October 2010 Chevy High Performance Q&A

Kevin McClelland Aug 30, 2010 0 Comment(s)
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Purpose-Built
We all get that wild hair up at times to build something very cool. I'm sure if you sat back and thought of what you'd really love to build (and didn't have a budget) you could come up with quite a dream machine. Many times, as much thought as we give to what we want our car or truck to be, we really don't consider what it would take to make that dream a really useful street or race car. I've always wanted a Gen II Corvette ('63-67) because my good friend Kenny Morelli had a '63 when we were growing up. My dream Vette would be an ultralight street/track car with a twin-turbo'd aluminum big-inch small-block, six speed ... You notice the lack of details-I just want it! This thing would be scary fast and handle like it was on rails.

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Now let's come back to reality for a minute. Last weekend, Daniel and I were racing at Fontana and we lost a full day of racing on Saturday because of high winds. The promoter decided to run two complete races on Sunday. Well, without my Roadster running, Daniel and I have been sharing the Wagon. I asked the promoter if we could double dip with the wagon. Daniel ran in the Stock/Superstock combo class, and I ran the No Electronics class. Between the two of us, we raced four complete races in one day, for a total of 16 runs! Daniel lost in the finals of one race and in the semis of the other, and I went two rounds in my first and three rounds in my second. We were driving this thing in circles, coming straight back to the lanes after every run.

The "purpose-built" theme? When I came up with the idea to build this car for Stock Eliminator, I knew most of its time would be spent bracket racing with our mild 350 small-block. In the planning stages, I knew that the car would be hot lapped (deep into rounds of eliminations where you get minimal cool-down time). During the design phase there were things I knew we would need, namely a cooling system to control the temps within a repeatable range that would allow for consistent performance output, including a transmission cooling system that would keep the gearbox and converter happy for an endless number of rounds. I also addressed the charging system that would allow us to run the electric water pump and fan as much as necessary to control the temps. Planning for these types of situations during the initial build is the time to implement these ideas. Many people came up to me toward the end of the day and couldn't believe the amount of runs we had made on the car, and that it was still happy.

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The next time you're dreaming up your next project, make sure you're honest with yourself on what the car must do-it'll save you money in the long run. There is nothing worse than completing your build only to discover that one system won't keep up with the rest of the package. I hate going back and reworking the build just when you're done with it. We build them to race them, drive them, and enjoy them.

Wheel Art
Q: Can you tell me the correct paint color and/or code for the '71 and '72 SS Chevelle Rally wheels and where I can buy the paint? Also, is the paint the same for the '71 and '72 SS El Camino? I have tried several paint restoration parts companies and been given different paint colors from them. Thanks for your help.
Jim White
Via email

A: The GM Rally and SS wheels that were silver were painted in Argent Silver. The SS Chevelle and SS El Camino wheels were painted the same. The Corvette and Camaro Rallys were completely painted in the Argent Silver, and the SS Chevelle wheels had a mix of Argent Silver and Charcoal Gray. Then you have the five-spoke Camaro SS wheels that were completely painted in a Charcoal Gray.

Check with Eastwood for all your refinishing needs to match the exact reproduction color, including Argent Silver Rally Wheel paint, PN 10001Z for a 12-oz rattle can, and the Charcoal Gray, PN 10003Z for a 12-oz can. Eastwood also offers the Argent Silver in quarts if you're looking to spray it out of a gun.

Hope this gives you the info to refinish your wheels properly. Those are some of the nicest wheels GM ever put on a muscle car. We've had Chevelle SS wheels, Vette and Camaro Rallys, on just about everything that we've owned over the years. The Chevelle SS's were our favorite.
Source: eastwood.com

Little Deuce
Q: I've been away from working on muscle cars for quite a while. I purchased a '67 Chevy II with a 230 L6 and a Powerglide. My 5-year-old Goodwrench 350 has less than 1,000 miles on it. Once I purchase the adapter kit with the oil pan, mounts, pickup, and pump, will this fit into my car? I ask because the original 283 and 327 blocks have the recessed oil filter boss. I'm concerned that after I spend the money it will be a waste. The engine also has the '67-72 Chevy truck swept-back ram horns-in other words, they don't dump straight down like a Vette. It looks like they will clear the front suspension. Am I right?

