I need to post pics of what my dads 350 vortec did at 6:00 pm tonight. Crank the engine over and CLANK, CLANK, CLANK, Starts running on 6 cylinders or so. Kill the engine immediately, look underneath. Oil is everywhere, coming from 4 small holes in the pan. Open the radiator cap and coolant pours out. Thats right connecting rod failure on an easy driven 57,000 mile 1997 350 vortec. It has had the oil religiously changed at 3,000 miles too. Now you know why I dislike 350s.

haha that sucks but why did you open the radiator cap? that was just dumb and doesnt prove anything.

My dad did it. By the way the engine was cold, it had been sitting about a week. He wanted to see if oil had mixed with the coolant and it had.

"Now you know why I dislike 350s."

Yeah...and I heard that 350s were supporting the Taliban rebels too...

What? Obviously the 350 is a well-designed engine... I would think that the intake gasket failed (notorious cheap *** GM gaskets) and coolant mixed with the oil, which killed the bearings.

This is a GM problem, not a 350 issue...or they wouldn't have been building them from the late 60's until 1999 (Tahoes/Vans)

I fail to see how this is a 350 specific problem in anything but the mind of a hopeless fanboy.

A buddy of mine works at a GM dealership and he said that the vortec 350's are notorious for throwing rods. Why I dont know, but he said that there is always a truck or SUV in there getting a ew vortec motor put in. I also think that is one of the reason it is so easy to find a set of used vortec heads, because after these guys blow the motors they sell the heads.

Well...using "Fast305" type logic...here we go:

The guy at my local GM dealership is a total retard, overfilled my truck's transmission doing a simple fluid change.

Therefore, guys at GM dealerships are retards. Your buddy works at a GM dealership, so...

OK, oxymoron man ("Fast" "305"):

Have you looked at the part # on that crank? Before you do, and show yourself what a foolish thing you just said, I'll give you a clue about something: 85-back 305 & 350 cranks are the same casting!!! There's no difference except balancing. Same for the rods. I'm not sure about the later 1-piece cranks, but if I know manufacturing in general, they'll be just like th e85-back ones. In other words, that 350 has the same unreliable crank and rods as a 305 of the same year, by part number.

So how is it that a motor whose block has a 4" bore diameter is inferior to a motor that is otherwise identical except its bore diameter is 3.736"????

Please help us all to undertand how that extra quarter-inch of bore makes the 350 a poorer motor than its later designed scaled-back little stepbrother.

"It's better to merely be thought a fool than to open your mouth and remove all doubt".
- someone much older than me, and wise besides, which is something I lay no claim to

not a bad design.

builder/operator error.


theres 1000s (heck 100,000s) of SBCs running fine. the only variable in yours is... well you.


lol, we're all jumpin on your *** because well... you're calling what is possibly the most reliable mass produced V8 ever made, unreliable...

same basic design since the late 50s until present has been made... simply because it works well. i think you're better off finding where YOUR engine was foobared then you are just calling the whole design scrap.

Why do you guys waste your time with such easy pickings. This guy obviously has limited experience with these engines. Let him be. Anyone who's anyone knows what a dumb statement this is. Not trying to be fussy, just wish more people would move on to technical stuff. RB83 and MrDude, you guys are obviously very very experienced and smart, so why so mean. Share some of that technical knowledge. Yeah, and I know the flames are coming. So I guess i'll just duck for now. :lala:

everything i posted, i said with a smile

re-read it with a friendly chuckle and you'll see i wasnt being mean... i even explained why everyone else jumped on his butt.

Sorry, I just couldn't help it. This guy is too funny to pass up an opportunity for a little humor.

So, to keep it tech, I guess I'll just agree that 350s are all junk, especially the Vortec ones, which is of course what makes everyone in the world not want those and instead makes 305s the highly prized and sought-after motor, that you always see winning at the races and stuff.

I often wonder if the "Hecho en Mexico" engines are the ones that fail the most often. These blocks are rumored to have very thin casting walls. So thin that .030 overbore has rumored to break through the cylinder walls.

I'm not saying that a 350 is a bad motor. I am just saying the 2 that I have had, had defects. Its funny how the 305s that we have had last much longer than the 350s. This is just my observation.

If 350 vortec short-blocks don't die early, why do you think there are so many vortec heads on Ebay all the time. The rod bearings failed, the rods broke, etc so they sell the heads.

It probably isn't a 350 specific problem. I think it was poor quality control. I know that the 305 and 350 share most of the same parts. The 350 rods and crank maybe the same casting but it will be more durable in the 305 because they are under less stress. Usually the 305s block is thicker too. Both are sound engines. I just think someone got lazy on these last 2. Both were manufactured after 1996. I have no complaints with my early 80s 305s. If the 350 had been built to 1980s quality I probably wouldn't be sitting with holes in my oil pan.

Limited experience??? You guys must be crazy. We have had 2 305s go a combined 1/2 million miles and are still going. Knocking on wood.

