70 340 HP handling ability.

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Dmopower

Dmopower

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Hello guys and thanks in advance for the help. I am wanting to build a 340 stroked to 426. I have a good 70 340 block with std bore. I have milodon 4 bolt splayed main kit and a hughes girdle kit. I'll be using a Milodon 7qt oil pan. 234 242 cam. It's a street daily driver.9.5 or 10 to one comp. I'm thinking about adding a torquestorm supercharger down the road and am wondering if my block will hold up to the 700 hp level that this combo could achieve. Any help and insight is greatly appreciated.

Don
 
That's a stretch, you'll need an R block for that kind of horsepower. Also, 9.5/10 CR is too high if you're going to use a super charger. 65'
 
Plymouth 65 said:
That's a stretch, you'll need an R block for that kind of horsepower. Also, 9.5/10 CR is too high if you're going to use a super charger. 65'
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I am looking at the Ritter block down the road for another build. The 9.5 to 10 CR was a guess as I've seen the guys run different overdrive to get the Psi that works for their application. 2 questions. Is 700 hp a stretch for the potential of this build 426 with a torquestorm? What HP max would a 340 to a 426 with Milodon caps and a girdle kit be in your opinions? Thanks again for the help.
 
Most people say the stock block is good for 600hp +/-.

I've also been told that using the outer holes on the four bolt mains is a no-no because the stock block is not thick enough to support the extra bolts. Better to leave them out or cut the ears off
 
gzig5 said:
Most people say the stock block is good for 600hp +/-.

I've also been told that using the outer holes on the four bolt mains is a no-no because the stock block is not thick enough to support the extra bolts. Better to leave them out or cut the ears off
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Does that apply to the splayed main caps also? I thought that was why they offset the outside bolts and angled them to an area that was thicker. Not arguing I just don't want to do this twice and already have the main kit.
 
As stated 600 HP is about it for a stock block. Even with better cap and a girdle. Most street supercharged engines run low to mid 8:1 compression. That way you can run some boost to make horsepower. Lightweight forged pistons and a good set of rods would also be required. 65'
 
Dmopower said:
Does that apply to the splayed main caps also? I thought that was why they offset the outside bolts and angled them to an area that was thicker. Not arguing I just don't want to do this twice and already have the main kit.
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I don't know if the splayed version makes a difference but without looking at it, I would says off hand that if there wasn't enough material for a straight bolt, laying on an angle doesn't fix the problem. My understanding is that these four bolt caps were brought out to replace the two bolt caps on X or R blocks that didn't come with a four bolt version. But they have a solid webb to hold the extra screw, stock blocks don't.
 
Dmopower said:
Does that apply to the splayed main caps also? I thought that was why they offset the outside bolts and angled them to an area that was thicker. Not arguing I just don't want to do this twice and already have the main kit.
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Yes. No matter where you put that outer bolt there isn’t enough material for it. That hole makes the block weaker. Now you stick a bolt in there and load it and it’s even worse.

Every dedicated race block Chrysler made and the Ritter block ALL use straight, 1/2 outer bolts. They did that for a reason. And they made that area of the block much stronger to take that load.
 
The gen 3 hemi platform is where I would go. That block wont be happy at that power level for long, especially by weaking the pan rails with a 4 bolt cap. R3 or ritter if sticking with a SBM in my opinion
 
Plymouth 65 said:
As stated 600 HP is about it for a stock block. Even with better cap and a girdle. Most street supercharged engines run low to mid 8:1 compression. That way you can run some boost to make horsepower. Lightweight forged pistons and a good set of rods would also be required. 65'
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So there is no way to get a 340 to handle the power potential of a Torquestorm plus? I see they advertise that model for 700hp. I was hoping to get in the 500 to 525 range on engine alone. I guess with 8 to 8.5 to 1 my hp would be reduced some. 450 + 40% is 630. A lot of guessing on the math but that puts me right there at th
Rat Bastid said:
Yes. No matter where you put that outer bolt there isn’t enough material for it. That hole makes the block weaker. Now you stick a bolt in there and load it and it’s even worse.

Every dedicated race block Chrysler made and the Ritter block ALL use straight, 1/2 outer bolts. They did that for a reason. And they made that area of the block much stronger to take that load.
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Ok. Would I benefit from having the extra metal cut off the Milodon caps and use them as a HD 2 bolt kit or should I stick with the factory main caps? Then use the girdle? I want to get the 340 the best I can for this build. I can get a Ritter block down the road.
 
Dmopower said:
So there is no way to get a 340 to handle the power potential of a Torquestorm plus? I see they advertise that model for 700hp. I was hoping to get in the 500 to 525 range on engine alone. I guess with 8 to 8.5 to 1 my hp would be reduced some. 450 + 40% is 630. A lot of guessing on the math but that puts me right there at th


Ok. Would I benefit from having the extra metal cut off the Milodon caps and use them as a HD 2 bolt kit or should I stick with the factory main caps? Then use the girdle? I want to get the 340 the best I can for this build. I can get a Ritter block down the road.
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Yes. The Milodon cap is significant better than the factory cap. Cut the ears off and use them.

I’m not big on the girdle either. It just moves the flexing of the block and crank to other places. If the block is moving enough it needs a girdle, you need a better block.
 
