How strong is stock Mopar vs Csb?

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J

Jim Holmgren

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Hi
I am new at Mopar and wonder how much power for example a 318 will hold up to.

Is the 318/5.2 magnum stronger then the LA 318?

I was going to build a 500-600 hp when I read that original blocks do not hold up to on much more, but I wonder if this is really true as it seems a bit low:burnout:.

It seems had to find cheap Mopar aftermarket blocks.
What is weakest after the block? The connecting rods? how strong are those then?


I have seen a stock Chevy 350 in a C4 corvette here in Sweden that had around 900hp on stock short block from 1984.


What is needed to make a 318 handle 1500hp? Is it even possible with a sensible budget?
 
I might be wrong but all the 350same have four bolt mains, where all small block mopars had a 2 bolt main unless you get a 340 x block which had 4 bolt mains. But a member here was shooting for 1500 on a two bolt set up just on a 360. He had the block line honed on the crank maybe even the cam so everything was true, stud the mains, heads and for that power need forced induction either turbo or turbos or supercharger. Forged crank, rod, and pistons, good flowing heads aftermarket (indy or edelbrock). Turbos are easier on the rotating assembly since it's a gradual increase of power. Have to modify the oiling system there's a good thread on that. Course first of all have the block sonic tested and magnafluxed just to make sure the block is in good shape.
 
What is needed to make a 318 handle 1500hp? Is it even possible with a sensible budget?
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LOTS of money..will it hold together NOT for long..
 
Stock Chevy parts are not as strong as Mopar. 900 HP stock 84 SBC short block is a hand grenade. They would barely make it 70k in a car, Then everything would need to be replaced.
 
It was a 2 bolt block in that corvette.
However it hard forged piston stock, but in the end it throw a connection rod and it took with him the whole bottom part.

It did 765hp and 977foot-pounds with a much smaller turbocharger and did 10.862/134mph at 1/4mile.
But he did not dyno it after the changers he did to it, but he said it did very least 800+hp


Yes I have read that it is not enough material for 4 bolts mains in Mopar sb and there also is prone to main cap walk.
 
But the block is quite strong on the Mopar sb if I understand it right?

With studs in the bottom and maybe a main cap girdle would help it to hold up to 600-700hp?
The heads is fastened with 4 bolts per cylinder, will this be a problem?

My goal is +-600hp for the moment.
 
SBF's split in half at 600, ask Pinks. If you are going to invest in a 600 HP small block, Id go magnum simply for the roller cam, serpentine and the cast pan. Maybe some used "P" Craftsman truck series heads. If any boost after that, "R" block...Thats the price you pay for building a Mopar.
 
66fs said:
Stock Chevy parts are not as strong as Mopar.
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Says who..LS motors come with 6-bolt mains can handle just about anything powerwise..I wouldn't push a stock mopar block past 600 without worrying about it..
 
Is R-block the same as X-block?
Is those blocks still in production, if so where can I find one?

I will be going white stock block for now to get the setup right and then I can invest in a good short block, but it is good to know what is available.

Btw is there any good books about Mopar engines in racing applications out there?
 
66fs said:
We were talking about a 1984 SBC. I have 0 interest in an LS motor.
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Yes it was an 1 gen Chevy sb.
I personally don't like LS engines, they seems to end up more expensive than a 1 gen sbc and are full of electronics, for the quarter mile the old sbc and bbc always seems like a more competitive alternative then LS.
 
It all depends on how you reach that goal. Boosted by anything on the crank, it won't last long. Nitrous, it won't last long. Turbo, it will last a while as long as the tune is on. Naturally aspirated the ceiling for most commonly available race-type small block heads is 650-700. The issue with the blocks is main structure, and cylinder wall integrity. If you plan to exceed the 600hp, it's just stupid not to upgrade the block. Some guys have done it and they last. I suppose that should mean everyone should last. But that's not reality.
 
moper said:
It all depends on how you reach that goal. Boosted by anything on the crank, it won't last long. Nitrous, it won't last long. Turbo, it will last a while as long as the tune is on. Naturally aspirated the ceiling for most commonly available race-type small block heads is 650-700. The issue with the blocks is main structure, and cylinder wall integrity. If you plan to exceed the 600hp, it's just stupid not to upgrade the block. Some guys have done it and they last. I suppose that should mean everyone should last. But that's not reality.
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This sounds about right. Didn't they cast the X and later the R blocks for Pro Stock around 700 HP?
 
