what are the differances and measurements between the 302, 327, and 350?
and is stroke measured between center of main and center of rod?

see if anybody knows these block #'s 3970010, 06u214972, v0712tyu?

 

Bore is the same for all 3; 4.000".

Stroke is different; 3.00" for 302, 3.25" for 327, 3.48" for 350. All 3 used the same length rods. So they all have different pistons, with the wrist pin located at a different height.

There are 2 different journal diameters for SBCs of those sizes (400 is yet another); 68-back is small journal, 69-up is large journal. So there's more differences than just bore, among blocks for those sizes of motors.

The 3970010 block is an extremely common large-journal block from 69 up through the late 70s sometime. Nothing special in any manner way shape or form. That same casting # was used to build motors of those 3 sizes from, which is why you find it listed that way.

06u214972 is the last digits of the VIN of the vehicle the engine was installed in. Tells little or nothing about the engine itself. Altogether worthless.

v0712tyu is the plant code for the engine. It tells what type of vehicle it was for, what heads it had, what CR, what HP it was "rated" at, what plant the engine was built at, etc. Altogether worthless unless you have a KNOWN COMPLETE ORIGINAL motor. If the motor has been touched, it's worthless. It tells nothing about what's in the motor NOW, TODAY. V means it was the Flint MI plant; without looking up that whole #, probably a pass car motor.

Yes the stroke is measured from the center of the main journal of the crank, to the center of the rod pin.

Probably 99% of those blocks were originally in 350s; 0.999999% in 327s; and ALL those vast numbers of others remaining, were 302s. Unless you have the original crank that came with the motor, none of that makes an difference now; it's a block.

 

yeah I got all but the intake. I am only useing the block, crank and rods. I was just wondering cause the place that did the mechineing wanted the block. so I just was hopeing to find out why and if I could make some cash and just build my other 350 which is only a 2 bolt as opposed to a 4 bolt.

is there a way to find out from the crank..........I mean jurnal to jurnal I only got 2" so I figured that wrong

 

Casting or forging #....

If it ends in 442 it's a 350

Only reason they'd want it, is if it's a 4-bolt; they'll be watching for the "greater fool" that thinks there's some kind of benefit to that, and is willing to pay mega$$$$ to get it. Don't laugh, they're out there.... lots of them.

 

hell I only paid 100 for the long block. never took of the pan before he sold it.......

 

So what your saying is that 4 bolt main is a waste of money and no advantage over a 2 bolt main? Just making sure im reading that correctly.

 

Yup, that's pretty much what I'm saying.

A factory 4-bolt block is meant to deal with one particular kind of stress; that being, what a truck in non-highway use puts on it. More or less continuous operation under high load but not particularly high RPM. The factory setup is not particularly effective under racing conditions. People get stars all in their eyes about it though, kind of like if you attach the word "Vette" to something.... like, "I've got a Vette starter, so why will my car still not start?" or "How much HP am I making? I've got a Vette block" or whatever, when the "Vette" thing itself, is indistinguishable in any way from any other. As if, magical pixie dust was in the fiberglass and sprinkled itself all over the casting and now the casting is inherently superior somehow. Yeah right. So I've seen ALOT of people over the years pay like 5 times what they would for a block with 2-bolt caps, to get one with 4-bolt caps on it; even when the extra 2 bolts made no improvement whatsoever in their finished product. All they did was to make their car slightly faster by way of a weight reduction centered on the driver's wallet.

The strongest arrangement for a stock block is a factory 2-bolt block, with billet main caps installed on it using splayed outer bolts. A factory 4-bolt block will work for that but already has these extra holes in awkward places.

And then of course, there's the "400 4-bolt" situation, where the early 400 blocks (which all have 4-bolt main caps installed on them) have thin metal all around the main webbing, but the later ones (which all got 2-bolt caps) have thicker metal, so people try to somehow equate the lack of metal with the number of bolts. That's a real common confusion. There, the 2-bolt block is DEFINITELY better than the 4-bolt; but not BECAUSE OF the number of bolts. It's not like the bolts are what hurts the block. You just use the number of bolts to identify whether it's an early or a later block.

 

so wait.....what your saying in turn is a 4-bolt'll come apart before a factory 2-bolt? well mybe I should build my 2-bolt then? and not save my 2-bolt for the splayed caps and a charger+nitrous?......


I mean I want my 4-bolt for a 400 to 500hp daily and my 2 bolt for a about 800hp weekend car

 

If you want something strong get a 2bolt block and put splayed 4bolt caps in it, alot stronger than a factory 4bolt...

 

No, now that's not what I said. Let's not be putting words into my mouth.

What I said is, factory 4-bolt caps on the center 3 main journals of a 350 block such as a 3970010 casting, are not a particularly effective upgrade for a racing build. And especially not if you have to pay extra to get them.

At no time did I say that they're "worse" than 2-bolt caps. The extra bolts don't "weaken" anything, or anything like that.

Keep in mind, the block casting itself, is IDENTICAL IN EVERY WAY, regardless of whether 2-bolt or 4-bolt caps were installed on it later on in the engine assembly process.

 

ok, you had me confused there for a min......but a stock 4-bolt will handle a stupid driver better then a 2