New poster here. I have just acquired a 55 Chevy with a LS376/480 crate engine. I have no documentation to verify that, is there any way to externally tell if it is a 430 vs 480? (yes i have searched this forum a bunch but no luck) Builder is no longer in existence. I understand that the only difference is the cam and i checked GM's crate engine site and both have the same block part numbers (12623967) Interesting in that the only stamped number i could see at the rear drivers side of the block is 0310663? It looks like my setup has the standard GM Erod harness and controller. I reckon i could disconnect the controller and check the PN on the rear of it as the 430 supposedly has a different controller than the 480 as far as part numbers...I'm assuming those numbers would be on the rear tag of the ECM? Just trying to verify what i have as i am having a driveability issue with the dreaded surge from 1700-2500 rpm (manual Tremec tranny). I know from this forum that is common with some modded LS engines but i am told by others that a stock Crate engine with GM controller should have no such issue and that tuning is not the answer. Also I'm pretty sure there is not a stock ECM tune as this was running poorly before i acquired it, the car was sent to a tuner (Mass Acceleration Motorsports) and they had to "Unlock" the ECM and then they dyno retuned it. They indicated that a stock ECM would not be locked so they figured it had an aftermarket tune?
That was immediately before i acquired it...unfortunately what they did was ineffectual as it ran on only 4 cylinders when i got it. 2 main problems a stuck 02 sensor was resulting in a fuel trim of 50 on one bank thus totally flooding that bank out. Then it was discovered no fire to coils on the same entire bank...faulty wiring to a critical connect pin that provided power to the coils.
Anyway it's looking like i may have to try another tuner to iron out the surge.
But to my original question....I'm assuming there is no way (externally) to tell if 430 vs 480, one reason is i want to verify that i have the correct ECM installed since they are different or at least have different programing. Anyway this has been the crappiest running car i have ever had and i have had some real POS cars and some highly modded ones as well.

 

You are correct. The ONLY difference between the 430 and 480 IS the cam. Nothing else, except the tune.
The main thing to do now is get the wiring straightened out. Make sure ALL grounds are connected. They are very important.
Then check continuity on all connections.
You have a good combo. Once lined out it will RUN!

 

I have a stock crate LS3/430 in mine running on a stock E38 08 Corvette ecu. Idles like an Accord at 675 rpm....no surge anywhere on the tach. Drives/runs/fuel mileage like an oem application. As a “stock” data point. 480 is cam and tune.

 

As already stated, the only difference between the '430' and the '480' crate engines is the cam.

There is no way to tell externally through inspection to determine what engine you have; you'd have to pull and inspect the cam in the engine.

The Hot cam in the '480' is a nice, mild performance cam.....but if that's what you have, you can easily do better from a performance standpoint.

Almost any other performance cam you could go with will require a valve-spring upgrade.

KW

 

Thanks guys, I'm just trying to get this "nice mild performance cam"ed LS3 to run marginally well.
Right now I'm chasing down this electrical issue that has killed 2 batteries in 3 months, there happens to be a .6 amp (not milli amp) parasitic draw....that means about 3 days of battery life if i forget to hit the disconnect. It does have the Infinitybox wiring system with the "InReserve" option that is supposed to monitor battery voltage and shut it down if below 12.2 volts are sensed for over 15 minutes. That function has failed twice so i need to manually kill it all...i reckon perhaps the InReserve function is not wired correctly.

 

.6 amp should be easy to trace. I hope you find it!

 

Perhaps the InReserve malfunction IS the source of the .6A draw....

 

^^^^^^^^This!^^^^^^^