November 2010 Chevy High Performance Q&A - Performance Q&A

Kevin McClelland Oct 12, 2010 0 Comment(s)
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Right now, I have a borrowed 305ci, Summit cam and lifters, and a set of 305 heads with larger valves installed. I am in the hunt for more power and since I don't own the motor, I'm not going to tear it apart and rebuild it. I have been looking around for information on swapping a LS-series motor in. With the factory roller valvetrain and stout bottom end, these are great power engines for the money. I want to steer away from EFI-too much headache for tuning. Could you guys help me out with a very tight-budgeted swap of a LS motor into my Monte? Also, could I get away with swapping out cams and not the roller lifters? My budget isn't much to work with, but I've got to go faster.
Alex Tipton
Chester, NE

A: I know we all have a need for speed, but focus on your education right now. Yes, you can work toward swapping in a new engine, and this is a perfect way. Get all your ducks in a row and then pull the trigger. Swapping in an LS-based engine will be the best upgrade you'll ever do to your Monte. Doing it on the cheap may be a little difficult. If you're willing to make some of your swap components, it can save you a ton of money. However, you need the space and facilities to do this. I'll try to be gentle choosing the parts to make your speed fix real.

First, you need to find an affordable engine. LS1s are very plentiful for very reasonable prices. We would look for either an LQ4 or an LQ9 6.0L truck engine. These had a cast-iron block with aluminum heads. The blocks are about 50 pounds heavier than the aluminum LS blocks, but the engines are cheaper and have more displacement. Also, it gives you a 4.00-inch bore for upgrades in the future. You can swap out for a higher performance hydraulic-roller camshaft without replacing the factory roller tappets. You'll need to install the appropriate valvesprings to match the lift curve of your new stick.

Next, you need to get the engine in your car. For a very nice swap package, check out BRP Hot Rods for very well-engineered engine mounts, trans crossmembers, and header packages to drop your new LS engine right into your Monte. BRP also offers what it calls the LH8 oil pan package, which consists of an OEM pan, oil pump pickup, and correct windage tray. Again, this works with the swap package for a no-drama install.

Edelbrock offers dual-plane Performer, Victor Jr, and Super Victor intake manifolds for the LS engines based on your cylinder heads of choice, satisfying your needs from idle to 8,000 rpm. Milodon has a complete line of LS swap oil pans, from the street swap pan to its racing pan for early to late Chevy iron. These pans are shallower than stock at a 6-inch sump; however, they have a 7-quart capacity.

To give you the spark you need, check with MSD for its stand-alone 6LS ignition system and harness. This makes the spark side of your swap a snap. The controller allows you to map a timing advance curve with MSD's easy-to-use Pro-Data+ software. Other programmable features include a two-step rev limiter, a vacuum advance curve for cruising economy, and even a step retard in case you want to add a little nitrous to the mix. MSD offers two systems that will support either the 24X or 58X crankshaft reluctor wheels.

Last but not least, to use an LS engine with an early (non-LS) transmission, you'll need to run a flexplate spacer. The crankshaft face is 0.400-inch farther forward in relationship to the bellhousing surface of the block. GM Performance Parts makes a spacer sold under PN 12563532, and you need six new flexplate bolts (PN 12563533). This will space the flexplate back to the proper dimension to engage properly with your torque converter. Good luck with your Monte upgrade.
Sources: brphotrods.com, edelbrock.com, gmperformanceparts.com, milodon.com, msdignition.com

Technical questions for Kevin McClelland can be sent to him at chevyhi@sorc.com.

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