Big Block Hp Capability

-
440dartsport

440dartsport

Well-Known Member
Joined
Oct 14, 2010
Messages
607
Reaction score
145
Location
Kewaskum, WI
I just read what the small blocks can take for power and abuse. Now lets hear about what guys are running there big blocks to. I've always heard about 700 hp for RB and 800 for B motors. So lets hear some stories and see pictures of high powered BB's. Good and Bad welcome.
 
z
440dartsport said:
I just read what the small blocks can take for power and abuse. Now lets hear about what guys are running there big blocks to. I've always heard about 700 hp for RB and 800 for B motors. So lets hear some stories and see pictures of high powered BB's. Good and Bad welcome.
Click to expand...
from what ive researched over last couple years due to building a 68 440 a factory forged crank and block are good to about 800 hp and thats pressing it
 
I think its about how much money you have to spend.I would say they could be biult to as much as any thing els....lord knows the parts are out there now.like those big chif heads wow...........Artie
 
Like the small blocks - eventually the prep of a factory block begins to cost closer to a better block. If someone asked me to plan for a real 700hp big block, the first item on the list is a block. Probably from Kieth Black.
 
Does anyone have any experience with a BB coming apart or splitting? I always here guys saying this or that hp limit but I have never seen one come apart yet.
 
440dartsport said:
Does anyone have any experience with a BB coming apart or splitting? I always here guys saying this or that hp limit but I have never seen one come apart yet.
Click to expand...



Yup I've seen a few "windowed" BB's (one of them was mine)but those were in the early days of Nitrous and the lungers were getting pounded good, lots of broke pistons too but we learned. Parts availability to the general Joe and the quality today no problem for a 700HP BB or Stroked B to drive the streets then throw on the slicks uncork the Y and go racing. Above 800 what Moper said.
 
i thought he was asking about a factory block, the aftermarket blocks are much stronger and expensive if realy want to make some hp the all aluminum 572 hemi block is the way to go indy has the predator making 1200 hp for 42.000 or nelson racing engines starting at 28,000 for 800 hp then add his twin turbo applications up to 2200 hp price is way up there. us everyday joes can only dream of these motors or hit the powerball.
 
We're talking naturally aspirated or blown - not turbos and sorry for the wordiness...
The biggest problems I know of are the bores and the main webbing. The bores are not cast well (same as small blocks - core shift) and the bore centers are too close. When you're talking about heads that flow enough to make these power levels you begin to have issues because you can't fit enough intake valve in them. Also if the bore walls are inconsistent the ring seal can begin to go away and ring seal is huge if youwant to make these power levels. Some of that can be fixed with filling, but that doesn't work well if you need to drive the car (idle time, etc) because you can't fill up where the ring seal is most crutial unless it's a race only deal.
The main webbing, even in the early '71 "230" 400 blocks is not really good for these power levels. You can girdle them, and use better caps, and cross bolt - and the bottom will still eventually fall apart and cracks will appear in the main saddles. This is why I am against girdles and billet steel caps on big blocks. All they do is transmit the harmonics to the block better. The best way to keep a block alive is accept that at some performance level you need a better one. I would rather have a customer spend $5K on a completely machined KB aluminum block that will survive anything we can toss at it than spend $3500+ on a factory block, getting completely tested and machined, fit with a girdle, modified oiling, and lifter bore bushings. That $1500 difference pays for big weight reduction, safety, expandability, reliability, and rebuildability. If the engine buget is $16-18K we're talking about 9% to upgrade the block to "never need another one".
In terms of carnage -
Block #1 - 440: my ported 915s, MP .528, KB hypers, LY rods. It ran 11.60s in a B body with 4.10s and he drove it to the track (1.5hrs on the highway) and it had over 500 logbook passes down the track. The crank let go in the burnout box at 3500rpm and it scattered. The webbing had cracks that were ovisouly older (carbon/oil residue in them)
that had opened up and it blew.
Block #2 - 70's 440: had been run with the MP 509 cam and not much else but bolt ons. Made about 430hp. Lived that way for years of street abuse and never showed signs of problems. Upon disassembly for rebuild and stroking - the saddles had cracks in them and the caps were walking around.
Block #3 - Another friend - call him more of a mentor really - he had an 875hp RB 496 wedge explode on it's first pass after being flogged on the dyno. It took the right front tire off and put the car into the wall. This is not typical but when you're responsible for building something this potent I ask myself is the risk worth it? Again - these are not 12 second cars. Someone can be killed by a decision of going cheap and I take that seriously.
 
bOb shingler said:
what do you think causes the main webbing to crack? i'm thinking a less then perfect balance job. any one have any thoughts on this.
Click to expand...
I have seen the blocks start cracking in the main saddles with 14to1 comp.without the girdle at 7000.after being drilled for the hemi 4 bolt caps no trouble............Artie
 
I have heard that girdles dont help if the caps are not made to interlock with the girdle. IMO if you are going to build anything over 750HP NA let your engine builder deside on your block.
 
bOb shingler said:
what do you think causes the main webbing to crack? i'm thinking a less then perfect balance job. any one have any thoughts on this.
Click to expand...


