Every now-and-then I hear about late-model, 1pc, block castings being junk...save for a few. Now I have just spent a lots on rebuilding my motor, based from my 350 TPI block (casting 638) and I would like some input about these rumors. I had the block to the machine shop where all the tricks were performed: tanked, magged, line-honed, bored w/ plate, decked; will the fact that it's blueprinted help? Anybody here run a healthy motor from one of these blocks?

Any input would be appreciated!

Thanks

 

only stories i ever heard were about mexican blocks and blocks from the 70s.

 

The '87 block I had was messed up 3 cracks in the lifter valley, I was told by the shop that was common. Ended up with a '91 block he had.

 

lifter valley cracks aren't uncommon for any year block

 

Well this puts me at ease a bit. Maybe its the 87 blocks that suck...my buddy had his 350 built up in his 87 IROC and his block took a major **** too (8-inch crack up the side of it )

Thanks guys

 

I've never heard anything about 86-up blocks having any special problems.

There's ALOT of people on this board and elsewhere running all sorts of things with 638 blocks; nitrous, blowers, stokers, etc.

Lifter valley cracks are usually the result of freezing. You can't really blame that on the block.

Like ede said, 70s blocks have issues, namely quality control problems; but that's about it.

I'd say if you've had yours magnafluxed and no cracks showed up, then you've got as good a one as any. Don't worry about it. "Blueprinting" makes no difference to the casting integrity of the block; except that somebody has actually paid some attention to it while macjining on it, so if there was a problem, they'd be more likely to notice it than some slap-together kind of builder.

 

When i had the 350 in my 88 iroc replaced in 1993 under the factory five year warranty the dealership manager told me the truck engines had major cracking problems from 86 thru 88. Since the iroc 350s are truck engines not corvette L98s they also had the cracking problems in lifter valley. My engine cracked on both sides just above the lifter bores almost the full length of the block.No leaking was visible but it was clearly cracked. I originally took it in for an external antifreeze leak around the intake, when they removed the intake they found the cracks.

 

Hmm...I like what RB said but i didn't want to head what 884 had to say

I guess only time will tell...thanks again for the input,
Nick

 

There was a recall way back when for some blocks that would crack between a coolant passage and an oil gallery(pass side i believe) but most of those blew up before the 40k mark.

 

What the hell are people smoking lately?!? If anything, some of the truck blocks from 86-88 were the older castings, but most were still four bolt. The latter casting which had provisions were also mainly 4 bolt blocks. What L-98's came 4 bolt? And how are the iroc engines truck engines? I don't recall any trucks coming with a tuned port sitting up top. WTF?!

RB has already explained the why (in all likelyhood) for cracks in the valley.

What IROC_385Z is probably hearing are confused/ignorant/stupid people that can't tell a Chubby from a Fjord. The '85 (IIRC) up roller blocks of ford 302's have a tendancy to split (yea, SPLIT) if you tweak 'em too much. Chevy may have had a recall, but I don't beleive it was so severe that it would float around like this for this long.

 

Yup, Ford 302's love to just split in half right up the middle. I've seen 3 in person, and have heard of lots of others...

 

When I had the motor in my 'bird redone, it ended up getting 2 cracks in the lifter valley. I was told also this wasn't completely out of the ordinary for the 305's (don't know if that was exclusive or not). So, I bought a new/improved block from the dealer and so far, so good.

 

Ya know thats true...alot of 80s trucks prolly did have 4-bolt blocks. I'm pretty damn sure that the TPI vets had 4-bolt blocks...but I think that the IROC 2-bolt blocks were shared in some light-duty GM pickups and vans.

All in all, the block has over 100k on it (well seasoned I guess), has passed the machine-shop inspection (im counting on you Yoe) and is blueprinted...I choose to not be paranoid and believe that it will be OK .

Thanks for your inputs all!!

 

All vettes didnt get 4 bolt mains either, common misconception

 

From 87 to 91 there were problems with the lifter galley cracking. for some reason most of the ones we replaced in my dealer were in trucks,but then again we sold more trucks. I have owned several cars and trucks in that year range and never had a problem personally. Luck of the draw I guess.