Stevenmunoz

sofakingdom

iTrader: (1)

Yup, a 350 that has had the first standard-sized incremental instance of renewal / maintenance done to the block, end up with 355 CID. It's still "a 350" though, just renewed.

An engine that old is highly likely to already have had that done to it. Measure before getting all worked up over it. A 350 block starts out with the cylinders at 4.000" diameter; .030" over would obviously be 4.030". If it's already that size, it's likely not worth fooling with any further; if it's already any larger than that, you just wasted your money.

But yes, if the block gets bored, then new pistons to match the new size of the hole must be installed, and of course new rings. Rings are basically the gaskets around the outside of the pistons that seal them to the block, and just like any other gasket, if you disturb it in any manner way shape form or fashion after it's been installed, they have to be replaced. With ones that also match the new size.

As I've posted on here countless times, blocks from those years had HORRIBLE quality control. (or maybe I should say it was GREAT... they kept the quality low and rarely let it get out of control) The most common and prevalent problems include: The Starter Problem, whereby the starter bolt holes are drilled too far from the crank, and no amount of anything you can do will keep it from turning REAL slow, tearing up flex plates, and making that horrible grinding noise you can hear from half a mile away; The Lifter Bore Problem, wherein one or more lifter bores, usually toward the rear and most often on the pass side, aren't in the right place, and don't point at the cam correctly, and the cam lobes WIPE OUT no matter what you do (if the block has a cam in that is IN ANY WAY imperfect, throw the block away); The Bell Housing Dowel Problem, whereby those aren't centered on the crank centerline, so the transmission doesn't align correctly to the block, and gets destroyed; The Cylinder Alignment Problem, in which the cylinders aren't perpendicular to the crank but rather are tilted toward either the front or rear; The Deck Alignment Problem, wherein the head surfaces aren't parallel to the crank; and so forth. It's ASTOUNDING how bad some of those blocks are and still got out of the factory. Once you try to clean up some of that, it becomes obvious how foreign car makers gained such a foothold in our country's car market so fast RIGHT IMMEDIATELY after those years, and why some people will NEVER even consider buying an American car. The damage the US car companies did to their reputation lingers to this day.

Check the head casting #s. Most heads you'll find on old motors are GARBAGE, specifically, they're the reason why 70s 350s had as little as 160 HP. How pitiful does it get anyway. And the HEADS are the primary first and foremost reason why. Do not even bother attempting to build a motor that's supposed to be "fun" with inferior heads, they will defeat you every time.

Next time, come ask this kind of question, starting out with whether you should buy some thing AT ALL in the first place, BEFORE buying it, not after. Let's hope you didn't just make an installment payment on the Dumba$$ Tax. I can't tell you how many of those I've made over the years, long since lost count, and they're don't get any more enjoyable as time goes on.

AlkyIROC

A 350 bored 0.030" over makes 355 CID. It is not a stroker, just a standard rebuilt overbore. Stroker means you're increasing the stroke of the piston by changing the amount of stroke is made by the crankshaft. Using the longer stroke of a 400 crankshaft, a 0.030" overbore becomes a 383. There's a lot more involved than just finding and using an old 400 crank.

With any overbore, pistons need to be matched to the new bore so buy your pistons before taking the block to the machine shop to be bored out. Wrist pins are pressed into the rods. The average person can not easily swap the pistons over. There's a good chance of damaging something.

As nice as it sounds to "make it your own" there's a lot to building an engine properly. You can just assemble a bunch of random parts and expect it to last. In the end, it's probably easier and cheaper to just buy a stock replacement engine from GM or any local parts supplier then do some modifications like a cam and intake swap to make it better. The only way to rebuild an old engine cheaply is if you have the knowledge and equipment to do all the machine work yourself.

A cheap rebuild for yourself is to leave the bore alone. Unless you have a bore gauge, you won't know when kind of condition the bores are in anyway. You can run a ball hone through the cylinders to deglaze them. Use the original pistons (keeping them in the original holes) and put new rings on them. Put new bearings and gaskets in the engine. That's a basic cheap rebuild. Once you start doing things where machine shop work is involved it starts getting more expensive and in the end, a replacement engine is always a cheaper option.

