Im building a sbc 350 enigne. its a 3970010 block. from a 64 truck. not sure if it is a 2 bolt or 4. if its a 4 bolt would it be worth keeping or should i upgrade to an 80's or 90's block. i hear these blocks can take some power, but im not sure. i am shooting for 400 hp. plan to bore it .03 over n 400 crank in it. basically a 383. if its a 4 bolt should i built it or should i upgrade to another block. would appreciate a response

 

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have it magnafluxed and pressure tested for cracks. For that low of power goals either 2 or 4 bolt will be fine, a newer block will accept roller cams which would be my vote hands down.

 

Look by the oil filter housing to see if its a 010 or 020 casting. This will tell you if its a high nickel content block (witch is very good). Really the only way to tell if its a 2 or 4 bolt is to pull the pan and look. Either way it will be good for what you want to do with it. Iv'e seen 2 bolt 383's wing 7500 rpm all night long in circle track cars without missing a beat. In my opinion a 2 bolt (in some applications) can actually be better than a 4 bolt.

Gm ran those blocks for years, nothing wrong with them as long as you don't have to bore the crap outa it to clean it up.......

 

The 010 by the oil filter housing is merely representative of the fact that the block has a 4.000" bore. It's the casting number.

The "010/020" for nickel/tin content is located under the timing cover.

 

your right, but anytime I have seen a nickel block marked 010-020 under the timing cover its also marked on the driver side of the block???

 

im going carburated to broke for all those computers lol

 

thats is what i gave read. but the number by oil filter can tell you its bore????

 

if i do decide to build this 64 block, will i be able to use any sbc 350 heads. or am i limited to a certain type of head since my block is a lilte older. i dont know much but am trying to learn more. just trying to figure out if my block is worth the build or if i should just upgrade

 

According to Mortec.com, your casting numbers could be for a 1969 302 (from the Z28's), a 1969 327 (from the trucks and industrial), or a 350 from 1969 - 1980. I had the same issue with mine. You'll have to 1) see how many bolts, and maybe 2) get the casting number off the crank before you'll know for sure if it's a 350. The 302's had 4 bolts as well as the 350's, and the 327's had only 2 (but so did the 350's) - thus why you sometimes have to check crank casting numbers to know for sure.

These can very well turn out to be 327 motors, but there's still hope in that - some of the 327's were large journal motors, and thus accept the 350 cranks, rods, pistons - which means these large journal 327's can easily be turned into a 350 with no machine work - just crank/rod/piston replacement.

 

i was told it was from a 69 truck. and its a 350 the guy i bought from was someone i trusted. is it worth building these blocks or would it be better to upgrade to an 80's and up block? what will the benifits and flaws be??

 

I'm not trying to dis you, or your friend - I'm just saying the only way to know for absolute is to get the numbers off the crank. I trust my brother with my life, as well as with my Camaro (not even my wife is allowed to drive it), and he's only human like the rest of us - if he told me I had a 350, I'd still double check BEFORE I spent a bunch of money building it.

That aside - the first order of business would be to see if there are accessory holes in the heads for your p/s pump, alternator, etc. If not, you might want to check prices from machine shop to drill & tap them for you, or get prices on heads with accessory holes before you start. I'd get the casting numbers from the heads as well, and check to see what they are, and if they're worth any effort - sometimes it's cheaper to 'pass the buck' (ie sell & find another motor) than to make something into something it's not (especially these days). Anyone in the last 40 years could have swapped heads for any reason.

Even if they're crappy smog heads from the 80's, they can still be used, although you won't set any track records. I have crappy 80's heads with large chambers (low compression), but I installed dome-top pistons to make up for it. Just remember to use short plugs when the time comes if you do this - I mistakenly installed regular plugs and on the first start my pistons mashed my plugs

Next, I'd check to see if the block has already been bored, and how much - these blocks can only handle so much boring (I think .060) - you might not want to sink your life savings into a block that's already at it's limit. And please don't bore it out anymore than it needs for cleaning purposes - boring out to the limit doesn't help gain hp - it's just a waste of a good block. People are always telling someone how much they are bored, like it's a good thing - boring out more just means you have a crappy block, or you are an idiot.

Then - as mentioned, get the machine shop to check for cracks - it would suck to spend time/money working on a bad block.

Meantime, research what parts you want to build with based on your expectations. And above all - have fun! We all want it to be "done" - but remember it's the journey, not the destination. I've been working on my Camaro for 4 years, and I feel like I haven't even begun most days. It takes patience and a thick wallet - the thinner the wallet, the more patience you need (that's me, thin wallet, thus a long time to finish - but I'm having fun, learning tons, and doing it right along the way).

 

As mentioned above, that block will work fine for your target power level, even if it is a 2 bolt main block. That same basic block was used up till 86 IIRC, in 87 they switched to the 1 piece RMS blocks and roller cams. A roller cam can get you more power and reliability than a flat-tappet cam, but is not necessary to meet your goal. Any 350 head will fit, and most if not all 305 and 327 heads should fit. The heads will determine the style of intake you need to use and ultimately the power output of the engine. I have a 3970010 block, 2 bolt main and I'm using 305(#1404416) heads on it, and they line up just fine.

If the heads are already off the block, or it didn't come with heads, you can measure the cylinder bores to determine the engine's displacement. You'll want to measure them anyhow to see if it can be bored out if it turns out to need it. Or, you could drop it off at a good machine shop and have them measure it up for you. Having the block checked for cracks/warpage/flaws is a must as well. It doesn't matter what block you use, any previously used block should be checked before the money is spent on machine work.

One last thought since no one else touched on it yet - Making a 383 is not as simple as tossing a 400 crank in a 350 block. The crank needs to have the journals turned down to fit the 350 block and the block generally needs to be clearanced to so the crank's counterweights don't hit the cylinders. You also need a cam with a smaller base circle than standard.

 

the first thing to do is as was metioned earlier is to look at the crank casting number or measure the bore size with heads off since its a budget build if its a 350 use it if not buy i newer block that is you can get them cheap once you start your build get the block checked out then get you a set of 906 or 062 vortec heads with these heads you need an eight bolt intake manifold you can get from summit for 130 or so then get a new cam and lifters like the comp cams xe 268 or if you want less cam then check out summit and you can get some good priceed kits on there from 90 with lifters and that will put you around where you want to be hope this was helpfull

 

I have a 3970010 350 block and mine has a 350 right above the the bell housing flange

 

the 350 block you have is a good block to use if it passes the pressure checks, whether its a 2 bolt or 4 bolt. if you want to run a stroker motor you can piece it together or buy a kit. You can get a stroker crank for about 200 but u do have to notch the block you also have to use a stroker piston. Its shorter and places the rod end higher into the piston. you also have to decide on the rod length you can either use your 350 rods or use the 400 rods, 350 rod will give you a little more compression b/c its longer. Or you can use the 400 rod and it will turn up a little quicker. The cam and heads are where most of your power is made it dont matter the size of the cam lift. (depending on the work you want to put in it!!) the bigger the cam the closer the rod gets to it. if you go so big such as a 630/630 solid roller( which will work) but you have to grind the rod bolts to clear (cost time and kind of a headache). head wise the vortech flows better than you old style heads. It all depends if you want to run accesorie holes. and if you run the 305 heads you will have higher compresion

 

I have used that block for many years. .030 overbore is safe. Wether it is 2 bolt or 4 bolt, you can still make a lot of power!! I would maganflux block to check for possible cracks, line hone, deck, bore and hone w/head plates. I'd suggest getting some better heads, Dart's work very well.........
Hydraulic roller w/rev kit is a good way to go,, lil pricey, but a lot of power.


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