305 vs 350 durability

[Old Blue]

I've heard conflicting answers from people regarding the durability of the 305 V8. Next spring I'll be towing about 6,000 lbs with my '99 K1500 w/ a 305. I know that keeping it in 3rd gear will help save the 4l60e, and doing so will keep the engine at 3k RPMs. I've read on here that 350s will run like that for hours on end, but nothing has been said about the 305. Are they built just as strong? One person I've talked to said GM used a different crankshaft that isn't as strong in the 305. It's a re-manufactured engine and only has 28,000 miles on it.

 

[98 Nitro]

Vortec 305s are good engines and built as good as 350s in a 1500. Now the 2500 hd/3500 series 350s have 4 bolt mains and I think a stronger crank.

 

[DerekTheGreat]

Really the only difference between the 305 and 350 is bore size. One of those will run just as long as a tree-fiddy. If it's bone stock I wouldn't even think about the crankshaft...

 

[retorq]

The crankshaft is different due to the less mass needed for balancing. You can't use a 305 crank in 350 or vice versa without machine work.

 

[TylerZ281500]

^ sure you can, you have to rebalance it. just the argument 2 bolt vs 4 bolt, guess what folks really no difference. ive made a fortune off the idiots who think 4 bolt main blocks are worth more. 2 bolt you can at least splay, but at the end of the day it comes down to how balanced something is. cranks straight out the plant are the exact same cast, exact same machining, different balancing, as is 350-350.

the rest is mostly personal opinion and some scientific data to back things up. 350 has more displacement, more displacement means more air more air means somewhat more power (vaguely)

strip both motors down and the difference is bore size.

we could argue even that the 305 could be better at long term RPM because less rotational mass, unfrotunately comes down to engine balance once again.

for towing.......id look into gearing, youll benefit very little swapping engines, also with a 60e heat is the enemy, get a big cooler, magnefine filter and a few externals and shell live to be older than your grandma

 

[Rock Hard Concrete]

Relative piston speed is the same due to same stroke. One could say that the larger bore spreads the combustion over a larger surface area improving long term durability.

I'm sure some autist will chime in and say I am dead wrong but ask anybody where I'm from and they'd say the 350 is a much stronger longer lasting engine. I seem to remember hearing something about the top ends having issues in 305's as well; could be wrong don't quote me.

I'd take a 4.3 v6 vs over the 305 v8 any day not giving a **** about tq or hp output.

 

[TylerZ281500]

all the same materials guys, vortec 350s were probably worn, heads more prone to cracking if you wanted to go that far into it.

 

[Tom P]

Engine durability is a tricky deal IMO. I know guys that maintain their stuff meticulously and use OEM parts and fluids that have had issues, and then turn around and see some people beat the living s__ out of their stuff and it takes everything that gets thrown at them and runs for 300K miles on the same set of spark plugs. We had a customer who put a cummins factory reman 5.9L in his Hesston Grass Swather.... the engine lasted 93 hours before it spun the front main bearing. Cummins tore the engine down and admitted to it being a faulty factory rebuild. Front main cap never got torqued properly. That engine was probably built on a monday morning or friday afternoon. I don't think there is a simple answer to your question because there are an infinite number of variables, but all these guys bring up good points.

 

[redfishsc]

305's are reliable just like their 350 counterpart. I will restrain myself from criticizing the motor for being a completely unnecessary option that should have never been offered, that gets a good deal less power than a 350 and sometimes gets even worse gas mileage. I won't say anything like that at all

 

[DerekTheGreat]

Yeah I agree, the 305 should have never been offered but I see it as a way for GM to get more money for the "uplevel" 350 option.