My own feelings are
1. It's a combination of casting design and balance job (which many for some reason think they'll "feel" if it's "bad") or a combination of those two and a cheap harmonic dampener.
2. Detonation. It's detonation that makes the caps walk and you can find that on a factory stock engine. You can't always hear it, but the block will always feel it.
The most I'll invest into a factory block is aluminum caps and main studs. Those two, with a properly balanced assembly, and a good dampener will withstand a lot of abuse at the 600+ hp range and doesn't break the bank to do. The caps absorb the shock loads rather than transfer it to the webbing and the studs keep them basically where they need to be. Aluminum rods and a belt drive are also great tools to help the block live.
 
mancini racing has a siamese-bore 440 iron block for $3,000 might handle 1,000 hp not sure I have 68 440 e dated augest 1968 one of the first ones with srenghting rib aroung thr freeze plugs found it in local trade paper was sitting in a horse barn guy wanted $600.00 for block and crank offered him $500.00 loaded it the truck and off i went have seen 76 and 77 blocks as low as $75.00 bucks. The more you spend the more you get but find a good engine builder knowledge is priceless.
 
I have looked at different year 440 blocks and I prefer the 75 and newer blocks. They are thicker between the crank and cam and also have the ribs on the outside of the block. They have bigger water ports in the deck and also have thicker mounting ears. I don't know about the nickel content between the years but I think the newer blocks are stronger mostly because of the extra meat between the crank and cam journals.
 
its a common ploy to talk down about the later year RB's, so that they can be picked up cheaper.

Everyone knows a 240' casting 1972 400 is the holy grail of bigblocks because of the "Main Webbing".......so its easy to talk smack about all the other years' castings because they are not as "beefy", so they are "weaker"/worthless. A Block is a Block, heads are heads, cranks are cranks,......it is the machine work and the combination of parts that make or break an engine.

Just because a person who owns a Machine Shop exists, doesnt make them the Best in the world.

And a properly prepped Bigblock can EASILY go over 1000hp...
[ame="http://youtu.be/Bz0vuCmzFEs"]302 Found[/ame]
 
Im by no means and expert but i thought i read somewhere that a super or turbo charged engine "cushioned" the hit on the crank thus helping with cap walk and stain on the upper webs. Is that true?
 
Prine said:
its a common ploy to talk down about the later year RB's, so that they can be picked up cheaper.

Everyone knows a 240' casting 1972 400 is the holy grail of bigblocks because of the "Main Webbing".......so its easy to talk smack about all the other years' castings because they are not as "beefy", so they are "weaker"/worthless. A Block is a Block, heads are heads, cranks are cranks,......it is the machine work and the combination of parts that make or break an engine.

Just because a person who owns a Machine Shop exists, doesnt make them the Best in the world.

And a properly prepped Bigblock can EASILY go over 1000hp...
302 Found
Click to expand...

lol... It's the 230 block, and it's only the ones that were cast in early'71. After about June of '71 there is nothing special and with the bore core shift some are useless for big power anyway.
In regard to the "1000hp" comment - re-read the top of my post #11. Turbos don't count...lol. A turbo application can go way beyond as long as they don't detonate. That's because the turbo oesn't take power or stress the crank in any odd way. A blower does. Some blowers do a lot... So the risk is lowest building a turbo.
 
Koleno block $3995 from Hughs and as the add states "not ready for assembly"
So another $1000-1200.

This block let go last race of the season at Woodburn Or.
Didn't even Qualify for the event.

Rod bolt.
ResizedImage_1347211703394.jpg


Even after market blocks and and parts have there limits.
 
I just had mine bored .055" over. Some of the later blocks were the thickest ones. I'm planning on making 700hp with this new motor. Time will tell, it's going on the Dyno in less than a month.
 
womanator said:
Koleno block $3995 from Hughs and as the add states "not ready for assembly"
So another $1000-1200.

This block let go last race of the season at Woodburn Or.
Didn't even Qualify for the event.

Rod bolt.
ResizedImage_1347211703394.jpg


Even after market blocks and and parts have there limits.
Click to expand...

that motor looks like it's supercharged. it also looks like it's welded together or is it just the way it's cast.
 
You must log in or register to reply here.
-

Back
Top