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April 2010 Performance Q&A

Tom Truty Jan 27, 2010

Cool Trick
Have you ever tried something and you just couldn't believe it worked? I've been drag racing for way too many years, and this one really opened my eyes. As you all know, we've been trying to race Stock Eliminator for a couple of years now. Making enough power to push our '80 Malibu wagon into the 12s with a very restricted 305 is tougher than it seems. When we started this project, I never thought that making enough power was going to be the issue. Making the chassis work correctly or getting the rolling resistance down to make the car quick was what I thought was going to be the tough part.

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Back in 2007, we rolled out for our first race in Stock at the Winternationals. We ran 0.25 under our index, and I was very happy with that for our first time out. Well, after several engine rebuilds (and I'm being kind), we hadn't seen much improvement. What we had seen was that when the weather turns bad (high temps and density altitude) the car really slows down. Most of our testing has been at Auto Club Speedway in Fontana, California. The natural altitude is around 1,200 feet and the barometric pressure is very low for our altitude. My son, Daniel, and I felt that if we could run the index here at Fontana, we'd be fine to go up and run the Divisional race in Bakersfield, California. I looked back through my log books from Bakersfield for the past five years and found that the air hadn't gotten anywhere near as bad as we've been seeing at Fontana. As climate change would have it, the density altitude at Bakersfield this year was in the 4,200-foot range with the temps tickling around 102 degrees.

The wagon was right on the index for the first two timed runs, giving nothing to dial with. I'd tried everything, including draining out a quart of engine oil and taking out the last 8 pounds of weight, putting us dangerously close to minimum weight. This is when my good friend and fellow racer Jody Lang stepped in and asked what temperature we were running the car. I told him we were pulling out of the head of the lanes at 130 degrees F. He said "What do you think this is, a bracket race? Cool that thing off." I thought 130 was cool. We'd normally run our bracket package in the 150 range, pulling out. For the final run we cooled the engine down to 100 degrees (tough when it's 102 outside) and sprayed down the intake manifold with ice water. Daniel pulled out for his final timed run and the car picked up 0.20 second from the prior two runs! I was very surprised that the temp change made that much of a difference. I was very skeptical with the gain for first round and dialed him up a little to be safe. With the same cool-down procedure we were rewarded with a 0.23 under 12.92 e.t.

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Well, contrary to how the saying goes, you can teach an old dog new tricks. Thanks to Lang we were able to make it into the field. I would have never believed it if I hadn't done it myself.

Diaphragm Dilemma
Q: I am a subscriber and am trying to rebuild the Holley carb off my '60 Corvette. I doubt any work has ever been done on the carb; I have owned it since 1984 and have not worked on it before. I've been following the steps as described in your article on how to rebuild a Holley carb, but I decided to also rebuild the vacuum diaphragm. Do you have a recommendation on where to find info on rebuilding the vacuum diaphragm? There is a little ball bearing that came out after I disassembled it, and I don't know for sure if I'm putting it back where it belongs. Also, the diaphragm holes do not seem to align properly, regardless of which way I turn it to reinstall it. Thanks for the help.

Tom Richards
Flower Mound, TX

A: Those pesky secondary diaphragms can be a real pain to reinstall. Are you replacing the original diaphragm with a new one? With the age of your carburetor, it's virtually impossible to reinstall the original one. They shrink over time and it's tough even for a pro to get them back into place correctly. We've got a few tips for you to make the job easier.

First of all, go to Holley's website and download the Installation, Tuning, and Adjustment manual for the 0-3310-S carburetor. We're sure your carb is a different number, but the tuning and adjustment of the vacuum secondary diaphragm is the same. This instruction manual has a section titled Vacuum Operated Secondary Tuning. This has the instructions, photos, and tips on disassembling and reassembling the secondary diaphragm. It has a photo where the small check ball goes. There's even a nice tip on how to keep the secondary diaphragm in the proper shape for assembly.