Instead of poking at the fact that I find 305s plentiful, cheap, economical to operate, particularly durable and more than adequate in the power department, help me figure out why this engine croaked so early. I am thinking that the intake gasket leaked. I didn't know that hydraulic lock would do this much damage. I thought at worst it might bend a rod or break a ring. That is why I am thinking that GM didn't torque the rod bolts tight enough. The pan is windowed right were the rods of cylinders 3 and 4 meet the crank. I think the #3 rod let go, further disproving the intake gasket theory. I guess the head gasket could have leaked. My dad told me it cranked over real slow one time, the made a huge bang, then it started and the clanking began. He shut it off immediately, but the pan already had holes in it and coolant was pouring out with the oil. That means the block is probably trash. Unless the piston came out of the bore and it had coolant above it. For simplicity let assume the block is internally windowed. If so the cam is probably damaged. I have a roller cam 350 TBI shortblock with 20,000 miles on it. Is it interchangeablly the same block as the vortec? If so I can stick the Lt1 roller cam(sitting in my garage) in it, vortec lifters and retainer spyder, add a new vortec timing chain(crank sprocket has a wheel for a crank position sensor), vortec timing cover, vortec heads, vortec intake, and the vortec accessories. Drop it into his van and he will be on the road again.

i stand by my orignal statement of user error on that one. i mean im not saying you're a bad user. I am just saying the 2 that you have had, had failed. Its funny how the 100,000 that we have had last much longer than yours. This is just my observation.

(same logic see my point? )




no offence, but this is a Really REALLY stupid statement.
the reason that everyone is ga-ga over the vortec heads is price. new ones are still being made by GM, and the over-the-counter GM price is really low. several years ago, a popular performance mag let the general public know about how good these cheap heads were... since then people have gone nuts over them. guys like me can get the cheap from lots of places.. some like to toss them on ebay because there are a bunch of suckers out there that think $500+shipping on a set of vortecs is some kind of deal.


possibly, but highly doubtful. as far as engine assembly, GM is amoung the best.. its kinda hard to fug up a SBC really... tolerances are huge and the parts are way understressed. i still think somthing else went wrong.
what did he do before it misfired with a big bang? by anychance did he flood (hydro-lock) it?

true. they dont make **** for power. so they dont stress them as much... then again a stock SBC 350 will go over 150,000 miles without issue... 200-300 if you take excelent care of it.


nope


lmao.. if it was 80s quality, it would have smogger heads,tiny cam, and make 180hp...
of course 80s motors last forever... the damn things are so underpowered that they dont wear anything out but the valveseals.

and if they did blow, it really wouldnt have enough power to go thru the oil pan.. lol

i would def call that limited experience. i mean, you just quoted miles when we're talking about working on cars.
you could drive a billion miles, doesnt make you a mechanic.





my guess... if the intake gasket leaked or possibly if it just got too much gas, it hydrolocked the motor, and the stress from that blew it apart.... then again, i didnt take it apart and look at it, so its a wild guess.



ok, down to the real responce..

yes its the same block. just be sure to have the correct flexplate/flywheel for the crank.. depending on if its one piece rear main or two. the top end will bolt right on.
i dont know what the compression will be though. might want to look into that.

other then that, yea that sounds like a workable plan. go for it.

As far as mechanic skills. I rebuilt the last 350 that died and it now has 50,000 miles on it. I rebuilt the 307 in my grandfathers 1988 cadillac(had 220,000 miles). It is still going strong. I cammed my 305 and rebuilt the heads. I am going to build this 350. I just rebuilt a 700r4 over my spring break. Before that I did a 3 spd stick. I have done several A/C rebuilds. Changed many engine accessories (numerous starters, alternators, compressors, P/S pumps, etc.). I have done carbs for many people including myself. I do work for other people all the time. What I meant by the 1/2 million mile mark, is that my dad has had experience in this and I have too. The failure was not because of the operator or lack of maintanence. I just rebuilt a mazda 2.0 for my little brothers mazda truck. Call me mechanics illiterate if you want, its your decision.

As far as the ebay thing. I have seen many used vortec heads on there. Many owners claiming other engine problems are the reason they are selling the heads.

You are right about 1980s engines being understressed. That makes them LAST FOREVER. You claim they are underpowered. They don't run 13-14 second quartermiles. So what. 180 HP is enough to move anything down the road, way over the speed limit.

I am glad to see this thread actually generated something useful. Luckily I can use the TBI shortblock and it will get the job done. I just looked up the compression. With 76 cc heads the HD 3/4 ton 350 tbi had 8.4:1 compression. If I use the vortec heads it will give me roughly 9.6:1 compression. Only 0.2:1 above the factory vortec.

305's suck.

Either Abe Lincoln or Samuel L. Clemens. Seems to be some debate on that.

Fast 305, if you were stepping up and wanted to sell your old heads, would you say that in your sales pitch that you are using trying to convince someone to buy 'em? ex:

<b>These Vortecs suck for big power on big cubes! Please buy and subsidize my AFR's!!!</b>

See what I mean, really makes you want to buy 'em no?

2 of our nation's most famous humorists.... and both rather wise men as well.

hold on a minute you tryin to say that a 305 is not under as much stress as a 350 man you got some learnin to do ...lol...how hard do people over rev a stock 305 to try and keep up with a 350 ..?????....LMAO

I think what he means is that 305's arent under as much stress because they are the biggest dogs in the world. Unless, that is you have a 1980 smog 305. These are the fastest of the fast. THey also have walls so thick you can bore them .100. Best engines ever made. </sarcasm>

i think that the guy that started this thread was just lookin for someone to say no there is something wrong with this engine not with the way you drive..LMAO....and i dont think hes gonna get that here

I think there is some truth to what he is saying about the vortec motors because I have seen them on Ebay saying the motor blew something on the bottom end so they are selling the heads, but my dad has a 350 TBI in a truck that has 195000 miles no problems except transmission, my GTA has 104000 miles no problems either, these are newer engines so there is bound to be a few problems

opinions are like a$$holes everyone has one and they all stink so I hope all the whining made all of you feel better

Enough is enough.

You know what you need to do to get it running again. The rest of this goes beyond the Board rules and you all know it.