Strong Bottom End

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EXcappa

EXcappa

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Hey Guys,

I've read a fair bit that a 4bolt conversion is not the way to go on a factory 360 block.
Is it due to thin webbing?
What about splayed 4bolt caps, will that be an option? Or should I just use billet 2bolt caps

I currently have a 4" Scat forged crank, Scat H beam rods, ARP 2000 bolts and forged pistons.
Studs and factory caps
 
Mopar blocks use big main bolts and the casting does not have the meat for outer bolts, even smaller ones. So if you feel the lower end needs more, get a better block that's designed with them. Billet two-bolt caps will give you all the bottom end strength the factory block can support. You can also go with a lightened crank and aluminum rods if you need more rpm.
 
ARP studs, billet caps and a stud girdle. I believe hughes makes a girdle for the small block. splayed caps are an option but I am not sure if they're worth the hassle. It depends how far you're gonna twist the thing. It is a cast steel crank I presume.
 
omahamoparguy said:
ARP studs, billet caps and a stud girdle. I believe hughes makes a girdle for the small block. splayed caps are an option but I am not sure if they're worth the hassle. It depends how far you're gonna twist the thing. It is a cast steel crank I presume.
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EXcappa had said;
I currently have a 4" Scat forged crank, Scat H beam rods, ARP 2000 bolts and forged pistons.
Studs and factory caps
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Post #2 & #3 nailed it!
 
Thanks Gents, looks like I'll be ordering some 2bolt billet caps.
Which company should I order from. I want quality not cheap junk.
 
As no one most of us knows have ever seen a factory main cap fail just use ARP studs, balance well and use a girdle. You'll have no problems with the bottom end. Dan
 
75Sport said:
As no one most of us knows have ever seen a factory main cap fail just use ARP studs, balance well and use a girdle. You'll have no problems with the bottom end. Dan
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I've seen a couple of broken caps. Both were circle burners and I suspect detonation. Of course, the tuner said no detonation.

That said, if you're breaking caps and install stronger caps it will fail something else.
 
Just throwing this out there as to the strength and longevity of stock block mopars, and the experts can argue all they want, but I've personally run the same 340 in my dart for close to 40yrs now. Its made lots of 11 second passes on junk slicks, with mufflers. Its had the valve covers off a few times to set last and replace springs and retainers. Took off double springs to run singles. This was a low mileage motor to begin with. All home built by my father, a lifelong mopar mechanic and racer. It has factory pistons, rods crank with old direct connection rod bolts. A few oiling mods to block, milodon 8qt pan and pump. Stock caps, stock main bolts. Solid 515" cam, and home porting, along with a good valve job and some milling on the X heads. Stock 273 rockers, single plane intake, heddman big tube headers and al , stock external accessories for a stocking look. All stock electronic ignition. Granted, it's no daily driver anymore, has a 4speed, 4.88 gear. Just a weekend cruiser and occasionally kills a new camaro or stang. This motor has been powershifted at 7000rpm it's whole life and a few missed shifts have pegged the fact at 8000!!! This motor is nothing special, no exotic parts and it's been through the ringer. Burns no oil, hasn't broken any engine parts, and is a blast to drive. The Nay Sayers can say what they will, but you don't need all those fancy exotic parts to run in the 11s with a full bodied, uncut, steel car. I know for a fact that the factory parts are far stronger then they get credit for. Key is finding parts that don't have 200kmiles and proper assembly. May not make 5 or 600 hp,but who really needs to go faster then 11s on the street. Especially when all you gotta do is lash the valves and change the oil once a year. That's why the engine we built so long ago is still there since I bought it from my dad. It works and has no problem killing 383 chevys, or a lot of big blocks. These motors are stronger then a lot of guys give them credit for
 
Dartish said:
Just throwing this out there as to the strength and longevity of stock block mopars, and the experts can argue all they want, but I've personally run the same 340 in my dart for close to 40yrs now. Its made lots of 11 second passes on junk slicks, with mufflers. Its had the valve covers off a few times to set last and replace springs and retainers. Took off double springs to run singles. This was a low mileage motor to begin with. All home built by my father, a lifelong mopar mechanic and racer. It has factory pistons, rods crank with old direct connection rod bolts. A few oiling mods to block, milodon 8qt pan and pump. Stock caps, stock main bolts. Solid 515" cam, and home porting, along with a good valve job and some milling on the X heads. Stock 273 rockers, single plane intake, heddman big tube headers and al , stock external accessories for a stocking look. All stock electronic ignition. Granted, it's no daily driver anymore, has a 4speed, 4.88 gear. Just a weekend cruiser and occasionally kills a new camaro or stang. This motor has been powershifted at 7000rpm it's whole life and a few missed shifts have pegged the fact at 8000!!! This motor is nothing special, no exotic parts and it's been through the ringer. Burns no oil, hasn't broken any engine parts, and is a blast to drive. The Nay Sayers can say what they will, but you don't need all those fancy exotic parts to run in the 11s with a full bodied, uncut, steel car. I know for a fact that the factory parts are far stronger then they get credit for. Key is finding parts that don't have 200kmiles and proper assembly. May not make 5 or 600 hp,but who really needs to go faster then 11s on the street. Especially when all you gotta do is lash the valves and change the oil once a year. That's why the engine we built so long ago is still there since I bought it from my dad. It works and has no problem killing 383 chevys, or a lot of big blocks. These motors are stronger then a lot of guys give them credit for
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Those DC Rod bolts were really good bolts.