A couple of tricks we've learned over the years is to use a bench vise to help in assembly. To put together the diaphragm assembly you really need three hands. Slide the new diaphragm into the base of the secondary housing. Using the vise, clamp the shaft of the diaphragm at the proper height to keep the diaphragm at the correct shape to match the base. Then, when installing the diaphragm cover, use a little white grease on the screws to prevent them from grabbing the rubber diaphragm and damaging it. If you don't use a little grease, the screws grab the diaphragm, twisting it out of shape and sometimes tearing the rubber.

Between the instructions online and a few simple tips, you should have your carb together in minutes. When installing your fresh rebuild, start with float settings and then get the idle fuel screws close. Set your idle speed and then do your final tune on the idle fuel screws. Doing these steps in this order will give you many years of great service from your Holley carb.


Quest For A Greater Understanding
Q: Hello! I have been a longtime reader of this wonderful magazine, but I suffer from a lack of real knowledge and comprehension when it comes to the finer details of how to design street or race engines. I have dozens of books and even some videos-and have read them all- but they seem to lack that next level I seek. Do you know of any books that can help me, aside from SA books? Or even better, some videos other than the Power Building videos? Any help or a point in the right direction would be much appreciated.
Thank you!

Ben C.
Bloomington, IL

A: Finding truly accurate data can be really tough. The Internet can be great, but you have to be very careful who you listen to. Anyone with a keyboard can present a very good line of info that could be a bunch of hogwash. We can think of a couple of books you need. Reher-Morrison racing engines released its Upper and Lower Engine Assembly books about eight years ago. These hold the secrets that only professional engine builders knew and used. They are both very informative and down to earth with their explanations and theories. Well, Reher-Morrison has just improved these books by taking more than a year revising and consolidating them into its new release, Championship Engine Assembly. The book is huge, containing 392 pages of information and over 600 detailed photos and graphics that show you the right way. Several colleges recently selected to feature it in their race engine technology programs, yet you'll find it easy to read, with simple terminology in carefully organized steps. Check with Reher-Morrison and pick up a copy of the book. You won't be disappointed.

After that, if you want to take your skills to the next level, check out its Racing Engine Building School online. Reher-Morrison brings you right into its engine building facility and teaches you the ins and outs of professional racing engine building, with small class sizes and one-on-one instruction. Let us know when you're going-maybe we can get a combo deal!


Synthetic Leak
Q: I have a 305 bored 0.060-inch over with an Edelbrock carb and manifold, large-valve heads, 9.5:1 pistons, and FlowTech headers. My problem is a persistent oil leak in the front of the engine. I used oil dye and UV light to find this leak. To date, I have twice replaced the oil pan gasket-once with a four-piece with sealant and once using a one-piece with sealant. Also, I have replaced the timing cover gasket, a new Chevy timing cover, and a crank seal.

Still the leak is there. I have also checked to ensure I haven't left any bolts out of the front of the engine for accessories. I recall an article you wrote in CHP concerning synthetic oil and leaking. Can you shed any light on this problem? Thanks for helping me in my slippery situation!

Bob Kay
Via email

A: Keeping synthetic oil in the pan has always been a challenge. If there is any chance of a leak, this slippery stuff will find a path.

We've been using a four-piece pan gasket forever. When Fel-Pro released the one-piece silicone pan gasket for the early small-blocks we tried one on the engine dyno. It had a few slight seeps that would creep up over time. When we built the engine for our Stock Wagon we used a one-piece gasket so when NHRA asked us to tear it down for tech inspection, the pan would be easy to drop and replace. It has had some type of leak on every rebuild. On the last rebuild, we decided we had used the gasket too many times and that's why it was leaking. Installing a brand-new one-piece gasket, and making sure everything was straight and true, it still has a very slight seep from the front of the pan. Next time we're going back to the trusty four-piece gasket.

As for your situation, you've replaced everything on the front of the engine. The only thing you haven't mentioned is whether the leak is coming from the pan seal or the front crankshaft seal. You should have been able to see the leak path with the UV lamp. You replaced the front cover seal, but you didn't mention the condition of the sealing surface of the damper. If the damper is worn from years of service, the front seal won't have a chance. You could replace the damper or go with an easy fix: Fel-Pro's Harmonic Balancer Repair Sleeve repair kit. This is a very thin steel sleeve that presses over the damper sealing area, which gives you a fresh sealing area. These kits are very inexpensive and have saved many a damper. Pick one up for a small-block under PN 16202 if you need to tune up your damper.

