brasher801

Can I get 350+ horse power out of the 350 that came in my 1980 c3? What changes must be made to do this? and will it still be a dependable streetable car? It's mear 190 horse right now seems to me to be a disgrace to any vett. Looking for more power.

71rdster

Put a crate motor in it. It will be cheaper than trying to get that kind of hp out of your stock motor.

JLeatherman

Really? A 350 is a 350. If your has good compression, not too many miles on it, etc I'd think this is quite possible. Heads, cam, intake, and a good exhaust. Still be cheaper than a crate motor. If yours has 100,000 miles on it and smokes a bit, or your test compression and one or two cylinders are down in the 120's, then it's probably crate motor time. Although, my last 355 shortblock was under $1,000 (built it myself). Add heads, cam, intake to that and I probably could have easily had 350hp outta that one for under $2,500. If you can do it yourself it's always cheaper. And a 350 chevy is as simple as it gets man.

DEMITRISTYLES

Get the GM 350HO crate 330HP/380Torque.

WillEE

You could spend $4k on a crate motor plus carb, intake distributor and misc. items totaling another $900 or to get 350hp for about $5k or work with what you got and be looking at following

Pistons, rings, & machinework = $800
New alum. heads = $1,200
cam kit = $150 - $500 depending on if roller or not
carb = $300
Intake = $200
Dist = $250
Misc. stuff $200 (head bolts, bearings, gaskets, etc.)
re-use block, crank conn. rods, oil pan,
Do majority of work yourself

Total: $3,000 approx.

That saves about $2k and you get the satisfaction of knowing you did it. With this route you'll need to do your homework and read so you can say you did it right!

I've done both routes but nothing really beats the satisfaction of accomplishing an engine build on your own. Gives you character and confidence to do lot of other things that you may not normally attempt.

WillEE

To answer your other question - yes a SB Chevy can be built to 350hp and still be as reliable or more so than your stock eng.

JLeatherman

Frankly, I'm still not sold on aluminum heads if all you're looking for is 350 hp. These days there are several good choices for out-of-the-box iron heads that will flow plenty for 350 horses. On the street I'm still a fan of iron heads because they're forgiving of little mistakes (like heat). If you're block doesn't need machining (compression test it) you can do this with it in the car and for ~$1,000 less than the $3k that WillEE quoted. Although, his is the right way and it is damned satisfying to fire up an engine you built with your bare hands for the first time. Nothin' beats it.

71rdster

This is true, but I have one word for you - Waranty. Crate motors gotem, the one you build don't. Not to mention the fact that good quality machine shop work is a rarity these days. And I would guess that some of the parts cost estimates WillEE put out were a tad low. The crate motor suggestion is a shortcut to your 350 hp performance, and you can always stick your original motor over in the corner for future buyers of your car. Plus, you can have your Crate motor tomorrow in many cases.

chevr0letman

Quality machinists are a dime-a-dozen these days, I don't see where you get they're a rarity. In the valley alone there are about 20 top notch machine shops. Its actually hard to find a machine shop that doesn't know what they are doing. Sure you can have your crate motor tomorrow, but in many cases you can buy all your parts at once and have your motor rebuilt in a week if you know what you are doing.

And as for a warranty... if you need one, you have no business in a corvette with a hopped up 350.

billla

With a decent top - heads, cam, intake, carb, headers it's definitely possible to get close to 1HP/CID at the flywheel. Good comments in the thread on all the factors; is originality important? Is the shortblock in decent shape?

If you've got a good shortblock a Vortec or similar type top will get you in the ballpark with the right cam and headers.

I would suggest maximizing what you've got first - "more power" can be had in headers and exhaust, torque converter and a good tune...sometimes as much power as you'd like to have, and at a very reasonable price

billla

I'll respectfully disagree - I see a ton of shops doing lousy work, unfortunately.

Key phrase - if you know what you're doing. I agree that doing a performance overhaul isn't rocket science, but if you've never done it IMHO you need a good mentor to get you through it.

WillEE

The key to a good machine shop is to ask people who know what they are talking about and have some experience. Typically the machine shop that does a lot of circle track engines in your town will be the good one. Those that don't do many race engines will be the ones to watch out for. You want a shop that is more known for working with local racers. They will do things the right way cause their repuation will get around the tracks quickly if not.

Like I said above, I've done both ways and they have pros & cons. but will say the the ZZ383 I put in my '68 camaro had an issue at start up that wouldn't have happened if I assembled the engine myself. Some idiot at the fGMPP actory did not torque down the rocker studs on one head and they started loosening right away. Fortunately I could hear one clacking and shut it down. As for the warranty - they wanted me to pay to tow my car 30 miles to a dealership to have someone who knows nothing about perfromance engines work on it. I told them to send me a new pushrod and rocker arm (one got nicked when it went sideways after loosening) or I would send the hole engine back. They agreed and I went through and removed all the rocker studs and installed loc-tite (keeps them in and prevents oil seepage through threads) and re-torqued them. Something they didn't do at the factory. Don't be fooled - if you do your homework you will do a better job than GMPP does assembling your engine and you'll know it's all done right. Question for yourself - is $2k extra worth a warranty that may not be very helpful anyway? If your into the hobby and adventure and aren't scared to get your hands dirty then think about the excitement of doing this yourself. Pulling it in and out is 1/2 the work and you have to do that with the crate engine anyway. If you can turn a wrench, read and follow directions you can build yourself a real nice 350hp SB engine for fairly inexpensive $.

billla

Well, like Larry the Cable Guy says..."I can do this all day"

In my experience racing shops tend to be the worst shops, but everyone's experience differs. They can definitely hold a tolerance, but they tend to overbuild and overspend. In the end the home builder needs a Level III+ shop that is willing to work WITH them to build and engine - it's kinda like being a general contractor.