skinny z

A question regarding this statement: (and I hope the OP doesn't mind the thread hijack)
Is this issue in any way responsible for a hydraulic lifter (or lifters) not being filled thereby preventing a proper adjustment?
The reason I ask is that this particular problem (one noisy lifter on cylinder number 6) occurred in one of these vintage blocks, (circa late 70's "010" casting) and no matter what I tried, up to and including changing lifters, the noise persisted. I should add that this happened sometime after the cam fuel pump lobe had completely worn away (for reasons I never could determine) and the engine was filled with cast iron debris. My take on it was this greatly accelerated the lifter bore wear resulting in that lifter not receiving adequate oil pressure. Up to the point of the lobe failure, the engine performed flawlessly.
The Lifter Bore Problem as described above leads me to think in another direction.

sofakingdom

iTrader: (1)

The lifter bores intersect a passage, about ˝" dia, from front to rear of the block. The 3 plugs around the cam tunnel plug them: the one on top is for the cam main & rod bearings, the 2 on the sides go through the lifter bores. Therefore there's NEVER really an issue with the lifters not getting enough oil fed to them.

Or perhaps I should say, only rarely... the passage isn't drilled all the way through from one end to the other, rather, halfway from each end, only meeting in the middle. I recall one 70s block somebody brought me to build for them once... I unscrewed the plugs from the back, then went to stick a Ľ" rod I had, into the passage to knock out the front ones. It stopped halfway and I couldn't get it any further. Turns out, the front drilling and the rear one, MISSED by SO MUCH, that the Ľ" rod wouldn't pass. After further inquiries I discovered that every motor that had been built into that block, which by that time was a couple by the present owner and at least one by the previous, had experienced "unexplained" failure of one or more of the front 2 main or front 3 rod bearings. Hmmmmm... I thought I just found the explanation... so yeah, I guess that's ANOTHER QC Problem that can be added to the other Problems I mentioned.

Sounds like in your case that one lifter bore was misaligned. And, like, OMG, it's one of the rear ones on the pass side. Who woulda thought... Most likely the noise wasn't rocker adjustment; more likely, it was the lobe and lifter face complaining, due to their poor contact. Can't say I've ever seen a FP drive rod passage mis-drilled myself, but since EVERY OTHER machining step in blocks from those years was subject to random fornication, and I've seen some that I would never have thought possible, wouldn't surprise me if yours had that.

I recall one I got brought that the owner had complained he could NEVER get the intake to seal, and had even broke one intake trying to tighten it down enough to get it to quit leaking. Turns out, in that one, one of the head dowels was a good 1/8" too far to the outside, which in turn, cocked the head at a weird angle, making the intake flange gap 1/8" wider at the front than the back or whichever way it was. Needless to say I declined to build him a motor until he brought me another block, just like I had to make the guy do with the one with the Oil Passage Problem.

Like I said, how many different ways are there that the factory could have BLATANTLY EFFFFED UP a block, and shipped it ANYWAY? I got tired of blaming it on "Friday afternoon" after it started seeming more like the rule than the exception. I think when I was building lots of motors for racers (early 80s to mid 90s) I don't think I ever saw EVEN ONE block that didn't have some sort of defect like that, once I started actually looking closely at them.

NoEmissions84TA

iTrader: (1)

Sofa is correct. I have one of those blocks. It was never installed in a car, so no numbers stamped on the PASS cylinder deck.
It was bought "over the counter" in 1988 (not a roller cam block). This block has the lifter bore problem. The easy way to tell is to check if your pushrods spin as the engine is running. Actually, just rotating the crankshaft will allow you to watch this happen. The rotation happens on the closing ramp of the cam lobe. I paint a line along the length of the pushrods with a paint marker to make it easy to see. If the pushrods spin, then the lifters are rotating. Flat tappet camshafts must have the lifters rotate. No rotation equals a rapid death and metal shrapnel throughout the engine.

Stevenmunoz

NoEmissions84TA

iTrader: (1)

The only way to know for sure is to take it apart and have a good machine shop check it out.
Then it is possible that you find out that the block is junk for some reason and you have just
spent even more money with nothing to show for it. Sadly, it happens. Good luck.

GeneralDisorder

iTrader: (1)

Honestly it's not even worth messing with. Get a 96 to 99 Vortec engine. They are very cheap and don't have the machining problems that the 70's stuff had. I got a nice condition pull-out with oil/water mixing for $200. Was perfect inside other than being full of milkshake from the failed plastic intake gaskets.

You might pay a bit more, but you get powdered metal rods, Vortec heads, and they are hydraulic roller blocks - just the hydraulic roller cam setup is good for 50+ HP with a good cam. The Vortec heads are essentially LT1 Corvette heads but in cast iron.