One last thought, you said you replaced your front cover. The groove in the front cover that the oil pan gasket seals into is welded to the front cover. If this weld isn't perfect, there could be a slight seep between this groove and the front cover. This would be asking the pan gasket to seal on the front face of the gasket, not in the proper plane in compression from the pan. This is a long shot, especially since you have replaced the front cover and had a leak with both.

Hope talking through your problem has given you a couple of ideas. There is nothing worse than pulling into your buddy's driveway with your car and leaving a calling card. Not to mention what it does to the underside of your Camaro. Good luck sealing up your small-block.


Suspension Questions
Q: I bought a '70 El Camino as a rolling bucket of parts. I haven't done a full frame-off, but I did bring the front down to the framerails and firewall. Reassembly was done with a new 350, and I changed all the joints, bearings, and bushings. I used what torque specs I could find from the manual, and the only modifications I made to the suspension was to cut the springs and add 18-inch rims. This was definitely a budget build, but once the car would roll again I went to a suspension shop for an alignment and paid them to go through my work. Then I moved on to the hundreds of other issues the car has.

A couple of weeks ago, after about 3,000 miles of road time, I was in a parking lot when I heard and felt a suspension noise. I found that the three remaining bolts on the upper control arms were all hand loose. Fortunately, the missing one was on the trailing side so I didn't snow-plow-or worse. That said, I obviously didn't cover all my bases. Should I have used Loctite on everything, or do I just need to perform periodic inspections?

Kelly Williams
Via email

A: We're assuming you lost one of the upper control arm shaft bolts and washers that attach at the end of the shaft that captures the upper control arm bushing. Did you use factory-style bushings or aftermarket polyurethane ones? The factory bushings have serrations on the inner sleeve that cut into the control arm shafts and into the washer. The bolts that retain the washer are 3/8-inch 24 fine-threaded Grade 8 fasteners. These bolts from the factory have split lock washers under the head of the bolt, between the washer. You should have torqued these fasteners to 45 ft-lb. The factory spec assumes that the threads are clean and lightly lubricated. If you didn't torque them properly, they are notorious for loosening up as the suspension jounces up and down. Using Red Loctite is a great safety measure to retain these fasteners.

When using aftermarket polyurethane bushings it isn't as much of a problem. The inner sleeves of those bushings are smooth on the ends and don't dig into the washer. This prevents them from imparting the twisting force into the washer and loosening up the bolts.

Good thing you found the missing bolt while parking the car. As you said, turning your El Camino into a snow plow wouldn't have been pretty. Wash out the threads in the shafts and torque the bolts down with some Loctite, then forget about them. Good luck and be safe.


Tranny Swap
Q: I have started a tranny swap with my '73 shortbed originally equipped with a three-speed floor shifting trans. I dropped that and picked up a five-speed out of an '88 Camaro. I need a crossmember to install this properly and was hoping you could point me in the right direction for not a lot of dough.

Jon Battles
Via email

A: The original factory trans crossmember should be able to slide right back and pick up the T-5 gearbox. You'll need to re-drill the frame to pick up the new bolthole locations. The stamped steel crossmember may need to be trimmed on the front side to clear the transmission case.

If you have issues with your factory crossmember you can pick up a universal trans crossmember (PN 550-40105) from Jegs. This inexpensive crossmember requires fabrication. This crossmember is fabricated out of 56 inches of 11/2-inch, 0.134-inch mild steel that should fit the width of your frame with no problem. It requires you to weld tabs to the factory framerails, trim the crossmember to fit, and weld sleeves into the crossmember for the through bolts for mounting.

If you can, stick with the factory crossmember. You'll find it much easier to modify the factory crossmember to fit than all the fab work required for the aftermarket. Good luck with your five-speed pickup.