700 h/p might not be all that street friendly in a daily driver .
Ever drive anything with big power and no traction ?
 
Again, I'm not the expert but they say that how you make the power, makes a difference. Supposedly a 700HP NA motor is harder on parts than a 700hp turbo motor. Boost is boost as far as I know so probably a belt driven blower is similar to a turbo in that regard. That 600hp guesstimate is for NA power so 700 boosted may be doable on the stock block. If you can afford a Ritter block, you can probably afford to test that limit on the stocker. Sounds like a science experiment.
 
I've never run any kind of boost on anything so I cannot make a personal comment. However if you haven't seen this thread it may or may not be relevant to your potential project.......

Twin TorqStorm 440 Build
 
IQ52 said:
I've never run any kind of boost on anything so I cannot make a personal comment. However if you haven't seen this thread it may or may not be relevant to your potential project.......

Twin TorqStorm 440 Build
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That was interesting. Thank you. I was going to run the single unit and I am looking for less boost than where they were having issues. I agree with one of those posters. It's a pretty good unit for a driver serious street car but it isnt a serious track unit. My 67 Cuda has factory air and that makes this unit attractive to me.
 
I think you could get close to 700 with boost if you build it right but if I was aiming for that power level with boost I'd be going Gen 3 Hemi or big block like a stroked 400... they have 5 head bolts per cylinder and a good percentage of those 400 blocks are unusually beefy. G3 5.7 blocks take quad-digit boosted power no problem.

But if you're planning a Ritter block build anyway I'd just save the nice internal engine parts for that build and put a TorqStorm on a mild-er ~400 hp setup with that 340 block for the time being, say to around 550 hp which is quite a bit safer. After all 340s aren't very common and are kind of valuable so it would be a bit of a loss if you happened to blow it up.
 
Dmopower said:
Hello guys and thanks in advance for the help. I am wanting to build a 340 stroked to 426. I have a good 70 340 block with std bore. I have milodon 4 bolt splayed main kit and a hughes girdle kit. I'll be using a Milodon 7qt oil pan. 234 242 cam. It's a street daily driver.9.5 or 10 to one comp. I'm thinking about adding a torquestorm supercharger down the road and am wondering if my block will hold up to the 700 hp level that this combo could achieve. Any help and insight is greatly appreciated.

Don
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1st and foremost...Precise machining.
Studs on all mains/girdle optional
1/3 block fill
.020 over would be ideal of not std. Thicker the better. Sonic test and sleeve any thin thrust side cyl.

The 70-73 blocks are my favorites for building big power. They are cast with reinforce bossing vertically in the center for more rigidity. Imo they worked any casting/core box kinks out by these yrs.
I have a june 1970 340 motor I run.
 
If the end goal is a 600+ hp engine I wouldn’t bother starting with a factory small block. Especially for the street. Spend mega bucks on a build only to leave a busted trail of parts behind you one day in the not so distant future.

You’re gonna need thousands and thousands of dollars in chassis and suspension upgrades too if you want to hook that thing up and not end up wrapped around a pole somewhere. So starting with a different engine or block shouldn’t be an issue.
 
Only If you drove it wot 24-7 guys..


You make it sound like it's going to grenade upon start up, like it idles 600hp..lmao..

Too funny.
 
MOPAROFFICIAL said:
Only If you drove it wot 24-7 guys..


You make it sound like it's going to grenade upon start up, like it idles 600hp..lmao..

Too funny.
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You wanna build a 700 hp small block but just listen to it idle? What's the point?

All I'm saying is if I'm going to build an engine that's gonna cost that kinda money for something other than dedicated race use, I'd leave some margin on the strength of the block I was doing it with. You know, instead of starting my build with a HP goal that's higher than what the block I'm going to use will safely handle under most circumstances.
 
Plymouth 65 said:
That's a stretch, you'll need an R block for that kind of horsepower. Also, 9.5/10 CR is too high if you're going to use a super charger. 65'
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Myth.

9.5:1 is about perfect for a boosted street engine up to moderate boost levels. My daily big block is 9.5:1 on 91 California junk gas and has seen 17 psi. And if the op is willing to use e85 then 11:1 and boost is not out of the question. It’s all in the tune up.
 
Lots of guys make 600 on turbo magnum stuff. It’s not uncommon at all. @Dmopower take your stroker kit and put it in a magnum block. Sell the 340 to someone restoring a car, they’ll pay good money for it.
 
My personal opinion is ditch the supercharger and put a turbo on it. Less parasitic drag, easier to adjust the power level and when off boost the engine will run just like an NA engine. The boost is only there when you stab it.
 
TT5.9mag said:
My personal opinion is ditch the supercharger and put a turbo on it. Less parasitic drag, easier to adjust the power level and when off boost the engine will run just like an NA engine. The boost is only there when you stab it.
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I wanted to do a turbo on my duster until I realized how huge of a fabrication project it would be; headers, hot-side plumbing, mounting the turbo itself, intercooler and cold side plumbing, plus engine management to control boost. A centrifugal blower is basically a bolt-on and the controls are more straightforward. For a turbo setup I'd need to blast apart the entire front end of my car and probably relocate a bunch of things like the battery then proceed to fabbing everything. I'd love to be wrong but nobody makes turbo kits of any sort for A-body Mopars and I don't have the fabbing experience to go into it gung-ho.
 
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