October 2010 Chevy High Performance Q&A

Kevin McClelland Aug 30, 2010 0 Comment(s)
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I called around with my setup info. Scoggin-Dickey recommends their Z-cam, and Patriot Performance and Comp Cams have custom grinds, but I'm surprised by the amount of lift. All of the LSAs are between 110 and 114. With some suspension tweaking and slicks I'm looking to get the car in the 7s in the eighth-mile. What kind of estimated power am I looking at the flywheel, and to the ground?
Zack Rich
Via email

A: This swap is going to become the norm. With prices dropping on the LS engines, and their lightweight power potential, it's just a natural progression of hot rodding. Put the biggest, most powerful engine in whatever we have. We like it!

The GM Performance Parts Hot camshaft was the first aftermarket cam available for the LS1 engine. We were lucky enough to be a part of that development. As you know, GMPP has the Hot cam for the Gen I and II engines that is very popular. Basically, not knowing what the LS1 engine architecture wanted, we just copied the small-block Hot camshaft on an LS1 master. Yes, as a first whack it ran quite well in the fuel injected LS1. Now we're 15 years into the LS engine family's run and there have been major advancements in cylinder heads and camshaft designs. At the time, we copied the 0.525-inch max lift to work with the net lash valvetrain on the LS1s. This allowed us to retain the factory base circle dimension.

Don't be concerned with the lift that is being ground into these performance profiles for the LS engines. The cylinder head flow capability is right in these ranges. The factory LS2 engines are in the 0.550-inch lift range. Many valvesprings on the market will live at the low 0.600-inch range on the street. With your gears, converter, and performance goal, we'd step the camshaft up from the very streetable Scoggin-Dickey 220/224 Z-cam. Look at the new LSR Cathedral Port cam (grind number 281LR HR13, PN 54-459-11) from Comp Cams, with a hot 231/239 duration at 0.050-inch tappet lift, 0.617/0.624-inch max lift, ground on 113 centers, that will wake up the LQ4 you're running.

You will need to upgrade to Comp valvesprings (PN 26926-16) with retainers (PN 1779-16). These dual valvesprings have an outer diameter of 1.320-inches and have an installed pressure of 129 pounds on the seat. These springs were specifically designed for the LSR camshaft profiles Comp just released.

This camshaft, with your current engine, intake, and exhaust package should give you around 450 hp. With the truck heads, you will need to replace the very heavy intake valves to raise the limiting speed of the engine. You could swap out to the LS2 intake valves, which will reduce the mass by about 30 grams. There are very affordable LS2/LS6 takeoffs out in the marketplace that will give you the lightweight valves and will add about 0.7 CR to your 9.5:1 LQ4. With this large camshaft, the added compression would be a welcome addition and the light intake valve will stabilize the valvetrain. As for power at the ground, we would take away 18-20 percent from the crankshaft numbers for the driveline, accessories, and stall converter losses.

Get your Monte together and get back to us on your performance numbers. This should get you to your target for eighth-mile e.t.'s. Also, put that thing on as much of a diet as you can. Any weight you get out will give you gains in performance and consistency. Have fun with your project.
Sources: compcams.com, sdps2000.com

Bent Monty
Q:I've been a subscriber for 10 years or so and love the rag. My question is about my '83 Monte Carlo with a bent lower control arm. I bought it without knowing it (an arm mounting bracket) was bent beyond repair. I have two possible donor cars for a frame swap: a '79 four-door Malibu and an '84 Cutlass four-door. Will either one work, or if not, what would be a good car for the swap? It now has a 350 and a TH350 with a stock 7.5-inch rearend. I love the G-bodies and have upgrades in mind, but I'm at a standstill.
Wes Snyder
Clayton, WA


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