So I pulled this motor out of an 87 truck. I went looking for the engine stamp code so i could learn a bit more about it before I started tearing it apart, but when I looked at the back ledge for the code, all I got was this...


Now this clearly isn't the casting number I was expecting, and I couldn't see anything on the passenger side ledge although there's a good bit of wires/pipes/lines/tubes on it still that were kind of all over the place so I might have simply missed it. Is there any information from these numbers other than its obviously a 305? Is there a chance the casting number is somewhere other than the back ledge like I am used to?

 

It's a 305 block. That's about all that tells you. At the end of the day, that's the only thing that you need to know from block numbers. Anything of actual importance those block casting numbers won't tell you anyway. Roller cam? Won't know till you look. 'Good' heads? Won't know till you pop valve cover and see what they are. What pistons/rods/crank are in it? Won't know till it's inspected. It's had 30 years of life probably at this point and could have been changed to something it didn't leave the the factory as.
It only implies that its a 305 still. It really only tells you it's a small bore sbc.

 

That's not a "stamping".

Here's the usual place, just like your pic:



Might want to look a little to the right of your photo.

You might also find the last 3 digits here (above and to the right of the crank)



and/or on the side of the block or on the front although that last might be under the timing cover.

 

Guess I should just get to disassembly then. I have a 350 goodwrench block next to it, was gonna build that but its a completely bare block, doesnt even have the main caps anymore, but I did get the full heads with it. I was comparing prices and decided to go for this 305 since its a complete package and work with it til i have the time and funds to build the 350 properly. No sense slapping together weak parts on a good block when i can use a 305 til the 350's done . The most annoying part of the 350 block is that although its a 4 bolt main, all 4 bolts are straight and all the 4 bolt caps i've found locally are the standard ones with the outer bolts at an angle. Gonna be some time til i can fix that fella up.

 

Of course: that's the stock crap. Grossly inferior to "splayed" ones. Designed for, and really only good for, the kind of stress that a truck puts on them. Not worth much for "performance". Not even better than only 2, in some situations, because the extra 2 holes in certain castings actually weaken the block more than the extra bolts strengthen the retention of the caps.

Those are aftermarket. VASTLY superior to the stock setup.

Take the flex plate off to get the last 3 of the block casting #. Will also tell you whether it's a 1-pc or 2-pc rear main seal, if you haven't got to that point yet.

Take the VCs off and get the head casting #s.

No need for "disassembly".

 

That sets off a few warning bells for me. Although new main caps can be installed and even converted to splayed bolt caps, it's not just a simple bolt on and go. Whenever you replace main caps, the block should be line honed to make sure they're all straight and square. Not a difficult job for a good machine shop but it does add to the cost of a rebuild. Since the block is bare, it's probably going to need to be bored out and probably decked to make sure everything is square and true. As nice as it sounds to rebuild your own engine, to do it properly, the cost of all the extra machine shop work can easily exceed the cost to buy a new short or long block.

 

This will sound wrong to most of you, that are not familiar with the common Machine Shop modifications for the Gen-1 Small Block Chevrolet.

I consider Stock 4-Bolt Main-Cap 350s to be inferior in terms of durability for Performance use.
I would prefer to use a Stock 2-Bolt 350 over a Stock 4-Bolt 350, for Performance use.

The Stock 4-Bolt Gen-1 SBC does not possess the Material (Main Web and Core) to be durable enough for Performance use.
(4-Bolt 400 Blocks being even worse than 4-Bolt 350 Blocks).
I have Cracked/ Broken my fair share of these Blocks when trying to push them beyond their capability (as well as seen many other Builders do the same).
The small amount more Material, that the 2-Bolt Block is afforded, does actually make for a more durable Engine in Performance use.

Ideally (if required to use a Stock 350 Cylinder Block) I would use a 2-Bolt 350, and have the Machining done to implement Splayed 4-Bolt Main Caps
(Main Caps #2, #3, and #4 will be Modified... the #1 and #5 Main Caps will have to remain Stock).
The Splayed bolts actually engage the block in a more desirable area, than the Stock 4-Bolt Main Cap Bolts.
The location of the Bolts in Stock 4-Bolt Main Cap Blocks, actually makes for a weaker Main-Web area with less Material.

And for any of you wondering, Big Blocks are much better off in terms of Stock 4-Bolt Main Caps compared to the Small Blocks.
The #1 and #5 Main Caps can use 4-Bolts on many Big Blocks.
While Splayed 4-Bolts Main Caps are superior, the Stock Big Block 4-Bolt Main Caps are decent.

 

My dart Big M block uses splayed caps but I also ordered it with billet caps for extra strength. I cracked the webbing after breaking the engine a couple of times on my first Big M block. $2000 into the scrap metal pile. Haven't had a problem with this block and it makes more power than the first one was making. For big HP, quality internal parts is a must for long life.

Stock, OEM block SBC and BBC can still make a lot of power but they do also have a lot of limitations and life expectancy. When comparing dollars to dollars, you'll get a much better bang for the buck by simply swapping to an LS engine instead of the old style SBC. The production design of the LS block is far superior to the SBC blocks.