350 ID Help

[chengny]

Don't assume the lack of a plug definitely means it's a 2 bolt. I have only found the opposite to be consistently true - that a plug means a 4-bolt. But a no-plug doesn't necessarily mean it's a 2 bolt.

Did you miss this?


BTW - this indicator has proven 100 % positive so far but there is a twist. Just because there is no pipe plug does not mean that the block is not cast/drilled for 4 bolt mains. I once bought a used engine that did not have the plug and assumed it was a 2 bolt. But when I pulled the pan, it turned out to be a 4 bolt.

 

[Boone83K10]

Yeah I saw it.

Meh I doubt mine is 4 bolt. its a 70-76 truck block with 882 heads that the PO "built" with a small cam and some porting.

 

[chengny]

Don't sound so depressed, it's not a big deal anyway. There is absolutely nothing wrong with the 2-bolt design.

The belief, that 4-bolt mains are an indication of an engine's superior quality/strength, has somehow achieved "gospel" status. I think this is a fallacy.

IMHO, it is totally based on hearsay and rumors. This misinformation has been spread -primarily on the internet - by a bunch of race car posers. I am talking about guys with nothing better to do than visit forums and spout off. Just to appear to be "one of the guys", they repeat all the common buzzwords and conventional wisdom they have heard.

It doesn't take long. Soon, what was once just an opinion, suddenly becomes a "known scientific fact".

In the case of 2-bolt mains, GM built and sold these engines (successfully) for many years - across all their model lines. One would have to assume, that if the 2-bolt was found to be a faulty design, it would have quickly become public knowledge. At some point, GM would have been forced to make a business decision (i.e. to cease production of the 2-bolt and only offer the 4-bolt version).

Unless you are talking about some unusual circumstances (stroked engine, running nitrous, boosted intake, extreme HP, etc.), don't worry about it. The number of bolts that fasten the main bearing caps to the block is not a factor.

This just popped up on my screen - so I'm out for awhile:

You must be registered for see images attach

 

[72chevy2door]

@chengny. I have a 350 block that's fully assembled and that port that's above the timing chain is not there. How else could I tell if it's a 2 or 4 bolt block without pulling the pan?

 

[72chevy2door]

here is the stamping on the front pad. It also has 882 cast iron cylinder heads

 

[68post]

I think it is a '74 and if so it came with a 2bbl and an auto trans.

Casting code on the rear of the block tells us more , but nothing will tell you for sure if it is 4 bolt mains without looking.

 

[firebane]

KO716CMP
K = St.Catherines, Ontario, Canada
07 = July
16 = 16
CMP = L98 350 from a 1991 or so Firebird with TBI
TBI on it.

http://www.73-87.com/chevy_ids/scode3.htm

The 14Y number SHOULD be a partial vin for your vehicle.

 

[68post]

KO716CMP
K = St.Catherines, Ontario, Canada
07 = July
16 = 16
CMP = L98 350 from a 1991 or so Firebird with TBI
TBI on it.

http://www.73-87.com/chevy_ids/scode3.htm

The 14Y number SHOULD be a partial vin for your vehicle.

It's a CMR suffix

 

[firebane]

It's a CMR suffix

So it is! Well then that means the bore needs to be measured out because CMR refers to a 305 not a 350.

I ran I to this same issue with my truck.

 

[68post]

So it is! Well then that means the bore needs to be measured out because CMR refers to a 305 not a 350.

I ran I to this same issue with my truck.

There is a 1974 350 and a 1978 350 with CMR also.
145 hp and 220 hp. The '78 is a vette listing - don't know if that helps the chance of being a 4bolt !

 

[firebane]

There is a 1974 350 and a 1978 350 with CMR also.
145 hp and 220 hp. The '78 is a vette listing - don't know if that helps the chance of being a 4bolt !

Man is my brain not working this morning LOL.

I would say or hope that this is more the LG4 version of the engine rather than the L82 but who knows.