Can I fit my 186 fuelie heads on this engine without a problem? I want to go with a Comp Cams Thumpr Cam, 186 heads (April '70 casting), an Air-Gap manifold, and a 600-cfm carb. What cam should I go with? This is just for cruising, by the way.
Erik
Castle Rock, WA

A: The base GM Goodwrench engine is a strong foundation for building a mild-performance small-block. Yes, the Chevy II small-blocks had a recessed oil filter pad to allow the exhaust head pipe to run under the oil filter. This gave the clearance necessary for the suspension and ground clearance. You know, the old 25-pounds of poop in a 5-pound bag! The exhaust manifolds you're referring to are, as you stated, for Chevy pickups. These manifolds will not clear the suspension. Chevy II production exhaust manifolds won't fit the Goodwrench block because of the oil filter location, but there are headers out there that will clear the oil filter in the standard small-block location. Hedman makes a nice set of compact, in-frame, full-length headers (PN 68160) that will work with the standard oil filter location. They feature a 11/2-inch primary pipe and a 3-inch collector. The headers require that you use a 153-tooth flexplate or flywheel to keep the starter up against the block.

The Goodwrench engine will love your 186 casting fuelie heads. The 64cc combustion chambers will raise the compression from the pedestrian 8:1 up to a little over 9:1. This will really help with your camshaft selection. For a nice cruiser camshaft, we would go with the smallest Thumpr camshaft Comp offers (grind number 279TH-7, PN 12-600-4). It specs out at 227/241 degrees duration at 0.050-inch tappet lift, 0.479/0.465-inch max lift, ground on a tight 107 separation angle, and installed at 102 degrees intake centerline. This camshaft has a ton of overlap and will give you a very authoritative idle sound. Let's just put it this way, with performance mufflers your neighbors will know when you come home!

Good luck with your little Deuce project. The '67s are my favorite of the early Shoeboxes. I have really cool memories of these from my high school days. Helping my buddies swap out parts and hauling ass around. Have fun!
Sources: compcams.com, hedman.com

G-Bodies That Fly
Q: I'm looking for help with picking a cam that would be both streetable and track worthy. The setup is an '87 Monte Carlo SS (full interior) with a 3.90:1 gear, a TH350 trans, and a 3,200-stall converter. The engine is a stock LQ4 6.0L with an Edelbrock dual-plane LS1 intake, retrofit headers, a 750 Holley double-pumper carb, and an MSD 6LS. The exhaust will be a 21/2-inch with an X-pipe. I look to drive the car 300-500 miles a month and take it to the track twice a month. I've contacted a few different companies with mixed results. I was looking at an old article with the GM Hot Cam, which yielded some pretty nice numbers. This was only the engine alone though.

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

A: Either of those two donor vehicles will work. All the '78-81 A-bodies and '82-88 G-body passenger cars have the same 108-inch wheelbase. The '78-87 El Caminos have a wheelbase of 117 inches. We'd use the '84 Cutlass if it's in good shape; any of the subtle upgrades made over the years would be intergraded into the later-model frame. Also, the late '70s is when The General converted over to robotic welding. Our '79 Malibu Wagon race car frame has some really nasty welds. By '84, they should have gotten much better.

Be very careful when swapping out the frame. With the perimeter frame in the G-bodies, you only have the rocker panels to lift the body off. Make sure you have very secure and braced stands before rolling out the chassis. Also, get the replacement frame back under the Monte as quickly as possible. Finally, replace all the body mounts while you're at it. The rubber mounts degrade over time and really compress. You can replace the mounts with polyurethane mounts from Energy Suspension. This really stiffens up the car and gives you all the body mounts, core support mounts, and hardware. Again, be careful. We've replaced the bushings before and you don't want to get your hands caught between the frame and body.
Source: energysuspension.com

B-Body Boogie
Q: I have a '69 Impala two-door Sport Coupe that has been tortured by 41 Wisconsin winters. The body is stored on a trailer in a barn and the rolling chassis is the only part remaining in my garage. In the near future I'm going to start working on the chassis. I don't want the car to ride like a family car. With a 383 stroker and a TH700-R4 turning the rear wheels, I'd like the rear end to be able to perform as well as the front end of the car. Everything I've read tells me the only real difference between what I have and an SS is suspension is that the SS is stiffer. What do I need, or who do I need to see to get my rear end to handle like the true SS Impala?
Kevin Bieber
Via email

A: Yes, the SS cars had stiffer springs. This gave the car a better feel and less of a yacht-feeling ride. For performance usage, you'll want to do a major upgrade both in the front and rear. Get in touch with Global West Suspension, which has been building quality suspension components for GM vehicles for over three decades and offers upper and lower control arms for both the front and rear suspension. Global has specific performance front and rear springs engineered for your B-body and a very nice tubular adjustable track bar and relocation kit for proper geometry. Finally, the antisquat kit relocates the rear upper control arms to change the geometry in the rear, increasing or decreasing the amount of downward force on the rear tires. Antisquat is a fast way of improving performance without doing serious modifications to the vehicle.

All major builds like yours take some time. Be patient and enjoy the time with your car. You will appreciate it even more when you're done. Good luck.
Source: globalwest.net

Quench Or Not To Quench
Q: I have a question on combustion chamber quench. I am currently building a 406ci small-block for my street rod. The car weighs about 2,600 pounds and is equipped with a Turbo 350 trans, a stock converter, a 2.79:1 rear gear, and 28-inch-tall rear tires. I drive it just for pleasure and going to rod runs.

