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Chevy 383 Turbocharged Engine Build - Performance Q & A

Kevin McClelland Nov 1, 2009
0911chp_01_z Chevy_383_turbocharged_engine_build Frequently_asked_questions 2/2

For Safety's Sake
Every two years we get to do the seatbelt boogie in our race cars. Some people moan and complain that NHRA and other sanctioning bodies are getting kickbacks from the belt manufacturers. Well, I'm not one of them. Every time I belt myself into my roadster, I trust those belts to keep me within the safety zone of my 'cage and chassis. Sure, most door cars (enclosed) don't get much sunlight on the belts, but our open cars and dragsters have direct sunlight deteriorating the nylon webbing. The last thing you need is a belt failure as you're slamming into the guardrail-or worse, a racer coming into your lane.

One suggestion to make the belt swap a little less painful is buying a new set the next time you need your belts inspected and rewebbed. This will give you an extra set of hardware so you can have them rewebbed before the two-year replacement date and swap them right in. Many cars require disassembling the car a bit to install the belts. Mine is one of them.

As for other safety equipment, like transmission shields, flexplate shields, and flexplates themselves, I think the sanctioning bodies are a little over the top. It's pretty tough for a piece of aluminum shielding that wraps the transmission to wear out! Well, I'll get off my soapbox for now.

A reader wrote in this month asking at what e.t. breaks the NHRA requires specific safety equipment. It varies based on the type of car. When we talk about hardtop (nonconvertible) cars and trucks, you can run down to 14.0 seconds before you need a Snell 2000-or-newer helmet. The next break will be 11.50 seconds in the quarter-mile before you need to install a rollbar and aftermarket seatbelts. You can run all the way down to 10.0 seconds with a rollbar if you haven't modified the firewall or the floorpan with other material. You can run all the way down to 11.50 without a driveshaft loop if you're running on street tires, but if you swap out and run slicks you must run a loop once you hit 14.0. Once you hit 11.0, you must install an automatic transmission shield and aftermarket rear axles.

When you talk about open cars, like convertibles and roadsters, the rules get much stricter. A rollbar and aftermarket belts come in at 14.0 seconds. Also, driver's safety gear steps up with a 3.2A/1 SFI-approved jacket, arm restraints, and gloves when you run 11.99.

This has been a quick overview of what you'll need before you take your fast street cars out to the track this summer. Check on NHRA's website ( for more information and regulations based on the e.t.'s you project for your toys. Be safe so you can be around to read more tips!

Oils Well That Ends Well
Q: I'm building a 383ci engine with a Turbo kit I made. I'm using an Eagle bottom-end assembly, an ARP bolt kit, and Edelbrock heads. I don't know which bottom end to go with when it comes to windage tray. Should I get one that bolts to the main caps or one built into the oil pan? Since the oil pump will also feed the turbo, I'll be going as big in the oil pan (8-quart) as possible. What are the pros and cons of both, and what would you recommend? The turbo is going to be making no more than 10 pounds of boost. Thank you.
Kevin Nesbit
Milwaukee, OR

A: Every time we have delved into windage trays, we found that they are basically worthless until the engine is above 6,000 rpm. This is in the horsepower department on an engine dyno. As for oil control, on the street or an oval or road racing track, they have an entirely different purpose. If you didn't have trays in the pan to control the oil under heavy braking or cornering, you'd run the oil pump pick-up right out of oil, and heavy bearing failure would be quick to follow.

Now, which type of tray to run? When you add too many components (parts) in the crankcase space (pan), it can cause more problems than it's worth. Simple flat trays with louvers give the cylinders plenty of space to breathe from bay to bay and get the oil away from the rotating crankshaft. They also keep the oil in the pan where it needs to be, around the pick-up. Check out the Solid Louvered Windage Tray (PN 32100) from Milodon. This contoured tray helps scrape the oil off the rotating assembly and direct it back into the sump of the pan. Next, look at the Pan Baffle (PN 32500) to mount under the factory oil pump and prevent the oil from climbing up the back of the pan and into the rotating assembly during hard acceleration. Finally, pick up a set of the Adjustable Windage Tray Studs (PN 81150). These allow you to adjust the height of the tray in relationship to the crank and rods.

This will give you a solid foundation for your oiling system, prevent starvation from hard driving, and keep the unwanted oil in the crankcase space away from the crankshaft. Good luck with your homemade hairdryer.Source:

Outside Help
Q: In your Apr. '09 column, reader Henry James asked about a brake pedal that goes to the floor in the parking lot. I had the exact same symptoms in my '55 Chevy for nearly two years until I hit the back bumper of a Toyota in a parking lot. I refused to drive the car until I found the problem.

