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Hello,

I'm looking at buying a remanufactured '72 Corvette engine for my '55 from Advance Auto Parts. The 350 hp version is about $200 more than the 300 hp version but it's a 9:1 compression ratio engine so I assume that I'll have to run premium in it. The car is a driver and the existing stock 350 has plenty of power.

It's not like it's going to be a huge difference in price between engines or fuel costs since it's a hobby ride, but would you rather drop the 300 hp or 350 hp into your tri-five?

Bill J., Lexington, KY
 

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IF you ever wish you had more HP

then go for the 350 hp
but if your concerned about MPG, and fuel costs, then go with the 300hp.
you should be able to use reg with 9 to 1 , depending on timing.

my preference would be the 350hp, as I would like the additional power available,
either way, you should be happy with a fresh motor to keep you cruising!
 

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Exactly how much money are we talking about? Hard to say what kind of quality you're getting from a parts store engine. It could be their mass-rebuilder knurled the valve guides, reconditioned the rods, and used the cheapest pistons, rings, and bearings available. Sometimes they will overbore the block .060" and grind the crank .030". Not the best way to do things.

Also what transmission and axle ratio does your car have, and how do you intend to drive it? Depending on what components were used to get the extra 50 horsepower, you may be giving up some torque. Sometimes companies will do this by using a bigger cam with no change of heads or compression ratio. The results are a loss of torque and driveability in exchange for more horsepower at 5000 RPM.

Have you considered having yours rebuilt properly by a local machine shop?
 

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Advance Auto? Corvette 350? Really?
I had a friend with an engine exchange business. He got a lot of work replacing parts store engines that failed.
I don't know anything about Advance Auto, but I'd look around a little.
9 to 1 would still be 87 octane. I've got a crate 290 HP engine and all I've run is 87 octane in it. It's fine for the cruizin' I do. My racing days are long gone.
 

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Advance Auto? Corvette 350? Really?
I had a friend with an engine exchange business. He got a lot of work replacing parts store engines that failed.
Maybe I should have said those mass market rebuilders sometimes bore the blocks .063", which I've actually seen. Well OK, it was only on a few of the cylinders. The others were .060-.062". Seriously.

Also, they aren't shy about taking a lot of material off the block decks, sometimes so much that they must use "rebuilder" pistons that are shorter than stock.
 

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Discussion Starter · #9 ·
Advance Auto? Corvette 350? Really?
I had a friend with an engine exchange business. He got a lot of work replacing parts store engines that failed.
I don't know anything about Advance Auto, but I'd look around a little.
9 to 1 would still be 87 octane. I've got a crate 290 HP engine and all I've run is 87 octane in it. It's fine for the cruizin' I do. My racing days are long gone.
Thanks for the good advice. I'm going to listen to you fine folks and look into getting a 290 hp 350 gm crate engine.
 

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The L-31 350 Vortec truck motor is the best crate motor deal for a relatively stock SBC right now. You get Vortec heads and a factory roller valvetrain. SAE net HP rating was 255 HP with a tiny, tiny roller cam (191/196 at .050) with stock cast iron exhaust manifolds and truck exhaust. It's an easy 300 gross HP motor which makes it comparable to (actually probably more powerful than) the GM 290 HP motor. It's also about the same price too.

What really makes this motor shine is the heads and the roller cam. That's a $1000+ investment in a pre'86 block that you're basically getting for nothing.

Throw on a set of headers, a decent intake manifold and carb along with a bigger cam and upgrade the valvesprings and you have 375 HP motor easily. You'll end up doing the headers, intake, and carb with any 350 anyway so that's a wash. A cam and valvespring upgrade is $500 max.

Only downside to the L-31 is that you will need to use an electric fuel pump, but that's really no biggie.

http://www.jegs.com/p/Chevrolet-Per...ci-L31-R-Long-Block-Assembly/1532025/10002/-1
 

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Adding to what Chad said, any engine with Vortec heads will make more horsepower without using a big cam. Not only do the heads flow better, their high-swirl design supports higher compression without detonation. And another nice thing about the engine he recommend is the roller cam. No worries about using oil with lots of ZDDP, and there are plenty of cam upgrade options for the future without having to change lifters. Also the engine will make more street-friendly torque than either the 260hp or 290hp engines that use low compression, old-tech, large chamber heads.