That 70's engine isn't even worth the risk. Sell it to someone else that digs on antique dump truck engines. Don't put it in your sports car. Farm implements tend to be heavily abused and they do a lot of idling. It may have 60k but it may have twice or three times the hours that a passenger car engine would have. Engines that are used in heavy duty applications like farm trucks or RV's usually live a short life. Often they are all done by 50-100k.

What is your budget? Just machine work on a used block may easily run over $1k.

GD

sofakingdom

iTrader: (1)

^^^ This ... ^^^

One of the things a first-timer doesn't realize is, that there's no "cheeeeep" way to "rebuild" a motor and expect it to live, be happy, not smoke, make good power, not leak, and so forth. And that the CORE, the old wore-out used-up thing you're going to have to POUR MONEY into, isn't the part that costs the most, or even remotely close to it; but it determines the chances of success more than any other. You're going to be taking a $150 (or whatever) core, putting $1k of machine work into it, buying pistons, rings, bearings, cam, and whatever all else to add to it, but if it's a POS to begin with, all the rest of that money is WASTED on it.

Think of the block as being like the foundation of a house. If it's made out of quicksand, then it doesn't matter if the house has gold-plated toilet seats, marble hallways, exotic wood trim, and any other "upgrades"; it's STILL going to be a falling-down worthless POS. Granted, the foundation of a house isn't "sexy", "glamorous", "exciting", or any of that; no prospective buyer's 8-yr-old kid is going to ooooh and aaaaah all over it like they will over chrome hardware; but all the eye candy you can slap onto a house built on quicksand, is WORTHLESS, just lipstick on a pig. Building an engine is EXACTLY the same. All the race-car parts, "heavy duty" this and "best of" that and "forged" the other, is WORTHLESS if the damn thing won't start because the starter is too far away from the crank for the teeth to mesh or if it has some other UNREPAIRABLE PERMANENT FOREVER machine work or casting Problems built into it.

At this point in history, the ONLY small block Chevy to build is the 96-2000 350. Don't even bother with that old crap. It will bite you in the butt, and you won't even be able to know it until it's TOO LATE and your wallet has already been emptied on it. You've heard Murphy's Law no doubt: it says, whatever can go wrong, will. Well in my experience, Murphy was an optimist. The REAL WORLD law is Sofa's Law, which says that if anything can go wrong, it already has, you just haven't found out about it yet, and it's already too late to do anything about it. Try to stay away from taking that kind of risk... minimize opportunities for things to go wrong that you can't know about until it's already too late to do anything to avoid them.

GeneralDisorder

iTrader: (1)

To give an idea - the machine work on my 99 Vortec block (really good condition mind), which included hot-tank, turn crank 10 thou, align hone to match Clevite bearing set, surface decks, very light bore cleanup, new rod bush's, resize rods for ARP bolts, install cam bearings, install block plugs, and seal all oil galleries..... and he gave the block a coat of primer for me. All this cost me about $1250 (that's including the ARP bolts, mains, rods, and labor) - and that's a cash discount for a frequent wholesale customer (me) because I'm building this engine for business advertising use. For VERY LITTLE more you could just buy a crate motor complete. Trust us - it costs a LOT to do this yourself. And to do it right you will be looking at around $2,000 just in tools - not to mention the learning curve - which is pretty involved even for someone like myself that has a lot of engine building experience - just not on the SBC specifically.

I disassembled a (free) 89 3/4 ton truck SBC prior to getting the vortec. It wasn't worth messing with. And it only had 100k on it. The cooling jackets were a rusted mess and my attempt at removing the rust from it wasn't successful. The Vortec engines ran Dex-Cool, and while it caused some problems for GM, it lasted a long time and my cooling jackets on my Vortec are PRISTENE. If you plan to build a high performance engine - that last thing you want is a compromised cooling system due to excessive jacket rust or even cracks in the weakened, thin block....

GD

midias

Keep an Eye on the L31R crate motor they regularly go on sale for $1700 with free shipping. Nice roller block good vortec heads. Do a cam swap and a spring swap on the heads. After the cost of getting a used engine and machine work you are not far off.

https://www.jegs.com/i/Chevrolet-Per...30283/10002/-1

skinny z

My old auto shop teacher (who, incidentally, literally WROTE the book for high school auto mechanics back then), used Murphy's Law as an example for those of us who had optimism mixed with inexperience and an added dash of naivete.
Sofa's Law would have been appreciated by him I'm sure.
R.I.P. Frederick C Nash (look it up).