There is a big difference between 450 and 600 HP.
 
yellow rose said:
Those DC Rod bolts were really good bolts.

There is a big difference between 450 and 600 HP.
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Very true. But I see a lot of so called 600 hp cars that can't get out of their own way. Throw a bunch of hi dollar parts at it. Spend more time fixing it then they do driving it, and still run 12s if they're lucky, then go work on it some more. Kinda like the Ford and Chevy guys. I guess I'm just someone that would rather drive it, enjoy it, and not worry about breaking something every time I beat the snot out of it. Spent ALOT of Sunday's at the strip. Drove it there, bolted on slicks, ran in the 11s and drive home. Never opened the good or turned a wrench. Just saying you can build a decent running street car, minimum maintenance, and look Damn near stock with decent factory parts. Sad thing is those good factory parts that aren't roached are pretty hard to find now. I was lucky my dad hoarded a ton of parts from the early 70s and preserved them. Including a new, factory warranty 340 shortblock. If I ever break the one I've got, I think I'll stick my nos racer brown 528" solid in it, rebuild another set of x heads, and run it til I'm too old to push in a clutch pedal. Not sure about you guys, but I think running an 11second car on the street, that idles in traffic, runs 180° in traffic, and requires minimal attention has been doing it for 40 years is more fun then constantly tuning and wrenching.
 
All good points thanks.
Any recommendations for billet caps?

It weighs 3570lb with driver
Soft launch, first time racer 11.2@121
 
Try Mancini I think they have what your looking for.
 
yellow rose said:
Those DC Rod bolts were really good bolts.

There is a big difference between 450 and 600 HP.
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I'm thinking you're probably right with the 450 hp. Never been dynoed, I always figured it is what it is. But the formulas I've looked at considering the weight and trap speed put it between 434 and 446 hp, depending which one you use. Not bad for stock stroke, stock bore 340 I figure. As far as the difference between 450 and 600, I always figured that was just the push of a button.lol. tossed that around for years now, the kit is still in the box on a shelf. Change the tune a little bit,and I bet the engine will still live longer then the drive train parts if it hooked. Not sure how to make a street tire hook with a stockish suspension, 4.88 and 4 speed. But it sure is fun on the back roads to dump the clutch at 5k and go through the gears just like my dad did when we put the motor in. THAT my friends is what got me into hot rodding and the memory of that first burnout, in that "stock" dart is still there like it happened yesterday.
 
I had issues with clearance when i used the arp studs. I put them back in the box and sold them. Can't remember exactly but I believe it was around the oil pump and I was not willing to grind down a washer and the stud for clearence

Using stock maincap bolts now with around 450 hp in my 418 w2.
 
450hp will run forever with stock caps. 500+ will not IMO). Small block caps don't usually walk much, but they do deflect as power goes up and i have seen broken caps from repeated flexing. Bigger main clearances help when the cap deflects and the edges pull in. That's where the extra space is for. Detonation and high rpm with poor balancing will break them over time. I do not believe in girdles simply because for me the return on investment tips when you add in the the cost and setup in addition to the caps, studs, and align bore/hone. If you need a girdle - you need a better block.
 
dodgedifferent2 said:
I had issues with clearance when i used the arp studs. I put them back in the box and sold them. Can't remember exactly but I believe it was around the oil pump and I was not willing to grind down a washer and the stud for clearence

Using stock maincap bolts now with around 450 hp in my 418 w2.
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You either use a stock bolt under oil pump or you use a stud with thinner 12 point nut and grind it down .050 ish...aftwr that the only issue is line honing after the studs, typically, scooch the caps around. Yes I've used the factory main bolts many times, and even the one bolt under pump and rest studs . Works fine.
 
No been around a long while. Have modified a lot of stuff over the years and it irks me when you buy stuff and it's junk.

Chinese mentality, capitalism and us consumers demanding cheaper and cheaper but also wanting quality. Guess we can't have it all.

Moral of the story I would not pass 10 cents to arp
 
dodgedifferent2 said:
No been around a long while. Have modified a lot of stuff over the years and it irks me when you buy stuff and it's junk.

Chinese mentality, capitalism and us consumers demanding cheaper and cheaper but also wanting quality. Guess we can't have it all.

Moral of the story I would not pass 10 cents to arp
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I agree, it's a pisser nothing fits. So far, all my bitching to the people who make the junk has done nothing, except raise my blood pressure.

Now, I just expect to modify everything when I get it, and if I don't I count it as a blessing. I'm too old to fight with them anymore.
 
Tired of the snowflakes that think everything should fit because they paid money for it. Whaa, whaa, whaa! It's not gonna, just fix it or send it back. We raised the lazy kids building this crap, or the kids who are so cheap they want the Chinese to build it. Blame yourself!
 
IQ52 said:
Tired of the snowflakes that think everything should fit because they paid money for it. Whaa, whaa, whaa! It's not gonna, just fix it or send it back. We raised the lazy kids building this crap, or the kids who are so cheap they want the Chinese to build it. Blame yourself!
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Dude.. perfect...lol
 
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