The 406 is balanced, has stock 5.565-inch Keith Black KB159 pistons with a 12cc dish, Edelbrock Performer RPM heads (64cc), a Performer RPM intake, and a 600-cfm carb. The static compression ratio is about 10.3:1. I'm also using a Comp Cams XE256H-10 hydraulic flat-tappet cam (212/218 duration at 0.050) as recommended by the "cam help" service. At TDC the pistons measure 0.022 down in the cylinders. This, coupled with the Fel-Pro 1014 coolant control head gaskets (0.039 compressed thickness) adds up to a quench of 0.061. Would you deck the block, and if so, by how much? Do you have any other ideas?
George L. Flanagan
Lilburn, GA

A: Tight quench area is always a good thing. It gives you mixture motion that promotes more efficient combustion. Is this always the case? In our LT4 small-block we had cut the block down to achieve 0.040-inches of deck clearance with a 0.026-inch GM composition head gasket. Well, if you remember our washer story (we're not going to repeat it!), we had to take the LT4 apart and replace the pistons, and we clipped the deck for a cleanup. After cutting several thousandths of material off the deck we had a set of Cometic MLS head gaskets made up at 0.030-inch to maintain our 0.040-inch of deck clearance. To make a long story short, the head gaskets came in as a Gen I design, and my LT4 is a Gen II with reverse-flow cooling. No fault of Cometic! We found this error on a Saturday and had to get the engine back together for a points race the next weekend. We ran down to the local auto parts store and bought a Fel-Pro Head Set with Perma-Torque head gaskets. These gaskets were the standard production thickness of 0.051-inch. So the deck clearance went from 0.040- to 0.061-inch. The next weekend we expected to lose a ton of on-track performance. Guess what, it didn't lose even a hundredth!

What happened here? Well, we believe the LT4 heads have a really good combustion chamber, and the intake port gives the air/fuel mixture a good ride into the combustion space. The increased deck clearance didn't affect the burn. This is not always true. With poor combustion chamber designs, like early iron heads and smog designed heads, they need all the help they can get. This is where you see gains from tight deck clearances.

Now, for your RPM heads and your specific application. We think the performance we've seen out of these cylinder heads shows that they have an active combustion chamber and good intake ports. Also, you already have 10.3:1 compression. If you reduce your deck clearance down to, let's say, 0.040-inch, you will reduce your cc's by 4.44. This will raise your compression up another 0.3 to 0.4 CR. This, with your relatively short camshaft and high rearend gears, is just looking for a spark knock issues.

If I were you I would leave your deck clearance alone and enjoy your lightweight street rod. The torque that this engine will make will give you quite a thrill when you stand on the throttle. Cutting the deck for a few extra horsepower really isn't necessary for the use of the engine. Enjoy your cruiser.
Source: cometic.com

H2O By Volts
Q: I've been looking at putting an electric water pump in my '64 Corvette. They appear to have several advantages over a mechanical pump: water flow at low rpm, freeing up horsepower, and no cavitation at high rpm. I am just concerned about reliability and suitability for the street. I drive this car daily, weather permitting, and it's hard to knock a mechanical pump for reliability, since it's been doing the job since day one. I have a 377 small-block in the car, with no air, and a flex fan backed up by an electric fan for sitting in traffic. I'd appreciate your help, as these pumps are pricey and there is not a great deal of info out there I have been able to find.
Tony Bassignani
Charlottesville, VA

A Using electric pumps on the street has been only possible for the past 10 years or so. Harold Meziere and family builds one of the finest pumps for racing, and offers pumps with reliability to match street driving. My dad has a '55 Del Rey with a 468 big-block that has always been a chore to keep cool in traffic during the summer months. Cruising at low engine speeds with the Vintage Air running to keep he and Moms cool would kill them. About five years ago he replaced his crank-driven water pump with a Meziere remote electric water pump, which has worked flawlessly ever since. He went with the remote design because of the close proximity to the radiator with a puller electric fan on the backside of the radiator. He has made several trips to Northern California from SoCal without a problem with reliability or heating issues.

For your Corvette, we'd recommend one of Meziere's block-mounted 55-gpm pumps. The electric motors on these are rated for 2,500 hours of trouble-free service. Knowing Harold as we do, we'd say this is a conservative rating. The pumps are a work of art in both manufacturing and engineering detail, and they're available in chrome; polished aluminum; red, blue, and black anodized finishes.

You should realize around an 8hp gain at the rear tires just from the pump. If you go with a full electric fan arrangement, you will see even more gain over your flex fan. Going electric also really cleans up the front of the engine.
Source: meziere.com

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

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