I had installed a short rear axle and moved the springs into pockets in the frame. That shortened the outside dimension of the rear tire to the point that the fronts looked too wide. So I ordered some shortened tubular upper and lower control arms to tuck the fronts in 1 1/2 inches per side. Several years later when the car was complete, this brake problem came up. I did everything James did, plus I removed a new power brake booster and master cylinder and installed a master cylinder for manual disc brakes, thinking the ZZ3 crate motor was not developing enough vacuum at idle to supply the power booster. Same problem-and then the Toyota shut me down.

After much searching, I found the problem accidentally. With the car up on stands under the control arms to duplicate the suspension height, I turned the steering wheel hard left, like I was turning into a parking space, and bingo! The left front caliper hose bolt hit the outside of the frame and pushed the caliper out, which backed fluid up into the master cylinder and caused a gap between the brake pad and the rotor. Then when I applied the brakes, the pedal had to push the caliper piston back out and the pedal bottomed out before the pads made contact with the rotor. The next time I applied the brakes I had a full pedal. I checked the right side-same thing. The solution was to exchange the calipers for some with a hose outlet a little lower and more toward the rear so the boss wouldn't hit any more.

James might have a different front suspension but the same problem. Just check for caliper interference when the wheels are turned to be sure.

Your Q&A column is the best of any mag I read. Keep up the good work!
CJ Lane
via email

A: Your point is well taken. Anytime you've modified suspension and braking systems, checking for clearance at all ride heights is essential, even if you need to remove the springs from the suspension and articulate the suspension at all ride heights to ensure clearance of all components like brake lines, e-brake cables, driveshaft, and U-joints.

Thank you very much for your response. You've saved many readers from big trouble and possible injury. We all need to look out for one another.

Rearend Relief
Q: I have a '63 Chevy Fleetside truck in original condition, and I need to know some things. What rearends out of newer trucks are interchangeable without a lot of hassle? I'm putting a 700-R4 in it, bolted to a 355. I am looking for something with a good gear for highway use. I'm currently using a 10-bolt rearend. If I just change the third member, what gears should I go with? Any answers would help.
Shane Fishel
Mooresville, IN

A: You've really hit a soft spot in my heart. When I was 16 years old we used a '63 Chevy 1/2-ton Fleetside to tow my dad's race car to the track. This was a $600 truck with a 292ci six-cylinder and three on the tree. After breaking my first two cars I moved on to the truck because Pops figured I couldn't break a truck. Well, the three-speed Saginaw wasn't long for this world! I got really good at dropping out the trans and swapping in a new First gear. I went completely through this truck, restoring it, and finally swapping in a 327ci and a Muncie four-speed in the later years.

The '63 model came with either leaf-spring rear suspension or the famous truck-arm suspension that to this day NASCAR uses in its rear suspension. For many years it actually used the factory truck arms in the race cars. None of the later-model 10-bolt 8.5- and 8.625-ring-gear 1/2-ton truck rearends will bolt right in. The leaf-spring mounting pads are in different locations. It would be very easy to cut off the factory pads and weld some new ones in the proper location for your springs. If your '63 is truck-arm suspended, you'd need to cut the factory pads off the original rearend housing and weld them to the late-model housing. It may prove quite tricky getting the original pads off the housing without damaging them too much. Also, the truck-arm design uses a Panhard bar to locate the rear axle from left to right. You'd need to fabricate a bracket to attach it to the new housing.

You stated that you have a 10-bolt rearend and a drop-out pumpkin. This is the earlier-design rearend and quite possibly a 3/4-ton design. Finding gearsets for this early design will be tough. Check with Randy's Ring and Pinion for direction on a gearset.

Swapping in a 10-bolt 8.5 from a mid-'90s-or-later truck is a piece of cake. As for gearing, we'd look for a 3.42:1 rearend to drop in. This is a great ratio that will balance performance and freeway manners. Trucks have larger-diameter rear tires than passenger cars. This, in combination with the 0.70 overdrive of the TH700-R4, will really bring the engine speed down on the freeway cruises. Check out Speedway Motors for components to make your rearend swap a snap: weld-on spring perches that will match right up to your housing and U-bolts to hold it in place. Make sure before you strike an arc with the welder that the axlehousing is centered between the framerails and that the pinion angle is pointed down around 2 degrees more than the driveshaft angle at a loaded ride height. This will keep your U-joints happy and allow for the full range of suspension travel.Sources:,

