**600hp sbm block limit? Or is it bs!!**

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Mad Dart

Mad Dart

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Ok, all have heard all this "talk" that a SBM Block has a limit of 600HP before it Grenades, as far as I know it is all BS. I am not saying the it is not true but would like some actual proof from an end user.

Post your Broken Block Pictures along with a Story as to How it actually did Fail or Break and at What Power Level.
 
Got a feeling that this is in the same arena as the "Ebay turbos are junk" line.....
 
inkjunkie said:
Got a feeling that this is in the same arena as the "Ebay turbos are junk" line.....
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Possibly, all of us have heard this for a long time now. There are so many Small Block Mopar end users on this site that there has to be at least a handful that have grenade'd their blocks and have some proof. I have done my own research and have found absolutely "None"!

I have also heard of Cap Walk and Cylinders moving around at higher power levels........... Time to prove it to all of us here. I am sure that I am not the only one that wants to see the 1st hand evidence!
 
inkjunkie said:
You are not getting nervous..........are you???
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Hell no I am not getting nervous!, gunna prove everyone wrong! or I will find out first hand and then it will not be BS anymore! haaaa

Usually if something else fails, it will take out the block "Dropped Valve, Broken Rod, Piston Pin or whatever". So my thinking is at higher power levels other parts may fail, taking out the block giving it a bad rap!
 
Well i got no pics, but if your looking for more than 600hp i know that using mounts on the block will show the walls are effected by using a mount...same holds true for the bb's
So you want to use ears when you get beyond 450hp...
Are you using a la or mag.... i wouldn't trust a mag block
 
Supershafts said:
Well i got no pics, but if your looking for more than 600hp i know that using mounts on the block will show the walls are effected by using a mount...same holds true for the bb's
So you want to use ears when you get beyond 450hp...
Are you using a la or mag.... i wouldn't trust a mag block
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I am using a 1973 LA Block on mine.
 
Well Louis I,m sure you,ve seen my(77 360LA) block:banghead:due to driver error.Do you have a girdle on your TT build?What year is your block?I,ve heard of main caps breaking and also cam valleys breaking,but never seen real pics(just talk).Here,s a pic of mine after"hydraulicing" just to get the pics rolling.
Oh,its a stroker 410,running roughly around 525hp(10.64@123mph)
View attachment 66 Dart project Nov2010 385.jpg

View attachment 66 Dart project Nov2010 396.jpg
View attachment 66 Dart project Nov2010 394.jpg
 
pettybludart said:
Well Louis I,m sure you,ve seen my(77 360LA) block:banghead:due to driver error.Do you have a girdle on your TT build?What year is your block?I,ve heard of main caps breaking and also cam valleys breaking,but never seen real pics(just talk).Here,s a pic of mine after"hydraulicing" just to get the pics rolling.
Oh,its a stroker 410,running roughly around 525hp(10.64@123mph)
View attachment 275918

View attachment 275919
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Perfect, that is what I am looking for, REAL life happenings. So did yours Hydraulic after loosing a Head Gasket? Tell more details please.

I am not worried about my build at all, I did not post this thread because I am worried. The only thing I am worried about is people saying My cousins brothers uncles Nephews girl friends dad blew up his SBM and it had 600HP.

The reason I posted this thread up is you HEAR of blocks breaking in all these threads. People tend to repeat things even if they are not true.
 
I would like to hear more "Main Cap Walk" horror stories with these 4 inch Stroker SB's. There's some pretty fuckin tall tales out there, with little realistic (or convincing) proof, that these Stroker's aren't reliable enough to drive daily.
 
YoungBlood said:
I would like to hear more "Main Cap Walk" horror stories with these 4 inch Stroker SB's. There's some pretty fuckin tall tales out there, with little realistic (or convincing) proof, that these Stroker's aren't reliable enough to drive daily.
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Exactly, alot of "talk" even from the "Heavy Hitters" on this site claiming that a Small Block Mopar is Done at 600HP, has cylinder wall movement and cap walk when using a stroker like it should be used which is "driven".
 