Yes, that 255hp number is "net" horsepower as installed in a late 90s pickup with all accessories connected, whereas the 260 and 290 numbers for the other engines are "gross" hp at the flywheel. If the roller cam engine had a gross horsepower rating, it would probably be 300 or more. Having driven one of those 1/2 ton pickups when the Vortec engines were introduced, I can tell you they were a HUGE leap in power vs. previous 5.7L engines with standard heads, which were rated at somewhere around 200 or 210 net horsepower.

Finally, Jeg's has a special deal where GM crate engines ship free. Check them out. http://www.jegs.com/s/GM_Engines/GMEngines_freeshipping.html
 

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50 HP for $200= $4/HP. That's the cheapest HP you will ever buy!!!
HP takes additional compression, cam and fuel, so likely the 350 HP will idle a bit rougher and use a little more fuel. Not a problem for me!!
Are their rebuilds dyno'd or are they just speculating on HP?
I agree with the others in checking price against GM Performance. When I looked around, GMP pricing was tough to beat.
 

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Call me different but I have no use for crate moter, its like buying a pre fabbed house. However, I guess everyone does not have a garage full of cores and good friends that own machine shops. Half the fun of it for me is assembling the thing yourself.
 

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Mark, I've built many engines over the years, including my 55's 327, but I'd seriously consider the GMPP 330hp 350 for my next project. And I recommend the base Goodwrench engine to guys on a budget who care more about low-mid range torque than horsepower at higher revs. Don't forget, not everyone with a Tri-five can or wants to assemble their own engine.
 

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I guess I am old 15 inch wheels, I like old moters like 283, 327 or 396.
I'm looking for a somewhat unmolested 283 or 327 to build back up to near factory specs. Not for any specific project, but "just because". Ideally it would be a 300hp/327, but I'd take a 250hp/327 or 220hp/283.
 

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The l31 vortec long block makes 315 hp with a edelbrock air gap dual plane, a holley 4bbl tbi and headers, pace performance sells that as a turnkey package that they dyno tested.
Changing the tbi out for a properly tuned carb will make the same hp.
the gmpp 330 hp vortec motor has a flat tappet cam, and chromed valve covers and timing chain covers and can use a mechanical fuel pump

Cost wise the base gmpp 330 hp 350 is about $ 3000 vs $ 2000 for the 4bolt main l31-long block, either block will cost you about the same to complete., the 1000 you save and after the warranty runs out can go into a gm lt4 hot cam and the springs, retainers and seals and you will have a 375hp
350. and you will still have savings that can be applied elsewhere.

Regards, Robert
 

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I'm looking for a somewhat unmolested 283 or 327 to build back up to near factory specs. Not for any specific project, but "just because". Ideally it would be a 300hp/327, but I'd take a 250hp/327 or 220hp/283.
I have started a 57 model 283 like that I just had 1.84 intake valves from a HO 305 installed in some 539 castings along with seats guides etc.
 

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The 1000 you save and after the warranty runs out can go into a gm lt4 hot cam and the springs, retainers and seals and you will have a 375hp 350.

Regards, Robert
Hmmm. Good idea. But I'm thinking you'd need better heads and more compression to get that hot cam to work. And with anything more than around .470" lift, those heads will need to have the valve guide bosses machined.
 

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personally i like throwing revs every once and a while...so a bigger hp motor usually sounds tougher than a stock hp motor. might as well put some 40 series flowmasters as well. idk. perhaps i'm not as young as i once was...cuz i'm starting to like new looking, nice stuff. vs motors that i have run the dog snot out of, that look run hard and put away wet. lol. that being said...i beat the dog when i jump on the freeway a lot.
 
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