DigitalWidgets

So, my 2011 Grand Sport with 160K miles on it seems to have something major wrong with the engine....the last moments it actually ran it sounded like someone was under the hood beating it with a hammer. I've had several friends who where there and heard it (it happened at an autocross event with several "car guys" standing right there). Basically all the theories boiled down to major trouble, look to rebuild the engine, etc. The car has 160K miles on it and has been autocrossed and tracked for all of its life (and for all intents and purposes been pretty bullet proof all these years). I figured with this many miles on it, why waste money on fixing a tired engine, I can buy a new GM Performance crate motor for well under 10K, and when I think about there's no other car out there that I could buy to replace this car for under 15K, so why not just put a new motor in and continue to beat on it for another 100K miles.

I've been looking at the GM Performance crate motor options. They have exact same 430HP LS3 available (like $7900ish)...but GM Performance also has a LS376/525 motor with like 95 more horsepower for like $9600ish....so my thinking is, why not get 95 more horsepower for only $1800. From my research, they sound like the same exact engine, but the higher horsepower comes from an "aggressive ASA camshaft" and a few other upgraded goodies to support that (rockers, valves, I don't exactly know what).

So...my question: Is that a sound line of thinking? It appears to all be the exact same otherwise. That being said, I have had some friends say that doing the LS376/525 motor will cause me some issues with passing smog (I live in California)....I don't know specifically, but I'm hoping that an OEM engine wouldn't create a bunch of issues here.

My final thinking: The car is in great shape otherwise (everybody is quite surprised when I share it has 160K+ miles on it). It's relegated to just being my "beater" for tooling around cones in a parking lot (several times per month) or occasional trips to the local track for a few sessions. It's been dead sitting on a lift for over a month now (the motors seem to all be on backorder at the moment). I've got two potential folks to work on the car, one's a LS3 rebuilder expert...but I'd need to get the motor pulled and just take it to him and then get it put back in (big hassle factor) and the other isn't really a Corvette shop (but they've done LS swaps before).

And to throw one last thing into the mix, I've got a friend with a Honda S2000 that he's looking to get rid of that I could also potentially pick up and beat on for a bit.

I'd love to hear some input from y'all.

BacknBlack08

The 525hp motor sound like the way to go, though I'm always for more power lol. I think a couple of other things to keep in mind is unless you have an HP tuner or similar programmer I don't think the parameters for your stock LS3 would work and the ECU would need to be programmed for the increase power. Transmission may be an issue as well, if it's automatic you might need increase converter stall with the larger camshaft. If your manual I'd think your good to go with a clutch replacement esp. @ 160k lol. Just some thoughts!
BNB08

DigitalWidgets

Ah....I didn't think about a tuner mapping it out. It is an A6 (although I pretty much paddle shift it exclusively until I'm on a freeway). In it's current life as an autocross car it does spend most of it time pedal to the floor in 2nd gear. I didn't really consider the transmission, will need to factor that in for sure.

old motorhead

The inspection station will hear your car coming from a block away. Nothing stealth about the ASA cam. It will lope and have a VERY choppy idle. At 11 degrees of overlap, there's no hiding it. Buy the 430 hp LS3 and add a lot milder cam than that. One that might at least have a chance of running smoothly with the stock tune. I don't think there's much difference between the 430 and 525 HP LS3 other than cam and exhaust. Just a cam swap in a stock LS3 powered Vette won't show a 95 HP increase. You can't use long tube headers anyway and I'm guessing GM used long tubes to get the HP up that high. Probably says it's for off road use only too.