cutlasskid84

Hi, just pulled my stockish 350 from my cutlass. My plans are to build a 383 with vortec heads modified for higher lift. With a possible 100-150 shot of juice. I didn't build this motor originally, so I never knew what was inside, but awhile back I ran the casting # on the block, which is 3970010. What I came up with was a 4 bolt block, mid 70s, from a truck. Well, when I pulled the pan today, I found I have a 2 bolt. So I'm wondering if this block will be able to handle the power I'm planning to build. Thanks for any and all advice.

Villain281H

iTrader: (5)

All motors survival rate is based on what you builb them with and what you plan to use them for.

I've seen 2-bolt mains last 7+ years if built right (not just necessary with the right parts, but put together correctly).

Derek

Tiresmokin

My machinist told me years ago to go with a 4-bolt block before a forged crank. If you are going with forged internals and good rods, I would convert the block to a 4-bolt. 100-150 shot now, 250-300 later......

78TA

iTrader: (1)

You can always spend a little extra, and turn your two bolt into a splayed main 4 bolt. Which is very strong. But not very cheap.

Tiresmokin

Where are you located? I have several 4-bolt blocks

1FSTZ71

iTrader: (11)

I've heard different engine builders have different opinions on the splayed debate. To be honest, if you don't plan on pushing much more the 500hp, a 2 bolt with studs and assembled properly would work out nice.

cutlasskid84

Tiresmokin, I'm in lake city, iowa, which is about an hour and a half north of des moines. Not sure how far that is from you. Thanks.

BULLET99Z28

iTrader: (9)

Yup,put some main studs in it. Should be fine

Novas Forever

Go for main studs and careful assembly, I had a 2 bolt block for my 406 and it was fine.

NemeSS

iTrader: (127)

have built stud 2 bolt 383 775+ rwhp turbo engine going on 3 yrs
in a low 9 sec-hi 8 sec. 3rd gen camaro
have built other 400+hp 2 bolts, turbocharged
comes down to assembly and machining of block in the end and clearances
of components put together correctly for intended use

91camaross

iTrader: (1)

i have made 698 rwhp with no problem

Super Auto Depot Inc

Hello,

Really there is a hot debate as to whether or not a block with 2 bolt mains, or a block with 4 bolt mains is any better than one another.

If you are talking in terms of RPM's some people would argue that a 4 bolt main block would hold up under the stress better than the 2 bolt main block.

We have built many 2 bolt mains, and many 4 bolt mains from 500 hp on up. Some of the 2 bolt mains we have built we used superchargers and low compression dished pistons. In my experience you really won't notice a huge amount of difference between the two. A lot of that has to do with how well you put your engine together paying extreme attention to clearance issues.

How much horsepower and torque were you expecting to put down on this engine? I would say that a 2 bolt main would handle upwards of 550-650 horsepower if built correctly. Also balance plays a major role in this.

As always, if you don't feel safe running a 2 bolt main, change it over to a 4 bolt main for ease of mind. Good Luck!

b00sted

iTrader: (7)

I'd say if you're building a 350 based sbc go with the 4-bolt block. If you're building a motor with a 400 sbc, go with the 2-bolt. The 2-bolt 400 is much stronger in the webbing than the 4-bolt...

Ryan02SS

iTrader: (3)

I've ran 2 bolt 350-360ci's in my Marine builds up to 425HP. They've lasted a long time some approaching 850 hours. These are WOT built motors and see extended time periods 2-3 mins at WOT. My last 355ci 2 bolt all cast setup lived 678 hours at WOT spinning 6600rpms.