Q: I have owned my '78 Chevrolet Malibu since new. It still has the original 305ci engine in it for now, but I have a built 383 small-block to install later this spring. Also, I rebuilt a TH350 transmission over this past winter with all the good stuff and already installed this tranny in the vehicle with the 305 engine, mostly to make sure it functions properly. The good news is that there's no problem with the install, but I cannot get the column shifter to work with the TH350 trans. I want to keep the column shifter since the car is mint (only 40,000 original miles). The original TH200 seems to have a slightly different "rooster comb" for the detent positions than the TH350. I can get it to go into the L1, L2, D, and N positions, but R and P cause the column shifter to hang up and not allow it to get to Park. The detent in the trans will go to Park, but the lever will not, and this creates a problem removing the key from the lock. Is there a modification or part for the column that will get me where I need to go?
Jeff Stec
Wapwallopen, PA

A We've been around since dirt was invented but have never heard of a "rooster comb!" The OEMs call the transmission detents and the display in the dash the PRNDL, pronounced prindle. The TH350 and TH200 have the exact same spacing between gears. When you adjust your linkage, you should always adjust the Neutral position to be dead accurate. This will give you the best chance of reaching all ranges of the transmission. You didn't mention if you retained the factory cross-shaft from the framerail to the shifter shaft bracket. This cross-shaft and the arm lengths set the ratio between the column arm and the distance that the shifter shaft must rotate to achieve all ranges of the trans. This shaft may need some modification to connect directly to the TH350 because the trans is slightly wider than the TH200. You could find a cross-shaft in a wrecking yard from any G-body GM car with a TH250 or TH350. This should give you a direct fit.

Give your linkage another once-over. You're very close and should be able to adjust out your issue. Good luck with your engine swap, and have fun with all that newfound power!

Crank, Fuel, Add Spark
Q: I have a '74 Nova with a 406 that's topped off with an Edelbrock Vic Jr. aluminum heads and intake and roller rockers. and I'm pretty sure it's around 12.5:1 compression. It has quiet geardrive and a new Quick Fuel 750 carb with 74 primary and 84 secondary jets and a factory HEI distributor. I don't know anything more about the engine. I bought it from my dad, and he got the motor from a guy in the trading post. The cam is big and has a really rough idle, and I've been having trouble getting it timed. I've got it at about 36 degrees now because that's where a friend told me to start. My main problem is I keep getting gas in the oil. What would cause that? Do I need an MSD ignition? If so, what kind? I've also got a starter trouble-the mini torque starter gave out.

Love the magazine, and thanks for any help!
Joe Oatman
Cuba, IL

A: Fuel in the oil can be caused by many different problems. You didn't state whether you were running an electric fuel pump or a block-mounted, diaphragm-type manual pump. Very rarely have we seen the diaphragm in the pump fail and leak fuel into the crankcase. It's rare, but it can happen.

You need to completely troubleshoot your Quick Fuel carburetor; they're very high-quality carburetors, but you don't know who has had his hands on it. First, make sure you're getting clean fuel at the proper 6 psi of fuel pressure to the carb. Next, the float level must be adjusted to ensure that you're not leaking fuel over the main boosters. If the floats won't adjust properly, it's possible they've been damaged from handling and they are taking on fuel. Finally, if the carburetor is equipped with power valves, you must check to see that the diaphragms are not damaged from backfires. Overfueling the engine and getting enough fuel past the rings to have fuel in the oil is very damaging.

Your jetting isn't out of the question for a rowdy little small-block with a lot of camshaft. This would be a good baseline until you can straighten out all the other tuning parameters; 36 degrees of spark is another good baseline for your engine combination. We wouldn't increase the spark advance until you figure out your overfueling issues.

A stock HEI was never designed to keep up with your engine combination. We'd move to a Digital 6-Plus MSD Ignition Controller (PN 6520). This features launch and high-side rev limiters, a single-stage retard for nitrous use, and a start retard to ease pressure on starters, flywheels, and the engine. All the features are built in and adjustable right on the box with simple rotary switches. This will give you the spark energy you need to keep the fire lit under high cylinder pressures and clean up the idle with the multiple sparks over 20 degrees of crankshaft rotation at idle. When you install the Digital 6 you'll need to install an HEI coil (PN 8225). You can trigger this box with your HEI distributor or step up to a MSD Pro Billet Distributor (PN 85551). If you go to the MSD distributor you will want to run the Blaster HVC coil (PN 8252). This will give you a complete matching system that will light your fire.

