VM: Is the LSX 454 a better choice for a classic Vette--a 67, for example--or a late-model LS-equipped Vette?
JM: This is a difficult question because a custom Vette is such a personal choice. We feel that there will be a number of LSX 454 crate engines that find their way into both markets--classic retro-mod Vettes as well as replace-ment engines for a tired LS1. Either way, the LSX 454 will offer an amazing level of performance for the price.
VM: For Corvette owners who want to add power adders to the LSX 454, what are your suggestions?
JM: Right up front, I have to state that GM Performance Parts has not tested or validated the LSX 454 with any power adder. Because of this, if you modify the engine--including running a power adder on it--you will void your warranty. Youre on your own. I dont think thats too hard for folks to understand.
Okay, now that we all understand that, I will say that this engine certainly has the potential to be a real monster if you add a power adder. A small nitrous system--like 300 horses--would bolt right on. With forced induction, you could go quite a ways before you [had to] go into the engine, given the right fuel octane and careful tuning. If you use a lower-compression piston--something like 9.0:1--youll have a 454-inch LS engine that will take a lot of boost. What is "a lot"? Im not sure how far you can push an LSX 454, but Im sure someone will show me.
In theory, it would be quite simple to have a 1,000 horse-engine that starts, idles, and runs with good manners. Its an amazing time to be into hot rods.
VM: Im sure youve done comparisons between the LSX 454 in carbureted and fuel-injected form. When does a carburetor make more sense, and when is EFI better? How large a carburetor can the LSX 454 handle? How about dual or triple carbs?
JM: The advantages of the carb are that its easier to install and makes better power, all things being equal. We are testing 850-cfm carbs on the LSX 454, so Id start there.
The LS7 fuel-injected intake is a great choice if you like the manners and big torque of an injected engine. It also offers unsurpassed fuel efficiency once tuned properly. This [intake uses] a 90mm throttle body set up with 40-lb/hr injectors.
As for dual- or tri-carb setups, Im sure someone will do it. It sounds like fun. Or, how about using the GMPP LSX carbureted intake, putting an elbow and throttle body on it, and putting fuel injectors in the provided bungs? Personally, that would be my preferred setup.
VM: Does the LSX 454 allow a variety of transmissions? Which ones are recommended by GMPP?
JM: For transmission selection, a Tremec 6060 would be able to hold the power and torque given the correct clutch setup. For an automatic application, any of our RPO transmissions will fit; however, our new Supermatic 4L85-E, which has been tested and validated behind the ZZ572/620, is the way to go.
VM: Say youve got two Corvettes--one with an LSX 454, and the other with an LS9--at the starting line of the quarter-mile. Everything else being equal, which one wins?
JM: Oh, man, how do I answer this one? Its an interesting comparison, and both engines have their advantages. Did I mention that the LS9 has just been released as a crate engine from GM Performance Parts? Back to your question, I think theyll both cross the finish line in under 10 seconds--assuming slicks and all the supporting equipment--and both drivers will have really big grins on their faces.