanks 
Stock 400 block. I had to sleeve a cylinder after the first few passes, one split. Cost me a weekend, plus sleeving,gaskets, rehone, and rings. About $500. Was OK after that, still running in Texas.
8..603 156 mph best, 2905 lbs 549, indy 572-13, alky
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Re: ok 9 sec rb
[Re: Performance Only]
#1023840
07/02/11 10:42 AM
07/02/11 10:42 AM
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Joined: Feb 2005
Posts: 846
Long Island, NY
Cudafied
super stock
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super stock
Joined: Feb 2005
Posts: 846
Long Island, NY
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Quote:
personally i know 750 HP RB's aren't really time bombs like some people think if built and tuned properly. aluminum caps and studs, fairly light components, precision balancing etc. etc.
we've got plenty of them making that much HP and more for many years without any problems.
we typically freshen them every couple of years. use "good" quality parts, including the harmonic damper.
i've seen a number of broken blocks over the years and in almost every case the owners were E.T. chasers. constantly chasing the tune up to try and squezze every last 1/2 hp out of them but in the process caused way more harm than good getting into overly lean or rich carb conditions and detonation. that's very often the killer on those type combos IMO.
proper machine work, proper attention to assembly, clearances etc, good parts and a good tune or the keys to longevity for any engine, but even more so when you have a block that might otherwise be near the edge in the HP catagory.
Hey thanks for the insult 
Are you kidding with the blanket assumptions your making 
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Re: ok 9 sec rb
[Re: Cudafied]
#1023841
07/02/11 03:13 PM
07/02/11 03:13 PM
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Joined: Jul 2010
Posts: 2,091
Delray beach, Florida
Performance Only
top fuel
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top fuel
Joined: Jul 2010
Posts: 2,091
Delray beach, Florida
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Quote:
Quote:
personally i know 750 HP RB's aren't really time bombs like some people think if built and tuned properly. aluminum caps and studs, fairly light components, precision balancing etc. etc.
we've got plenty of them making that much HP and more for many years without any problems.
we typically freshen them every couple of years. use "good" quality parts, including the harmonic damper.
i've seen a number of broken blocks over the years and in almost every case the owners were E.T. chasers. constantly chasing the tune up to try and squezze every last 1/2 hp out of them but in the process caused way more harm than good getting into overly lean or rich carb conditions and detonation. that's very often the killer on those type combos IMO.
proper machine work, proper attention to assembly, clearances etc, good parts and a good tune or the keys to longevity for any engine, but even more so when you have a block that might otherwise be near the edge in the HP catagory.
Hey thanks for the insult
Are you kidding with the blanket assumptions your making
i wish i knew what made you feel "insulted" and what "blanket assumptions" your talking about.
you cracked a block, so have others. do you fall into the e.t. chaser crowd? who did the fill? was it done properly with a torque plate installed and the proper mix of grout and water? was the block even sonic checked prior to all of the work starting on it. look, maybe you did everything you thought was right and maybe you didn't, who knows, but all i can tell you is my own experiences from over 30 years of building these things. if your seriously taking my comments as blanket statements and insulting, it wasn't meant that way, but i do call em like i see em. i'm not one to try to be "soft spoken" or "politically correct" so know one gets their feelings hurt. 
Last edited by Performance Only; 07/02/11 03:24 PM.
machine shop owner and engine builder
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Re: ok 9 sec rb
[Re: Performance Only]
#1023842
07/03/11 10:12 AM
07/03/11 10:12 AM
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Joined: Feb 2005
Posts: 846
Long Island, NY
Cudafied
super stock
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super stock
Joined: Feb 2005
Posts: 846
Long Island, NY
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Quote:
Quote:
Quote:
personally i know 750 HP RB's aren't really time bombs like some people think if built and tuned properly. aluminum caps and studs, fairly light components, precision balancing etc. etc.
we've got plenty of them making that much HP and more for many years without any problems.
we typically freshen them every couple of years. use "good" quality parts, including the harmonic damper.
i've seen a number of broken blocks over the years and in almost every case the owners were E.T. chasers. constantly chasing the tune up to try and squezze every last 1/2 hp out of them but in the process caused way more harm than good getting into overly lean or rich carb conditions and detonation. that's very often the killer on those type combos IMO.
proper machine work, proper attention to assembly, clearances etc, good parts and a good tune or the keys to longevity for any engine, but even more so when you have a block that might otherwise be near the edge in the HP catagory.
Hey thanks for the insult
Are you kidding with the blanket assumptions your making
i wish i knew what made you feel "insulted" and what "blanket assumptions" your talking about.
you cracked a block, so have others. do you fall into the e.t. chaser crowd? who did the fill? was it done properly with a torque plate installed and the proper mix of grout and water? was the block even sonic checked prior to all of the work starting on it. look, maybe you did everything you thought was right and maybe you didn't, who knows, but all i can tell you is my own experiences from over 30 years of building these things. if your seriously taking my comments as blanket statements and insulting, it wasn't meant that way, but i do call em like i see em. i'm not one to try to be "soft spoken" or "politically correct" so know one gets their feelings hurt.
My feeling are not hurt and I don't want to get into a pi$$ing contest 
The insult was to my Intelligence by making it sound like it is someones fault that a 40+ year old engine block decided to let go after years or use, Mechanical failure is not predictable. When you get to the end of the life cycle of an old part it usually does not end well. And the fact that you as a respectable macine shop would let someone build an engine at that power level with - and I quote Quote:
when you have a block that might otherwise be near the edge in the HP catagory
instead of using a better block.
Assumptions:
The assumtion of not using good quality parts - balancer included, The assumtion that being an ET chaser is the only reason for this type of failure (as bracket racer the most important things are reliability and consistency not squeezing an extra 1/2 hp), The assumtion that proper machine work was not performed and fanatical attention to detail was not used in assembly and tuning, the assumtion that no one on the planet can build an RB properly. 
As a longtime Mopar racer I raced through the years when you had to use all old parts and hope they would last. Now we have lots of choices from the aftermarket manufacturers why not build with all fresh components when older parts have questionable life expectancy? 
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