5-0 Blackbird

Now before you say, "oh another one of these which one threads" I really need some help making a decision on what engine to use in my Firebird (I have researched). The weather is decent so I'd like to start working on the motor issue with the car so I can get it on the road. Now I'm stuck between using motor choice #1 which would be an average older Chevy 350 (70's early 80's) or motor choice #2 which would be a 96+ Vortec 350. Now, with the older Chevy motor I could swap my Edlebrock Performer intake manifold, Holley carb, and the mild (off-brand) cam from the bad motor in the car now. However, I've read up on the Vortec 350 and it seems to be nice, being a roller motor and already having Vortec heads. My question is, which would be better performance wise? assuming the Vortec would be stock for now besides my Holley and an intake manifold (unless I can make money by selling the unuseable parts from the old engine) and the older 350 would have the parts mentioned above from my old motor. I wouldn't be asking for help if it wasn't for the fact that I can't make a solid decision, I'm wasting a lot of time researching one then switching back to the other (even though I'm leaning towards the Vortec right now), I'm not getting anywhere, lol. So pretty much which idea would yield better results for now/ the long run for performance? Obviously I would dig more into mods later, but this is just to get the car up and rolling. Sorry for the novel! Thanks for any help/ opinions.

Atilla the Fun

The older 350 isn't going to reach 400 horses without changing heads. The vortec 350 only needs the GM "HOT" cam kit, an RPM AirGap intake, and headers to see 401 HP @ 5600 rpm and 428 ft-lbs @ 4200. The older 350 won't see 400 ft-lbs without changing heads.

5-0 Blackbird

So sounds like a vote for Vortec. I've been lookin around for one, no luck yet, but I think the extra effort for the Vortec seems worth it. I thought about it last night and I figure even with the cam and intake on the older 350, the Vortec would still be making more power stock. My grandfather has a 97' K1500 4x4 with the Vortec 350 and the 5 speed (almost 170,000 miles) and that thing seems like it has no problem pulling the truck in any gear. Anyways, thanks for the reply Atilla.

Atilla the Fun

You can do just as well using the older short-block with Vortec heads, the main drawbacks are that: (1) Usually carbureted engines show far higher bore wear per mile than EFI engines, (2) you don't get the provisions for the factory GM style of hydraulic roller lifters, (3) you can get a complete used engine for about the same money as a pair of new heads. Tra AA Midwest and EngineQuest. Maybe even LKQcorp If you can get the older block and rods for under $150, and it needs overbored, you may as well just do a 383. With dished pistons. At least 18cc.

5-0 Blackbird

That's exactly why I asked this question on here (and I know this question is getting old and that's probably why you're the only one replying). I think I have my mind made up, but then you think about it more and find different advantages and disadvantages to each. Right now, I just want to get the car up and going as cheap as possible, which in my mind, means trying to avoid the need for a machine shop. The current engine in the car needs main/ rod bearings I believe and I figure might as well replace the crank as a precaution, but I heard that I should have the engine balanced with the new crank. I have no clue how much a balance goes for, I saw on a magazine's build up a balance cost $150. Idk I'm lost dude, lol. So it's not really that I'm a newb who doesn't know anything, I just can't make a choice. Anyways, thanks for the help so far Atilla.

Atilla the Fun

I didn't realize money was tight. That changes things.
As to noone else replying, it's been my experience that that means they don't strongly disagree with what's already been posted. That or they really aren't certain, which is also okay.
As money is an isue, first lets get back to the basics.
1) are you still driving the car? (2) if not, is the engine apart? (3) If not, what makes you think the bearings are toast?

5-0 Blackbird

1) no, the car is off the road, only ran it maybe twice at like 2-3 mins a run (2) nope, engine is completely together and actually runs great besides the knock and needing the carb tuned (3) I asked a couple people (took a vid of it running also) and a few said it might be the rod bearings, but from what I have heard personally rod bearings usually sound like a sewing machine or close to that. This knock is deep and solid, sounds like the exhaust is hitting the floor board (which is what others suggested), but the exhaust is solid. I didn't hear any knock when we loaded it on the dolly, which is what confuses me, but I did recently find an old for sale sign under a the passenger seat and it said "has motor problem". Anyways, after listening to videos of different engine noises the closest I could find was of bad main bearings. I will try to get under it this week for a real good going over seeing as though we're actually getting a week of good weather. I keep thinking it has to be the exhaust, but I grabbed the cat section and tried yanking and pushing pretty hard and it didn't budge. When I looked before it was pretty cold so idk, maybe it clouded my judgement. I'd be fine with finding out it was something easy and make me look dumb right now, lol, but with my luck lately, idk.

The URL to the video of it running: http://www.youtube.com/watch?v=6DGP-a-mCEA

Atilla the Fun

I guess at this point the next step is to pull the oil pan, and start checking the bottom end. If it is a main bearing, you're replacing the entire short block. If it's a rod bearing, then you could save the block, but if it's a 305, why bother. Maybe you'll find it's something less serious than a bad bearing.

5-0 Blackbird

Ya, I've been wanting to take the pan off and check it out, but the weather has been against me until this week. I won't know much till then. The motor is a casting 3970010, seems to be a pretty popular 70-80 Chevy 350 block. Anyways, thanks for the help, I guess I'll have to check it out and if need be, I'll choose whatever engine presents itself as a good choice first, whether it be a Vortec 350 or another older 350. Thanks again Atilla