tom123payne

This may have been touched on before. Who has actually made enough horsepower on a stock iron block and had problems with the blocks structural integrity? Im ordering parts for my build now and everything i have read is saying dont push your luck on the stock block. "Buy an lsx, dart,erl ect." Just curious what would actually fail and cause problems. Im looking at building a 408 with alot of boost. But if i buy an aftermarket block the build may change. looking for 1200 to the tire with room to turn it up. TIA

LLLosingit

iTrader: (4)

Not necessarily a block problem but I have a 408 that I'm getting billet main caps and getting them pinned because it showed signs of cap walk, It's running Callies crank and rods. This is a roots blown application so that may have contributed to the problem.

I see more problems with people lifting heads under high boost so a 6-bolt block/heads helps there.

1200 to the tire is asking a lot from the stock block and wanting to turn it up from there you'll be better off buying a better block.
If it's strip use only you could just fill the block and might get you what you want.

Another reason to go aftermarket is they have deeper/longer bore/sleeves, The stock block with 4" stroke pulls the pistons down past the bottom of the bore quite a bit and tends to be hard on the piston skirts.

tom123payne

What kind of power are you making to cause the main caps to walk?

LLLosingit

iTrader: (4)

900+ but like I said it's roots blown so there is force being applied to the snout that a N/A or turbo combo doesn't see.

07NBSChevy

iTrader: (1)

I have seem stock Iron Blocks handle 1,000 crank HP with ARP Mains. I would honestly not push it more than that running high boost.

But 1200 to the tire is a lot. That is around 1400-1500 crank HP and I would not risk that, especially investing all that money to achieve said HP to only skimp on the block. I would go with the LSX Tall Deck Block.

tom123payne

Ahh..I see. This cant be the only reason that people step up to these high dollar blocks. I have found all kinds of solutions to your problem such as what you intend on doing with billet main caps, Doweling the caps and also i have found girdles for the caps. if this is the only reason that i can come up with I cant justify the money on a race block.

tom123payne

I can agree to an extent... But what could happen? What has happened? Does the block crack under pressure? Does it just come apart? has anybody actually seen one fail because of too much power? I can understand logical thinking, $4000 dollar rotating assembly in a $500 block doesnt seem like good sense. but why?

LLLosingit

iTrader: (4)

What is your budget? If you're not in the 8-12k range you might want to lower your expectations by a few hundred reliable HP.

There are many examples of problems with the stock blocks but not issues I've experienced myself other than my post above. The simple fact is the stock block just isn't cut out for that kind of power, Like I said earlier, issues at that power level on stock block, Main cap walk/heads not sealing under boost/piston pulling out of bore on a 4" stroke. those problems are less likely with an aftermarket block, I don't know what your budget is but I know what I have in my build and all things considered if did it over again I would spend the money on the block, If you can afford the parts needed to build a dependable 1200rwhp then it's not that much more added to your budget.

LLLosingit

iTrader: (4)

Quick run down on my costs not including block or machine work. $1700 crankshaft/$900 rods/$900 pistons and rings/ $700 cam kit/$3300 Heads That's $7500 and doesn't include the block/machine work/bearings/gaskets/oil pump/timing set/rockers and all the little things needed to make it a long block. Then I have a 3k Holley EFI, $7,000 blower/manifold/injector plate/injectors/coils. Fuel sytem to support that kind of power is likely 1k and so on. If I went turbo I would expect to be safely in the 12,00-1400hp range but not sure how reliable it's going to be. Also keep in mind the a trans that holds that kind of power is around 4-5k and then your weak link is the driveshaft and rear so add another 3-5k
Yes I know it can be done cheaper but cheap and reliable rarely go together.

tom123payne

Your pretty close to where i will be at on this build as far as money spent. The supporting mods to the truck are for the most part already there, Rossler th400, Fab9 rear end, custom drive shaft. I will be going to an aftermarket engine management system but im focused on the engine build at this time. I most likely will go with an aftermarket block. I will have to research them all to see which one will suit me the best. When i set out for the engine build i fully intended to spend 10k easy, just didnt budget for the block. I will have to budget a little harder to try and squeeze that in.

07NBSChevy

iTrader: (1)

I have seen a stock block pushing 900hp crack the block right at the side bolts for the mains. Now, was it because of block failure or something else, I cant say for sure. That is why LSX blocks sr8e reinforced around the mains, use 6 bolt style heads, more material around bottom of cylinders and so on. I cant remember off the top of my head but LSX blocks may use oil squirters as well.

pantera_efi

iTrader: (1)

Your needs may be better met with a RHS 356 block with included Billet Main Caps.

Lance

JoeNova

Increasing stroke makes the problems associated with the stock block worse. You end up with more stress on the mains and the sleeves. This is why you see guys having issues at ~1000 HP with an iron 408 but there are half a dozen stock aluminum 5.3 blocks in the 1400 HP range (some of those with stock rotating assemblies).

KCS

iTrader: (20)

Depends on the block. The 6.0L iron blocks will usually split between cylinders or the heads will lift and hydrolock a cylinder or two.

The aftermarket iron blocks are made of a stronger iron and have siamesed bores to keep the cylinders from failing. The extra bolt holes on the aftermarket blocks also help keep the heads from lifting.

brngrhd

Stock iron 6.0 block, 4 bolt heads, nothing fancy ARP hardware......

https://www.streetmachine.com.au/str...ns-7-37-186mph

NAVYBLUE210

The stock 6.0 Iron block is much more durable with 3.622" Crank
and turbos Vs 4.00" crank and blower. Budget 6.0 Iron block
Probably work with stock crank as well, upgrade rods and pistons.
I used the LSX Iron Block for my NA build overkill perhaps
But I wanted the benefits of priority main oiling as well.
Oil squirters do not come with the LSX Block my builder added
Them. The LSX & Dart Iron Blocks are about $2500.00,
Dart & Callies Aluminum about double that!

A.R. Shale Targa

iTrader: (2)

THIS RIGHT HERE MAKES IT A NO BRAINER
you simply will find ALL the weak links of a block designed for 400 horse when trying to make 1400 or more