496 Cubic Inches
8.1 General Info
- Exhaust - Cutting off the cats is not going to do a thing for power . If anything you may loose some low end. Typical cat back exhaust or mufflers only will be fine. Shorty headers will not provide any power gains either as they are qutie large from the factory and are in a tubular design already. Long tubes will however provide some gains but how much is not really known. Check here for flow tests between major brand mufflers.
- Aftermarket Hard Parts - Look into Raylar Engines or Arizona Speed. Bring a fat wallet.
- TB spacers - No gains from users. Waste of money and time.
- Bigger TB - See here
- 8.1L motor part numbers and such - PDF
- Crank Positioning Sensor - May or may not throw a code. Common symptoms include stalling, lack of power, and hard starting to name a few. There is a new design on the new ones that offer less problems. Can be done yourself.
- Loss of oil - Common and nothing to worry about if less than 2 qts between changes. Using a thicker oil such as 10W-30 will help this especially if your running a full synthetic as it tends to be a bit on the lighter side anyways.
- Low oil pressure - Also common. Norm is ~26-30 idle and 40+ cruising. Again thicker oil will dramatically increase this and not all have this problem.
Tips and Tricks
- Plug Mod - Use AC Delco 41-932 (newer # now) and gap them at .045. This helps combustion and throttle response among other obvious things. This mod I am currently testing for thoroughness. Check back later.
- Thermostat - Use a 180* thermostat to help with detonation and under hood temps. Can be purchased at Auto Zone. PN 15898 Duralast. Can use with no other mods. Double check PN's when at parts store. In addition you can also use a 160* thermostat without any computer DICs either. I run one in summer months for two years now without any problems. Stays a constant 182* even towing in 90* weather and A/C on. PN is Hypertech 1005 (IIRC). It is same thermostat that was in previous generation of Silverados with the Vortech 454ci motor.
- Cold Air Intake - Check this out for complete rundown.
- Tuning - While there are a few hand held tuners out there they provide only marginal gains. Plain and simple if you want the most out of your motor go EFI Live or equivalent. There are many mail order tunes that offer roughly the same gains and are significantly cheaper. If you dont plan on using all of EFI Live's features and want a mail order tune some examples in no order are: Westers, Nelson, Wait4Me,and Blackbear. Use at your own risk. If you MUST have a hand held Diablo Sport's Predator is the most complete and allows some torque management removal.
- Nitrous - It can be done with proper tuning and a reasonable conservative shot. Would not recommend for a novice.