January 2013 Chevy High Performance Q&A

Kevin McClelland Jan 28, 2013 0 Comment(s)

L92/Wagon Marriage

As I mentioned last month, I thought I would get some quality time with our wagon and the L92 small-block destined to fit between its framerails. Well, since we last spoke, I’ve put all my time into getting the engine together and ordering the last components necessary to drop the engine in. If you recall, I said that we had spec’d out a COMP hydraulic roller that was just small enough to fit without intake valve reliefs in the pistons. That was my first challenge. Probably, if I’d have gone with production LS3 hollow-stem intake valves over the Manley racing hollow stems, we might have made it. The production valves you could shave with the margins, and the Manleys have a good, safe margin of approximately 0.060 inch. The production valves have a nasty habit of dropping the head of the valve when pushed into racing applications. Better safe than sorry. When I degreed the cam and checked the valve drop, the valves were hitting the pistons by 0.038 inch. We reached for the Isky catalog and purchased the pilot and a 2.250-inch cutter to cut the small valve pockets in the pistons as needed. It was a little bigger exercise than I expected, but that’s done now.

1301chp 01 O January 2013 Chevy High Performance QA Kevin McClelland 2/3

I was going to go with the complete Muscle Rods engine swap with Hedman Hustler headers, which make the installation a snap. Well, after installing the Milodon racing oil pan, which has a widened sump for added oil capacity, and the pan dropped away from the rotating assembly to reduce windage, I decided to make my own mounts. Also, with making my own mounts I may cut the main crossmember to lower the engine and get a better driveline angle. I did order the Hedman headers and they just came in this week. Hedman puts together a beautiful set of 13/4x17/8-inch step headers that I went with. My plan is to make killer torque and shift at 7,000 rpm and gear the car to go through the lights at 7,000 rpm. These headers should give me both great torque and outstanding power to the upper-rpm range.

My concern with lowering the engine is that the car currently launches off of a 3,000-rpm chip and will pull the front wheels around 10 inches to a foot. Adding around 100 lb-ft of torque on the launch and taking at least 100 pounds off the front of the car (50 pounds for the engine and a fiberglass cowl hood) I’m worried that the front end is going to go skyward. Not that I don’t like a good wheelie every once and a while, but what’s the name of the game? Win lights!

Finally, with the way projects go around the McClelland household, you buy parts when there is money in the bank, so this project has been moving along in $300 to $500 chunks. Some parts, I purchased well over a year and a half ago and put on the shelf until needed. Today I opened something I purchased at least a year ago, and one of the components was machined incorrectly, and the part is scrap! Mind you, I work for a large performance aftermarket company, and it is a challenge supplying quality components to our customers every day. My take on this is that we should all inspect our parts as soon as we get them, making sure it’s what we ordered and that it’s perfect. It will prevent delays like mine. I guess it will be another weekend until the engine is complete. Until next month, wrench safely.

Resto Stuff

Where can I find parts for my ’67 Chevy Chevelle 300 deluxe two-door post. I’m looking for a window to trunk panel, inner front fenders, all glass window felts … I need lots of parts. Please help.

1301chp 02 O January 2013 Chevy High Performance QA 67 Chevy Chevelle 3/3

John Vieira
Manteca, CA

Rear window to trunk panels loved to rust out in the second-gen A-bodies. Check with Goodmark for all your sheetmetal needs. The window to trunk panel you’re looking for is called the Deck Filler Panel, PN 4031-710-66. This fits all hardtop ’66-67 Chevelles. For new front inner fenders, check out PN 4031-350-67L and R. These are exact replicas of the factory pieces. Goodmark also offers many of the trim and window seal pieces for your Chevelle.

For the glass felt, window seals, door seals, and rubber parts, check out companies like Classic Industries, National Parts Depot, and YearOne. We’ve been very pleased with all of the parts we’ve used from these companies, and they all have great customer service. Check them out online and see who works out best for you.

Enjoy restoring your ’67. You couldn’t have picked a better time to start your restoration. Almost everything has been reproduced to bring your Chevelle up to better-than-new standards. Good luck with your project—hope your checkbook holds up!

Sources: classicindustries.com, goodmarkindustries.com, yearone.com, npdlink.com

Steer in the Right Direction

I’m the proud owner of ’64 Nova SS, white with red interior. I can’t find the original red steering wheel anywhere. Can someone please point me in the right direction?

Rick Barber
Brooklyn, NY

What Chevy II owner wouldn’t be proud? We dug around all the reproduction houses and no one we could find offers original reproduction wheels for anything earlier than ’67 models. A quick search on eBay Motors yielded a perfect-condition ’64 Nova wheel with the horn trim ring and everything. The money wasn’t that bad at $150, either. The only issue is that the wheel was white. The restoration houses offer special paint to refinish steering wheels, and the base color white is easy to refinish.

Also, you should network with your Nova brethren. There are many Nova clubs around the nation, but check out the National Nostalgic Nova Club. They have free classifieds to their members, newsletters, and events around the country.

Unfortunately, used and refinished may be your only option. We have to remember that our early Chevys aren’t getting any younger. Yours is right at the half-century mark. Take care of her and enjoy!