Finally, when it comes to starters, you get what you pay for. There is nothing worse than getting late in the rounds of a race or at a cruise night with a hot starter and it won't start. There are many good mini starters on the market, but as we've said in the past, we really like the permanent magnet gear reduction starters that are factory equipment on GM vehicles. These lightweight starters are very powerful and have full support at the end of the pinion gear. For a 14-inch, 168-tooth ring gear, check out PN 9000852; for a 12 3/4-inch, 153-tooth ring gear, order PN 10455709. We've used these starters on race cars for over 13 years without failure. Remember, these have passed durability testing for over 100,000 miles. Are any of us going to put that kind of mileage on our hot rods or race cars?Sources:,,

Chip Shift
Q: I have a '70 Chevelle with a 383 and a TH200-R4 transmission. The trans has a B&M shift-improvement kit and a 2,200-rpm lockup converter. When the trans is manually shifted, it takes a long time for the shift to occur. It does shift firm, but late. When I was running a TH350 trans it shifted almost instantly when manually shifted. If I try to shift the TH200-R4 at the same rpm as the TH350, the engine ends up hitting the MSD rev limiter. What can be done to improve the delayed shifting of the TH200-R4?
James Workman
Mount Sterling, KY

A: You know we're going to give you a snarky response, like shift the thing earlier to keep it out of the chip! If you've been playing this game for a while you've noticed that the TH350s and TH400s shifted very positively and right when you moved the shift lever or handle. The later-model TH200-R4s and TH700-R4s have their own unique shift timing caused by a complex valve body and fluid pressure management. The earlier transmissions used a very simple governor and vacuum modulator to get throttle pressure. The later overdrive transmissions use a governor, but a cable-operated throttle pressure valve to signal load to the trans. We've never seen a quick-shifting (by the shift handle) overdrive-type transmission. The 700s seem to have a delayed 2-3 shift, and the 200s have a delayed 1-2.

Transgo has been in business since 1959. These were the very first shift kits we installed back in the '70s, and the product line is still great. Transgo offers a shift-improvement kit (PN SK 200-4R) that it claims will correct 3-2 cutloose, 1-2 slide or slide-bump, wrong gear starts, downshift clunk, rough 2-3, late shifts, early shifts, and kickdown delay. Yes, your B&M shift kit should have helped with the delayed shift; however, the more we looked into this problem, the more Transgo came up as the place to turn for help, such as with its reprogramming kit (PN 200-4R-HD2), which is more a race calibration. This may be too aggressive for what you're looking for. It still retains full automatic programming for street use.

Either lower your shift rpm to keep it out of the chip, or install a higher rev limiter (just kidding). We've always had to shift the overdrives about 500 rpm early. It's been more than once that the El Camino was north of 7,000 rpm when the TH700R-4 finally went into Third gear. And each time it did you held your breath. Happy shifting.Source:

Round Out The Package
Q: I'm trying to get more pulling power out of the 5.3L engine in my '01 Chevy Tahoe. I have changed the air filter to a cold-air package, replaced the spark plugs, and upsized the spark plug wires. It does run better with these changes, but not as much as I hoped. I pull a small trailer, and on some hills it's just a dog! Thanks.
Bob Trapizona
via email

A: Your best bet with minor bolt-ons is to finish out the standard performance package. You are now getting more air into the engine, but the exhaust is still plugged up. Installing a nice after-cat exhaust will free up the backpressure and round out the easy airflow increases to your engine. Check around for the sound and quality you like. Borla, Flowmaster, and MagnaFlow all build a high-quality exhaust system that will free up your exhaust flow. They each have a different exhaust note and tone. Check the manufacturers' websites for audio and video clips of their exhaust systems.

Now that the exhaust has somewhere to go, you can throw a better tune-up at the engine. Check with Hypertech for information on the Power Programmer III. This trick handheld device plugs into the diagnostic plug under your dash, and with some simple yes/no questions you can pick up real power and fuel economy. The programmer allows you to adjust the tire size, fuel type, speedo corrections, shift points and firmness, rev limiter, and top-speed adjustment to tire quality, and it reads and clears diagnostic trouble codes. A stock Tahoe with a premium fuel calibration had gains of 17 hp and 24 lb-ft of torque at the peaks. This will only complement your cold-air intake and exhaust system upgrades.

Between the exhaust and programmer install on your truck, I'm sure you'll like the extra 20 to 25 ponies they will free up. This should make easy work out of the hills with your small trailer.Sources:,,,

Technical questions for Kevin McClelland can be sent to him at



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