I had a 1970 340 block that I raced and it eventually made 602 HP on the dyno. I ran it for several years until the main webbing literally split the block in half! It had 4 bolt mains installed and all the other tricks done to it but it just could not handle that power run after run. It did run 9.50s @ 138 MPH shifting at 7900 rpm. 3.58 stroke crank in it. Naturally aspirated. I had a lot of passes on it over the years and refreshed it every year at the end of the season. It started out with W-2 heads and then W-5 heads which made way more power and it only lasted for 40 runs when I went that route making 602 HP. I have since went to an R3 block W-9 heads and have never looked back.
 
I think a stud girdle would increase how far you could push it. Once I get the cage and stuff in mine, I plan on juicing it with a 100 or 150 shot, which will push it well above 600HP. I only spin mine a little past 6K.
 
pink340swinger said:
I had a 1970 340 block that I raced and it eventually made 602 HP on the dyno. I ran it for several years until the main webbing literally split the block in half! It had 4 bolt mains installed and all the other tricks done to it but it just could not handle that power run after run. It did run 9.50s @ 138 MPH shifting at 7900 rpm. 3.58 stroke crank in it. Naturally aspirated. I had a lot of passes on it over the years and refreshed it every year at the end of the season. It started out with W-2 heads and then W-5 heads which made way more power and it only lasted for 40 runs when I went that route making 602 HP. I have since went to an R3 block W-9 heads and have never looked back.
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Thanks for your post.
There is alot of speculation that adding the 4 Bolt mains actually weaken's the webbing in the block. In your situation that may have been the case and I would think that is why it failed, but still that is only speculation.

Was there fatigue that you physically noticed or catastrophic engine failure from the cracking? or did you notice it when you took it apart?

And man you were revving the bageebers out of that engine! Damn
 
64physhy said:
I think a stud girdle would increase how far you could push it. Once I get the cage and stuff in mine, I plan on juicing it with a 100 or 150 shot, which will push it well above 600HP. I only spin mine a little past 6K.
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I don't know about the girdle. The one Hughes sells will not do much because the contact at the top of the Main Caps is Minimal, even when doing there secondary method of machining the top of the stock caps instead of using their spacers. There is someone on here that makes a really good Girdle with matching machined aftermarket caps that contact the girdle all the way across the caps.

Yes you will be well over 600HP when you Juice that engine!
 
Louis I had went to the track 3 weeks ago.I unload the car and it was running rough,so I thought it was due to the cold weather(was 12*)outside.When I checked the carb,the rear float was stuck,shut car off tap carb,restart alls good.Well I,m thinking when I shut it off,the gas ran into the cylinder and when I fired it up it pushed the cyl down on a up stroke,causing it to hydraulic and bend a rod.This is all I can think of as I,ve changed oil regularly and it,s been running like a top.:wack:
 
YoungBlood said:
I would like to hear more "Main Cap Walk" horror stories with these 4 inch Stroker SB's. There's some pretty fuckin tall tales out there, with little realistic (or convincing) proof, that these Stroker's aren't reliable enough to drive daily.
Click to expand...

Mad Dart said:
Exactly, alot of "talk" even from the "Heavy Hitters" on this site claiming that a Small Block Mopar is Done at 600HP, has cylinder wall movement and cap walk when using a stroker like it should be used which is "driven".
Click to expand...


Oh wait.....

Having 600hp and DRIVING it.

That's different than having 600hp and USING it at 600hp. . .



pink340swinger said:
I had a 1970 340 block that I raced and it eventually made 602 HP on the dyno. I ran it for several years until the main webbing literally split the block in half! It had 4 bolt mains installed and all the other tricks done to it but it just could not handle that power run after run. It did run 9.50s @ 138 MPH shifting at 7900 rpm. 3.58 stroke crank in it. Naturally aspirated. I had a lot of passes on it over the years and refreshed it every year at the end of the season. It started out with W-2 heads and then W-5 heads which made way more power and it only lasted for 40 runs when I went that route making 602 HP. I have since went to an R3 block W-9 heads and have never looked back.
Click to expand...


Never had a lower end issue, however using mounts did show a issue..

More issues with keeping the heads on, using studs tq'in them higher, that was also the reason to move to the r block.

However on your 4 bolt did you use a splayed 4 blt with the center studs or did you use the 4 studs.
 
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