I've come across a 305 and a 350 off marketplace, for $450 and $400 respectively (cad). The 305 runs good, it's in nice shape, (I guess it wouldn't be much of a rebuild) and the 350 needs a complete rebuild. I've been working in a shop for almost a year now, and I really wanna do a teardown and rebuild but I'm not sure what I should do. What do you guys think?

 

Honestly, both 305 and 350 crate engines are great options, but if you're looking for a bit more power and reliability, I'd go with the 350, it offers a bit more torque and is a proven workhorse, but if your budget is super tight, the 305 is still a great choice, it's just not as much of a screamer.

 

The 305 and 350 are both decent engines, but honestly, if you're looking to rebuild, I think you'd be better off with the 350 as it's a bit more widely supported and has a few more modern upgrades available. Plus, the extra 45 ponies never hurt anyone right?

 

I've been driving the 5.0L aka 305 since 1996, and have never had any complaints, but the 5.7L aka 350 is more sought after, and certainly has more power. You really don't say what year or generation these engines are, so I would consider age of both. A rebuild on a really worn out 350 might be a lot more work then a gentle rebuild of a 305 in better condition.

 

Oh yeah, my bad I completely forgot to mention. Both are from 75.

 

Well, I can tell you my personal thoughts are the 305, as if it is in really nice shape, it may need a lot less work. If the 350 is truly worn out, it is likely needing all cylinders rebored and sleeves put in, along with any number of other things. A lot more time and money. You can still take the 305 apart, but if it was better taken care of, it will likely be nicer to work with.

With the right 2 or 4 barrel carburetor and tuning, both can work really well, and if you are not worrying with all the crappy 70's era emissions control stuff, that will help performance.

Something to be aware of from my personal experience with mid 70's GM engines. They did stupid crap like put phenolic teeth on the crankshaft gear. I had a 1977 Pontiac Ventura (think Chevy Nova with a different grill and trim), which slipped timing 180 degrees one day when I parked in 1984. It was blowing gas out the top of the intake when I pulled the cover. I had to have it towed 20 miles home, and spend my July 4th holiday that week replacing the gear, and of course, everything involved in getting to it and putting it and the camshaft gear back on in unison with the chain, AND retiming everything. It was a learning experience! And thankfully, back then the local NAPA store was open on holidays. The NAPA guy offered me the same gear with phenolic teeth, or a cast iron gear. I can tell you what I went with...

If I was rebuilding an engine from that era, I would look hard at every gear, rod, bearing, rocker, valve and replace all that I could other than the block and heads.

I used to have a Motors manual that covered all domestic vehicles 1970-77. The specs pages were interesting, to see how from 1970 to 1975, the horse power on the GM 350 V8 was cut literally in half, like from 300 to 150, as they lowered compression and worked on emissions and economy.

 

I'd go with the 305, it's still a beast with the right gearing and tuning. Plus, it's gonna be way easier to find parts for and cheaper too in the long run.