Junk yard find

[clutchdust]

Don't think I did too bad today. Pulled a 350 long block out of a '90 1-ton today. Block is a 4-bolt main so that's good. But while I was there I decide that since they really don't care what engine they sell and since it had all the bosses drilled and tapped, I swapped in a roller cam from a '99 vortec in the block.

Now the cam/lifters that I just picked up will be going in my '94 Suburban that I'm rebuilding. And the 4 bolt block will get built for the Vette. So all in all, for $200 I think that was a pretty decent score.

 

[JeffP1167]

Aren't the factory 4 bolts weaker then the 2 bolts since they are not splayed caps and going straight in the 3rd and 4th bolt actually make the block weaker?

Always heard it to be better to buy a 2 bolt block and put in splayed caps over a 4 bolt.

 

[SmokinBBC]

I'd say that you did real good!

 

[mrvette]

Aren't the factory 4 bolts weaker then the 2 bolts since they are not splayed caps and going straight in the 3rd and 4th bolt actually make the block weaker?

Always heard it to be better to buy a 2 bolt block and put in splayed caps over a 4 bolt.

Heard the same for decades, but really now?? who designed the engine???

so yes, maybe stronger, but by MUCH?? I dunno, maybe if you pushing top fuel or something wilder.....

:harhar::ghost:

 

[TimAT]

Aren't the factory 4 bolts weaker then the 2 bolts since they are not splayed caps and going straight in the 3rd and 4th bolt actually make the block weaker?

Always heard it to be better to buy a 2 bolt block and put in splayed caps over a 4 bolt.

Heard the same for decades, but really now?? who designed the engine???

so yes, maybe stronger, but by MUCH?? I dunno, maybe if you pushing top fuel or something wilder.....

:harhar::ghost:

There's a little more meat in the webs of a 2 bolt block, but by the time you spend the $$$ to buy 4 bolt caps and all of the related machine work to install them and splayed bolts, you could have bought a couple of good 4 bolt blocks. And guys have been making stupid big horsepower with the GM 4 bolt blocks for a very long time.

 

[clutchdust]

Turns out it may have been an even better move than I first thought. I bought the long block for a couple reasons. I decided to pony up and buy the entire long block (+heads) rather than just the short block because the engine in the Suburban had blown both head gaskets and I was afraid one or both heads were cracked. Looks like one of the rare instances when my prognostication glasses came in handy. I took a good, hard look at the heads that came off the 'Burban this afternoon and can say with near certainty that at least one of the heads is cracked. There is a fine but noticeable line and distinct tracing where it looks like water is being sprayed in the chamber.
Now I just hope that at least two out of the other three heads are salvageable.

 

[clutchdust]

As for the factory 4 bolt debate, I thought about just having a two bolt block machined and drilled for splayed caps. But in the end, I know I'm only going to be making about 400hp with engine and a factory 4 bolt block should be able to hold that all day long. If I was seriously trying to make more than that, I might worry about the splayed caps but I'm not trying to build a monster. Just building a solid, reliable motor that will keep up with the c5 and c6s out there.

 

[SuperBuickGuy]

As my name implies, I run Buicks; 455s to be accurate; and with those motors 4 bolt would do nothing but weaken the block because GM, when they cast the motor, saved weight by reducing the amount of material in the webbing (called windowing in Buick circles). Thus, any hp level over stock GS (400 hp/500 lbs) needs, at minimum, a halo girdle to tie all the caps together.

When you're well north of that number, you have to install a girdle that ties to the rails and do a half-fill on the block.... not perfect, but it works to 900 or so hp.

With Chevrolet motors, some race blocks cam splayed - but I thought it was for the same reason as the Buick - High RPM stability. Buicks do not like keeping the crank in the block at more than 5000 rpm; I'd suspect SBC get the splayed caps for the same reason.... that said, I've put a lot of hp through SBCs and, other than ARP studs, haven't done much at all to the bottom end.

I do think that race cars - not usually drag race cars - could benefit from the stability of splayed caps; but the rest.... not so much.