When will it explode?

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mopar_stroker

mopar_stroker

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Husqvarna, Sweden
I have built a -73 440" based 505" stroker. Half filled with hardblock, BCR alu maincaps and a BCR girdle. Bore is 4.350". Magnafluxed, sonic checked. Flattop KB pistons, eagle H-beam rods 7.100 and a 4,25 440 source crank. Indy 440-1 heads, jesel shaftmounted rockers 1,7. Will run it on E85. But when will a engine build like this explode? the block are as perfect as it can be. Great cylinder thickness on all cylinders, no cracks. Have searched the internet for answers. some people say 750hp, and some say that they have been running 440 blocks with hardblock and girdles at 1000hp without exploding the block... whats true and whats false?

Best regards a the swede.. 8)
 
Most of the stock blocks are safe up to 600 Hp-700Hp. I would not build one with more HP then that. But, that is from I have learned over the years.
 
Mate in western australia had one at 900hp without ally caps and it only lasted one or two meetings.

Here is a pic of my poor old big block, cracks clearly can be seen each side of oil hole on mains and running down into the bores
Click to expand...

DSCF1868.jpg
 
in MY experience...it will explode immediately after you hear a funny noise that sounds like metal on metal......engines are different that human interaction, with engines ONE TOUCH and the dance is OVER!
 
I've built several engines in the 600-700 HP range with a stock block and have had no problems. But IMO, that is at the limit.
 
Biggest problem with 2 bolt mains in the B-RB blocks is the cap walk which leads to the engine going away.

When I built the engine for my 68 I used the 400 based engine.

Have over 250 runs on the block.
Car runs 9.60's about 750 crank hp

IMGP1124.jpg
 
My machinst told me 650 is about max for a RB no block fill. He said that the 400 with a half block fill and good machine work should be good for about 750.
 
ramcharger said:
My machinst told me 650 is about max for a RB no block fill. He said that the 400 with a half block fill and good machine work should be good for about 750.
Click to expand...
a friend runs a 400 based 505 with B1 heads. it has 863hp, and it has been running without problems the past two seasons. but i suppose the rb block is much weaker.. ](*,)
 
It will probably explode when sumthin breaks. That's just a guess, though.
 
mopar_stroker said:
a friend runs a 400 based 505 with B1 heads. it has 863hp, and it has been running without problems the past two seasons. but i suppose the rb block is much weaker.. ](*,)
Click to expand...

I'm only going by what Dave Caprioti of DC racing told me. I got to trust him since he's been a machinist since the late 70's. More power to your buddy (no pun intended, lol!).
 
low decks are a more solid/rigid block to use at this power level, less room though.

It varies really...
I've seen hemi blocks that were cracked all over-bad casting
same could and can be said for the 440's, a lot of core shift..I had one here that tested way off to one side.


can't say that I've built any 600-900hp 440s though...
 
You know if you have to ask this question, your most likley going to test the limit. It may cost a bit more to get an aftermarket bloc at first, but after it blows apart, youll end up with one anyway.

The good thing is, there are several good Mopar Big Blocks to chose from. Koleno, Indy, World, KB. The small block guys are not so lucky.
 
I ran my 383 stroked to 440ci to 1300hp before i cracked 2 cylinder walls. For 2 years I ran the block with a 88mm turbo making approx 1000hp. Maybe I was lucky but it was a stock block with a girdle and no block hardener:glasses7:
 
MRL Performance said:
You know if you have to ask this question, your most likley going to test the limit. It may cost a bit more to get an aftermarket bloc at first, but after it blows apart, youll end up with one anyway.

The good thing is, there are several good Mopar Big Blocks to chose from. Koleno, Indy, World, KB. The small block guys are not so lucky.
Click to expand...

Us small block guys get lotsa HP with our little blocks.
 
two things might also help it live longer

a good harmonic balancer not a 35 year old one
a rev limiter
 
I pretty much agree with all of the above, but I would add one thing. A main girdle kit, these seem to stop some of the cap walk. We ran a 500+ motor for over 7 years at the drag strip and beat on it constantly going through the traps between 6800 and 7200 RPM. It finally took out the center main web, all the way up into the cam bearings. Needless to say, the next one we built had a main girdle on it and it ran for another 7-8 years before the car would no longer pass certification by NHRA, or IHRA. We scrapped the car and the motor is sitting sealed up with the vavle gear off until we find another car to put it in. And just FYI, no it is not for sale. LOL

Bill S.
 
IMO, the problem is the girdle. The main caps are enough on thier own to take 800+, but the reason they last is they absorb a lot of the shock that the block has to deal with. It's the harmonics that cause the main webbing to fail over time. When you use steel caps, and or a girdle, you transmit ALL the harmonics to the webbing and that will shorten the life. I've had my hands in a 500hp 440s that lasted 8 years, thousands of street miles and hundreds of passes, before the webbing cracked and it grenaded. And it failed at 4500rpm... I've also been involved with a 528 that was just shy of 900hp live well with just aluminum caps. All depends on the tune, the car it's hauling (weight), and the amount off harmonics transmitted to the main webbing.
 
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