Response to "Prindle" in the Nov. '09 issue Q: I've also been around since dirt, and prior to my current position was not familiar with the term "rooster comb." I've been an engineer in the auto trans shifter group of an OEM (not one run by the government) for 14 years. I can't speak for the other OEMs, but the part that creates the detent positions in the auto trans is usually referred to as a rooster comb. This nickname comes from the fact that if you look at the part from the side, it resembles the comb on the head of a rooster. Most drawings refer to this part as the "inner manual lever," but for clarity we normally use rooster comb. It's easier for people to get a visual on what part you're discussing. So Jeff was correct.

And you are correct that the gear position indicators (both next to the floor shifter and in the instrument panel) are called PRNDL.

Phil Guthrie
Farmington Hills, MI

A: Phil, thanks for the response. Guess we haven't been working on the right brand of automobiles all of these years to know what a rooster comb was. Now that you mention it-and describe the visual-we can see the resemblance. Thanks for the education, and good luck back there in Farmington Hills. I understand it's quite tough in the Detroit area.

Long-Distance Chp Family
I read CHP everywhere-at work, in bed, even between traffic lights. You guys are worldwide! I recently bought a '77 Camaro LT right before our government banned importing cars older than five years-it came with 49,000 miles on the clock, a 350, and no performance!

Since my goal was to smoke out LS1s on the street/track, I was left in a car enthusiast dilemma, not knowing what to do with the car. I always bought the best bang-for-the-buck parts so I would like to do it the once-and-for-all way, with a cheap price. Should I rebuild my SBC? Would it only offer limited power? Also, which low-end and top-end kits should I use? Should I build a big-block 454 since gas is cheaper than water over here? Six liters of 95-octane pump gas costs only a dollar. No, we don't ride camels anymore!

Sinan Al-Johary
Riyadh, Saudi Arabia

A: If you're trying to chase LS-powered performance cars, I think you should fight fire with fire. The big-block is a very nice swap, but you add a ton of weight to the front of your Camaro. We'd go with an LS2 swap. You get 6.0 liters of performance for around 450 pounds. This will be a very easy swap for your Camaro. Check with Turn Key to buy a bolt-in engine package with a calibrated controller and harness. This is the easiest way to go about it. If you have access to a crashed Chevy CR8, pull the 6.0L out of that. This is a Holden Commodore-based HSV Clubsport R8 from Australia. GM rebadges these cars as Chevrolets in the Middle East. The CR8 is equipped with a 6.0L LS2 producing 412 hp. This would really wake up your second-generation Camaro.


Q: I'm looking for a new gearbox for my '87 Chevy truck. Currently, I have a stock power gearbox. Is there a manual box with maybe a different gear ratio so it would turn easy but not have the power steering pump to suck power.

James Blue
Semmes, AL

A: Getting something for nothing is pretty tough. Manual steering boxes take a great amount of effort on the driver's part to turn the wheel, especially in a truck. We converted our Malibu wagon race car back to manual steering; the original manual steering box has a ratio of 22:1. This is the only way that you can have enough strength to turn the wheel, and with this high of a ratio you're turning the wheel for days to make a turn. Most power boxes these days are variable ratio and they vary from 12 to 18:1, depending on the vehicle's speed and steering effort.

Of all the accessory drives, the power steering pump probably pulls about 10 hp off the front of the engine at max loads. When the wheel is straight, the pump is bypassing the pressure back to the reservoir; when you're turning the wheels is when most of the load is on the pump.

Is there a way to eliminate the power steering pump and still have power steering? Back in 1990, with its release of the NSX, Honda pioneered the electric power steering (EPS or EPAS). Many small cars, including hybrids these days, are using electric power steering racks. These small racks will draw up to 80 amps of power under full load. These power racks use the stored battery power to assist the driver in turning the wheel. This takes the load off of the front of the engine from the pump and puts it right back on the alternator! Remember, there is no free lunch-the only benefit is that the battery is a storage device and the alternator has time to refill the battery. Building an electric steering box for a full-size truck will take a small powerplant to feed it!

For the time being, we'd stick with your factory power steering pump and Saginaw 800 series P/S box. It's a tried-and-true system that works very well and we'd look for power somewhere else.

Technical questions for Kevin McClelland can be sent to him at



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