4 bolt main?

[DTrain]

How do you tell the difference between a four bolt main and a two bolt main without taking it apart? A guy came over looking at some parts to buy and asked about the '79 350 I have sitting on the stand. He asked if it was a two or four, I said four. I started thinking about it after he left and I really don't know for sure which it is. I pulled the motor with 129,xxx original, unmolested miles, so knowing if it were a two or four bolt main would help with negotiations. Any help would be appreciated. Thanks guys

[codyC10kid]

The side of the block right in the middle it will say 010 Its a four bolt,I also herd it will have a number 4 bolt aslo a four bolt main....My 2bolt main it has numbers 088 with is a 2 bolt...i own and I'm building them both...Other numbers might be out there but i only have 3 motors and them are the numbers

[Captkaos]

010 has nothing to do with the main cap configuration, it is the core identification number for the side of a SBC.
The only way to tell if it is a 4 bolt is if you pull the pan.

Example, one of the most popular quoted block casting numbers is 3970010, it was a 2 OR 4 bolt block depending on what it was to be installed in.  What made it a 4 bolt was a machining process, not the core designation.  There are a handfull of casing numbers that were ONLY 4 bolts, and most were one year only stuff, others were late model Truck blocks.

[codyC10kid]

010 has nothing to do with the main cap configuration, it is the core identification number for the side of a SBC.
The only way to tell if it is a 4 bolt is if you pull the pan.

Example, one of the most popular quoted block casting numbers is 3970010, it was a 2 OR 4 bolt block depending on what it was to be installed in.  What made it a 4 bolt was a machining process, not the core designation.  There are a handfull of casing numbers that were ONLY 4 bolts, and most were one year only stuff, others were late model Truck blocks.

Hmm i was told/thought wrong..i ges i know now

[rickyharp]

The way the guy at the machine shop I go to told me a quick way to tell without taking things apart or looking at numbers is in the front of the motor just under the intake manifold on the block on the left side [ facing the motor] should be a little pipe plug that indicates a 4 bolt main block.This trick has always worked for me.

[DTrain]

I finally did the smart thing and pulled the numbers. Looks like I've got a two bolt main. Not the end of the world, but a little bit of a bummer. Oh well, I put it on Craigslist, guess I'll see what happens now.

[codyC10kid]

I finally did the smart thing and pulled the numbers. Looks like I've got a two bolt main. Not the end of the world, but a little bit of a bummer. Oh well, I put it on Craigslist, guess I'll see what happens now.

2 bolt mains are stronger when you buy the 2 to 4 bolt main splayed caps..and ARP bolts

[Fairlane514]

In order to use the aftermarket 4 bolt caps you then have to line bore the block, which can raise the centerline of the crank. This in turn can cause bellhousing and transmission alignment issues. You can use offset dowels to correct the bellhousing alignment. It can also cause issues with the cam if you are stroking the motor.

Two bolts are pretty strong, unless you are going with high horsepower numbers.

[Skunksmash]

I gotta ask... at what point do you even need a 4 bolt main? I see plenty of guys making sure they get one, only to do a stock style rebuild with maybe a few minor upgrades lol

[codyC10kid]

I gotta ask... at what point do you even need a 4 bolt main? I see plenty of guys making sure they get one, only to do a stock style rebuild with maybe a few minor upgrades lol

i was reading on the internet somewhere that there rated to like 500 hp and it if have a 4 bolt and ARP studs its good to 700hp

[Captkaos]

I gotta ask... at what point do you even need a 4 bolt main? I see plenty of guys making sure they get one, only to do a stock style rebuild with maybe a few minor upgrades lol

If you are building a full dedicated drag or a circle track motor.  And then you will get a 2 bolt and splay the caps.

If it is a street motor, 2 bolts are fine.