Source: ebay.com, nnnova.com

502 for the Masses

We have a 502hp/502-cid GM crate motor with an 850 Holley. It runs with 10-10.5 inches of vacuum at 800-850 rpm idle. Is that enough vacuum for power brakes? At higher rpm, 1,500 and up, the vacuum runs about 14-15 inches but does not go up when you quickly let off the throttle. Our power brake booster is in the trunk, plumbed with a hard line. The engine only has an hour of run time on it (in the shop, not highway). It also runs rich. We have not done an air/fuel mixture test yet, but it is definitely rich. Any suggestions on jet sizes? I enjoy your magazine, and it has a great Q&A section. Thank you!

Ed Jacobson
Port Angeles, WA

A Chevy 502 crate engine is one of the best choices for great performing street machines. They are not too radical to drive power accessories and power brakes. Yes, the 10-10.5 inches of idle vacuum is right at the low side for power brakes. You mentioned the idle speed, but didn’t give an idle spark advance spec. We would shoot for 16-18 degrees of initial spark advance at idle, and 32-34 degrees at 3,200 rpm. Then add vacuum advance on top of that. This will give you the best idle quality and vacuum you’ll see out of this package. As for the rich idle, we assume this carburetor is the GM-tuned 850 supplied with the Deluxe engine package. If it is, it’s already jetted properly and all you need to do is set the correct float level, then adjust the idle fuel screws to the lean best idle. Remember, with the overlap of the 224/234-duration camshaft at 0.050-inch tappet lift, you’ll have unburned hydrocarbons at idle, even when the carburetor is adjusted properly.

If your engine is equipped with a standard list number 4781 850-cfm Holley double-pumper, the factory jetting should be very close. These carburetors have four-corner idle, course-threaded feed screws. Very slight adjustments change the fuel flow significantly. Again, first adjust the float levels to their appropriate levels, then adjust the idle fuel screws to your lean best idle. With this type of carburetor, you want all four idle feed screws to be adjusted to the same point. This will take some finesse, as you should start with all of them about one turn out from fully closed. Then choose one screw and turn it in (leaner) until the idle speed begins to drop. Once you find where it’s sensitive, say, a half turn out from seated, go back to one turn out and close all the screws, say, an eighth of a turn. Then return to the screw you started with and lean it again. Now it only goes another eighth to a quarter turn before the idle begins to drop. Repeat the procedure and slowly equalize the four screws to your lean best idle. You know it’s right when you can just tap the accelerator pump arm and squirt in a slight amount of fuel and the idle won’t climb. If the engine speed goes up with a slight squirt of fuel, the idle fuel adjustment is too lean. Repeat your idle fuel adjustments until the accelerator test causes no change in engine speed.

Enjoy the ton of torque these engines have on tap. Down the road, when you’re tired of the power, you have a great foundation to kick it up a notch. These short-blocks will handle just about anything you want to throw at them. We’ve enjoyed many a dragstrip lap behind a 502 short.

Source: holley.com

Geared Up!

I have just swapped a brand-new 357-cid small-block into my ’83 4x4 truck, and am now wondering about gearing. The engine has 10:1 compression ratio and 230/236 degrees duration at 0.050-inch lift, with a max lift of 0.490 inch. The engine is in front of a 700-R4 transmission, and I have 33-inch tires. The truck will be driven on the street, but driveability is of no issue to me. What torque converter and rearend gears would be desirable? Thanks for the great magazine.

Thomas Quinn
Via email

Getting almost 21/2 tons of fun moving can really put a load on a small-block Chevy. When you install taller-than-stock tires, you just kill the gear multiplication—that’s the only thing your little engine had going for it. The 700-R4 First gear of 3.06:1 gave it some low-end grunt. Let’s take a look at the gearing choices that won’t make your truck fun to drive yet unusable.

Luckily, with the 700-R4 you can get pretty silly with the rearend gearing yet still have a very streetable truck. The 0.7 overdrive and the lockup converter really gives you a nice driver. Your truck probably came with 3.73:1 rear gears from the factory. The original tires on your truck were 29 inches tall. With these tires and gearing, your truck is loafing down the freeway at 2,000 rpm at 65 mph. By throwing your 33-inch tires on the truck, the 65-mph engine speed drops down to just above 1,700 rpm.

Now, let’s have some fun. By dropping your gear ratio down to 4.88:1, you still retain a 65-mph cruising rpm of 2,250, which is a great range for your mild cam 350. Also, with the very low 3.06 First gear in the 700-R4 and the combination of the 4.88 rear gears and 33-inch tires, the truck will still pull 40 mph in First at a redline of 6,100 rpm. It would really wake up the acceleration of your rig.

As for the converter, a mild 2,400 stall would give you one hell of a launch with the combination of low gearing. Check with Monster Transmission for its Punisher Pro Street lockup converter. The 2,300-2,500 lockup converter (PN HD7730) features furnace-brazed impeller fins. Also, we wouldn’t recommend going away from the lockup feature. With the weight of your pickup, even with the low rearend gears, you would be right at the edge of your stall speed at freeway cruising speeds. This will cook the trans fluid and eventually the transmission. Check with Monster at 800.708.0087 for more information.

We hope this all makes sense. Let us know how the truck launches after these mods. Also, watch it when you put this puppy in four-wheel Low. With the gear multiplication of your transfer case, your driveshafts may want to leave the truck!

Source: racetransmissions.com




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