Those blocks had the material for real 4-bolt caps and very thick bores as compared to any factory block. The limitation at that point becomes the ability to actually make the horsepower levels that would stress the block to breakage. There simply are not heads good enough to make a lot more horsepower on a 59° block. Ask yourself why the stroker LA and magnum based engines are all pretty much stuck between 600-700hp regardless of the head package or camshaft. You can get more going with special pistons, ring packages, compression, dry sumps, etc. but it really takes the 48° block and head packages to get beyond that airflow ceiling.
 
Most important is how it's tuned. Pushing an LS beyond 600hp is a ripe environment for failure if the tune's not dead on, no different with a MoPar engine or any other really. And as much as I've heard about even the 5.0s having trouble holding power over 500 with stock blocks I've known first-hand accounts of them holding closer to 800 for frankly a healthy few seasons.

That whole 500hp stock crank limit thing was from when it used to be so high stress to actually get to 500hp. The motors had to turn well over 6k and on a cast crank that was asking a lot and seeing a lot of stress. The stress of a naturally aspirated build is harder on it than boost though the tune still needs to be excellent to prevent failure. And as mentioned- really N/A there's not uch easy to get to over 700hp on the stock block. It would obviously take boost to get to 1500- that'd be a lot since a high flowing large inch small block wouldn't likely be much more than 500hp N/A in form setup for high boost. Weak link is not likely the block, everything else should be weaker and more of a restriction.
 
moper said:
Those blocks had the material for real 4-bolt caps and very thick bores as compared to any factory block. The limitation at that point becomes the ability to actually make the horsepower levels that would stress the block to breakage. There simply are not heads good enough to make a lot more horsepower on a 59° block. Ask yourself why the stroker LA and magnum based engines are all pretty much stuck between 600-700hp regardless of the head package or camshaft. You can get more going with special pistons, ring packages, compression, dry sumps, etc. but it really takes the 48° block and head packages to get beyond that airflow ceiling.
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I was talking about Bob Glidden in Pro Stock and stock block limitations. No knowledge, just impressions.
 
stroked340 said:
I'sn't a LS a SMALL block???...
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Yes, just as the newer Hemis are SBs and the mod motors and poly engines are small blocks. But that seems confusing and it's not usually taken into account since all the newer model engines while being short like a small block do not have the same low profile dimensions that the older small blocks have. Many of the smaller cars and unibody Jeeps cannot fit the newer motors in them without significant clearance work while they can fit older small blocks readily.
 
stock gen3 hemi block will take 1500hp. start with that and save the trouble of finding heads for an la engine that do t touch the stock gen3 truck head eagles.
add a stock 6.1 crank good rods and pistons and main n head studs. you got my engine pretty much and im after 1500hp with a turbo. ill be running this summer i hope.
 
66fs said:
Stock Chevy parts are not as strong as Mopar. 900 HP stock 84 SBC short block is a hand grenade. They would barely make it 70k in a car, Then everything would need to be replaced.
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And that is why I went from Chevy to Mopar years ago. Great move indeed..
 
Course there's always a ritter block instead of r3, i order one in cast iron for my turbo build, he also offers aluminum blocks as well.
 
the gen 3 hemi is the hot setup, look at enginemasters the last few years. the old blocks are pretty strong with some block fill cement. let us know when U get that Ritter block matt
 
Will do, being casted now to what I want. Kents a cool guy to talk to. Will post up pics on my build thread. Good price too comparable to the r3 blocks
 
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