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Author Topic:   2 bolt vs. 4 bolt - whats better?
rogracer2
Dirt Maniac

Total posts: 119
posted January 28, 2005 04:44 PM  
I need to replace my motor - so I was wondering what the advantages are for a 4 bolt vs. a 2 bolt Chevy 350 block. Any advice?

BIGDADDYBOZ
Dirt Freak

Total posts: 466
posted January 28, 2005 05:41 PM  
I've ran 2 and 4 bolts both they both blow up the same. Alot of guys around here sell their 4 bolts and buy 2 bolts for cheaper.

o5racer
Dirt Freak

Total posts: 402
posted January 28, 2005 07:13 PM  
I have read in a couple different places that 2 bolts are supposed to be good for 500HP if assembled properly.

redneck racing
Dirt Forum Champ
Total posts: 860
posted January 28, 2005 08:27 PM  
I agree with BigDaddy ive blown up both also but stick to the 2 bolt they are cheaper. Eddie

racin78p
Dirt Freak

Total posts: 333
posted January 29, 2005 02:52 AM  
A 4 bolt main should allow you to turn it tighter. Alot tighter. I have turned a 2 bolt up to 7000 r's without dumping the bottom end. BUT!!! That is with a good rotating assembly that has had a good balance job done. I agree with the other posts here, both can and will go boom. If you don't plan to turn higher than 6500, then a 2 bolt should do the trick for you. I would always get it balanced though. That's just me. I sleep (and RACE) better at night that way.

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racin78p
if it ain't fun, then don't run

redneck racing
Dirt Forum Champ
Total posts: 860
posted January 29, 2005 10:33 AM  
Ive turned my 2 bolt to 7200rpm and its guaranteed to 8000rpm its not balanced has stock crank, Keith Black 10-1 pistons, Eagle rods and moly rings. Eddie

joetaylor
Dirt Forum Champ
Total posts: 640
posted January 31, 2005 08:21 PM  
2 bolt I all I run BUT I stud them seems to help but as outhers stated they bout blow up I use 2 bolts caus I can find them much easyer but I find a 4 bolt block then I use it until IT breakes hopes this helps up out

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if every thing is under control your not fast enough

racin78p
Dirt Freak

Total posts: 333
posted February 01, 2005 05:32 PM  
Hey eddie: Who's building your 2 bolts? 8000 gauranteed? No one I know of will put their stamp on a stock, non-balanced with nothing other than a rod up-grade for a 2 bolt main! They are lighter, can be turned high rpm's if put together right with the right stuff, but I can see the bottom end starting to flex enough after 7500 rpm on a 2 bolt and BOOOOOOMMMM. I give you credit that you have such a mini mouse that cranks right up there, but I never have nor anyone I personally know has. I assume heads/valve train shored up too? 8000 rpm. Wow!!! You da' man!!!

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racin78p
if it ain't fun, then don't run

hobby10k
Dirt Freak

Total posts: 226
posted February 03, 2005 04:45 AM  
turning a stock non balanced engine 8000, thats nuts!!! well a studded 2 blt is fine and will hold up, I always balance my stuff, I run cheap stock parts so I haft to have a little something on my side.

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LIVE RACING, WHAT ELSE IT THERE?

dirty58
Dirt Maniac

Total posts: 115
posted February 06, 2005 02:44 PM  
the webbing in a 4 bolt is to weak I turn my 2 bolt 7500 all night never worry balanced with a stock crank good rods and bolts my opion thats the way to go

wrenchturner10
Dirt Forum Racer

Total posts: 80
posted February 06, 2005 06:02 PM  
If you want a very dependable 4 bolt, take a 2 bolt to the machine shop and have splayed caps installed.It ain't cheap but will make a very strong bottom end.

02 Blewbyu
Dirt Full Roller

Total posts: 48
posted February 18, 2005 11:12 AM  
I was once told along time ago that the 2 bolt blocks have more nickel content making them stronger. I cant remember where I heard this and I dont even know if its true or not. Any one have an answer.

Xtreme12x
Dirt Forum Champ
Total posts: 874
posted February 18, 2005 11:30 AM  
Run a 2 bolt main block, and when you can afford it, take and have splayed caps put on. We run a lot of 2 bolt stuff in claimer motors. It's not RPM's that blow motors, it's that the clearancing is wrong, and that they are assembled improperly. Not saying that anyone here builds engines wrong but 9 times out of 10 it isn't a part failure.

nailngoracing
Dirt Maniac

Total posts: 170
posted February 20, 2005 02:02 AM  
the two bolt is lighter!!!!!!!!!

Eljojo
Dirt Forum Champ
Total posts: 968
posted February 20, 2005 02:11 PM  
Yeah, Nailngo....and I read on here that the 400 small block is 200 pounds heavier! (j/k!)

wetwolfone
Dirt Full Roller

Total posts: 51
posted February 22, 2005 01:56 PM  
quote:
Originally posted by Eljojo:
Yeah, Nailngo....and I read on here that the 400 small block is 200 pounds heavier! (j/k!)

They were talking about the rule book. If you run a 400, minimum weight is 200 pounds more than a 350 car.

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