Thread: 2 bolt or 4 bolt

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Ive heard that sbc 2 bolt is actually stronger then a 4 bolt main. I guess the 4 bolt crack easier. Im wantin to put a 350 in ym camaro, and i allready have a 2 bolt block. So what shoudl i do?

The 010 2 bolt block has more nickel in the casting....use the 2 bolt & have it spayed....4 bolts will crack, but you got to really throw it to it to crack a block. So I say - build the 2 bolt.

yea.. i heard you can get something called hard coat or something coated in teh water jackets to strenthten teh block. I am wanting a engine, that is capable of producing high horsepower, but still a daily runner. I am expecting about 650 hp, with a blower, and maybe a lil spary here n there.. is that too much for a 2 bolt?

lol.. i do read alot of magazines.. it gets my brains agoin. Do you think that is possible?

Anythings possible, just depends on your wallet.... Buttttttt 650 horses ain't very streetable...

lol.. ok.. but what about 600? heeh

well what do you think the max is..

550 HP, is streetable and a 2 bolt should take it, there are 4 bolt conversions for 2 bolt's anyway. I'd trade that Gen 3 for a late Gen 2 if you want that kinda HP, they look cooler and take the power very well, I coulden't gaurentte that on a Gen 3, I think there sub frame is built lighter and may not take that kinda power as well.

yea.. i would like to get a older maro.. but they are expensive, adn there dosent seem to be any around here

We recently went through this same question on another thread where I visited the shop of local racer Joe Butler who showed me the bottom of the cylinders of several different blocks lined up for boring and honing. Joe emphatically stated he would not use a 4-bolt 400 block for his racer and I casually transferred that to the case for a 350 4-bolt. It doesn't matter to me since I will be lucky to get 300 H.P. (probably not) and certainly not 400+ with my mild 350, but as usual Techinspector1 may have said something important in that there is a difference between the 350 and 400 bearing webs. Anyhow it looks to me that maybe the 400 block is stronger without the two extra holes and that case is clear. For the 350 the debate rages on, but reading I have done recently seems to indicate that a 2-bolt 350 with the 10-degree splayed extra bolts for a splayed-4 bolt is really the very best, but again as I say it looks like up to 400 H.P. it really doesn't matter. On the web site called something like "Ryan's Dynoed Chevy" results (I have lost the URL for that site but it is easily found) there are documented cases of streetable 350s OVER 500 H.P. and of course more is always better (????) but I would think anything over 500 H.P. on the street would be tough to handle, prone to traffic tickets and also require considerable chassis improvement for street handling in cases other than straight line runs. I am just chatting, but I wish I had read Ryans 109 Dyno Runs before I bought the parts. There is more information there than in a closet full of old Hot Rod magazines!

Don Shillady
Retired Scientist/teen rodder

In your case, there is a few options. 1) go with a few less HP. 550? your kidding matt. im leaning towards 400 as the limit if you live in/near a city. 2) build a good frame under your camaro and bolt the shell over it. Pro70 is the local expert on this approach. 3) locate an older beater camaro and use it as a template. Salvage titles are Always an option if their clean enough. With the 2 bolt block, a 4 bolt conversion is always a good idea. Forged/cast iron cranks shouldnt be that hard to get your hands on, so get one asap. Forged is always better-of course.

Originally posted by Streets
Well Matt, IF you think 550 HP is "streetable", I'll put the Huffered 383 stroker back in my Pail and take out a million dollar life insurance policy on YOU and you can take the pail down the street with the pedal to the medal.. (IT Gets kinda squirrely from 70 to around 160 and more so if ya happen to just let off it quick like) I'll be 1 mill richer and you'll be pushin up daiseys.. ON the track its fine with the 555HP But, that's only a ¼ mile and a ½ mile shutdown.. Besides with THAT much HP ya got tons of heat and noise and the cops would love ya.. They'd get writer's cramp in their fingers!! 550 HP Is NOT "streetable" at all!!

True, maby in a heavier car ( Chevelle, Impala or other such large car ) it may be streetable with the right amount of traction but, not practical because of the heat and noise as you said but deffinetly not in your pail, it's way to light.

thanks for the help fellas. I called teh machine shop, they said ti would cost about 450 bucks to get the block converted to a 4 bolt main, which with that much money, i could easily find a nice 4bolt 350, and sell the 2 bolt i allready have. Which by teh way, if anyone is interested, make an offer. Thanks!

Originally posted by Streets
Sorry matt, you don't idle off the crosswalk/stop light with 550HP in anythang!

Ok Streets, I belive ya. The more and more I think about how much 550 Hp really is, that is Excessive for a street car but what about a pro street that is still road legal? like proz is doing.

what do you think teh 350 2 bolt block it worth? its bored 30 over, and is in good shape