No question that the General puts together the occasional lemon - I've seen a couple of GMPP 350/260 and /290 engines that were embarassing. BUT, looked at on a percentage basis their track record is pretty darn good...and IMHO way better than a home builder that's never done it before and has no precision tools.

Again, don't get me wrong - I firmly believe in doing overhauls vs. buying crates, and I agree that you can get more engine/$ at power levels of 1HP/CID or higher. But IMHO a new builder MUST have a mentor to be successful.

WillEE

It would obviously be ideal to have a mentor but DEFINITELY NOT A MUST if you're type of person who is ambitious, hungry to figure things out and plan each step. I rebuilt my dirt bike engine by myself when I was 11 with my Dad's tools and talking to the guy at the store where I bought the parts. So a "grown-up" can sure read magazines, explore the massive amount of internet resources available today, etc. and accomplish this relatively easily and very successfully. My first SB350 was done on my apt. kitchen floor and with the block machined, I put it all together in one night and was breaking it in by sunset the next day. Of course I had paid my dues by reading a lot about the process first since I did not have a mentor available. This was before crate engines became the fad. The engine was 375hp and served me very well for a decade w/o a single leak or problem. It was running fine but I wanted more power so rebuilt it again.

As for racing shops being "worst shops" - that's just generally rediculous! Yes they'll typically charge a little more since their techs. are among the best and better paid and have nicer equipment but you'll have a much better end-product and the extra $100 or so will be well spent. They are also more willing to talk to you about your goals for the engine. I suppose different experiences create very differring impressions here.

I'm not wanting to argue for sake of argueing but I think someone deserves a fair shot here to try and pursue an engine build themselves if they have the desire. I've seen many novices do it well. The ones I've seen fail are because they don't have patience and aren't willing to do some research. You have to be able to step back and look at the big picture and then disect each process. This really isn't difficult when applied to an engine build if individual has some mechanical aptitude. That's been my experience. Someday I'd love to be a mentor in this and other regards and think they are valuable but not a must.

Kadorja

I'm planning a big engine swap when I get back from my deployment. 350 w/ 400hp and 400 ft-lb of torque. Its only $3k but I have to get the carb, water pump, ect ect. I plan on doing that, bowtie overdrive trans, VBP hi performance suspension, and possibly a procharger but that would be pushing it. 650hp with a stock rear end wont end well I'm sure. I would like to do it all myself but I just don't have the time to work on it. Its my daily driver so I want something reliable and definately streetable.

P.S. To make myself feel better in my car I usually just try to keep my sidepipes nice and shiny so go get some!

billla

I just see too many engines that come into my shop that have the rods on backwards, cam timing off, etc. Can someone do it? Yes, absolutely. Are the risks higher? Yes, absolutely. Cost of a mistake? Maybe an engine. For a guy that gets maybe one shot to build one of these, I just don't think it's a home build process without an experienced friend helping out.

Again, very different experiences. I've seen two race shops here in Seattle sell splayed 4-bolt caps, forged cranks, etc. for a 350HP build...so as for "rediculous", that hasn't been my experience.

I don't think anyone's keeping anyone from a "fair shot" to do their own build. And if it was just an overhaul, I'd give a very different answer. But when it moves from an overhaul to a performance build with all the detail work required - valvetrain geometry, quench, etc. I've just seen too many people get into trouble.

In the end, the builder has to make their own choice. After 150+ SBC builds, I'm just offering one perspective.

bozzman3

By a top end kit like I did and start ripping off 13 sec runs at the track!!Trick flow and Eldebrock make some real nice kits

spedaleden

HP is not cheap!

I just dynoed mine

GM 385 Fast Burn with Hot Cam and 1.6 RR
Headers Cats and Magnaflows
Tremec 5 Speed with 3.55 rear end gear

290 RWHP

GM says my motor is 400HP at flywheel with no accessories on the motor when they ran there motor for specs, so any grate motor you buy deduct 30 to 40 HP for accessories, (Air water, alt, power steering, fan) and add 15% loss through the drive line and if you look at the numbers it does make sense. The 5 speed is getting me 19MPG as long as you shift like a weasel.

Good Luck

timgman

Geesh... if the thing isn't worn out to oblivion, has good oil pressure, compression test looks good and it is a nice runner just get a top end kit / cam... and spend the spare change on a better exhaust systems... RWHP is more important than crate engine number magic....

timgman

BTW, a racing engine machine shop did my 383... and my 383 is mild my many standards.
(high end internals but street cam (350 350).....and re-sprung vortecs.
I'm not saying that all racing machine shops are pro's but this one was....