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Techin' In with Fletch - May 2008

By Dan Fletcher

Intake Care

I have '68 Camaro with a ZZ4 crate motor. I am currently replacing thecam, and the aluminum intake is a bit rough looking. Is there anything Ican do to make it look new again? Also, I heard from an engine builderthat when I put the intake back on I should get rid of the front andrear intake gaskets and use silicone instead. I have the GM intakegaskets for it, but what is your take on this? I would appreciate yourinput, as the car is heading to the body shop in the next couple ofweeks.

Kevin Feiock
Via e-mail

ANSWER

The aluminum intake will clean up easily. You just need to have it glassbeaded. Most any machine shop will have the equipment required to do so,and it should cost next to nothing. Your intake should look brand newwhen you're done. As for the front and rear intake gaskets, I agree withthe engine builder. Simply put a nice healthy bead of RTV across theblock surfaces, making sure to give it a little extra blob in thecorners. Let it tack up for a minute or two, and then carefully set theintake down. Obviously, you don't want to be shifting it around a lotafter having made contact with the silicone.

Nova 400 Plan

I'm building a motor for my '73 Nova. This car will be used on thestreet, and on weekends it will be used on an eighth-mile dragstrip. Theshort-block has been assembled. Now it's time to choose the cam andheads. To keep costs down, I'm trying to use parts leftover from otherprojects. I'm sure this won't be a high-rpm engine, and I would like touse a hydraulic flat-tappet cam and pump gas.

The short-block is a 400, bored .030 over, with a 3.75 cast crank, SpeedPro H615CP pistons and 5.7 Eagle rods clearanced for up to .600-inchlift cam. The assembly is externally balanced, and the pistons sit.025-inch below the deck at top dead center. I have an EdelbrockPerformer RPM Air-Gap intake and Holley 750 HP carb with vacuumsecondaries. I also have the Performer RPM camshaft, but I'm not sure ifit's a good fit. I have Edelbrock Performer RPM cylinder heads with 64ccchambers and straight plugs. Also on the shelf are Dart Pro 1 215ccintake runners and 64cc angle plug heads.

The other parts being used in this car are a Turbo 350 trans, B&MHoleshot 3000 converter (PN 20413), Hooker headers (PN 2451), and a 21/2-inch exhaust with Flowmaster mufflers. The rear end is a 12-boltwith 4.10 gears and slapper bars. The slicks are 29 inches tall, and thestreet tires are 28 inches tall.

What cam and heads will work best for what I'm trying to do? I wouldconsider selling one set of my heads and buying something else if I haveto, but it would be nice if I could use what I already have. Likeeveryone else, I expect 500 horsepower, 500 lb-ft of torque, 20 miles tothe gallon, and 10-second timeslips. With your recommendations and onpump gas, what kind of power and performance do you think I can expect?What will my compression ratio be? Do you see any major problem with myplan, and is this a good way to go? My torque wrench is waiting for youranswer.

Dave McVicker
Lagro, Indiana

ANSWER

You're right, the 400 isn't going to be a high-rpm piece, but that'sOK--it will do plenty of work down low. By the sounds of it, yourleftover parts seem to pretty much duplicate Edelbrock's Power PackageTop End Kit, PN 2098. For a street/strip application such as yours, Ithink this sort of recipe is a great plan. You could put more cam in it,but bigger isn't always better. They've already done the homework foryou, so let's just run with it...use the Edelbrock cam and cylinderheads you have in stock.

According to the Speed Pro book, that number piston with a 64cc cylinderhead is going to yield a 10.3 compression ratio. Obviously, you're goingto have to run "premium," and even with that you may have to spruce itup just a tad. The gear, converter, carburetor, and header size you'vechosen all seem about right, though in a perfect world I would probablywant the converter to be just a touch looser.

You don't mention what the car weighs, but if we take a shot at about3,300 pounds with the driver, I would think it's got to run very deepinto the 12s, maybe even slipping into the 11-second zone. This wouldequate to approximately a 7.70 e.t. at your local eighth-mile facility.In my opinion, you have a well thought out combination that shouldperform admirably both on and off the track.

Getting Cagey

I have a '69 Camaro that I want to put a rollcage in. There are only acouple of problems with that: I would like to use the back seat to putfour people in there and actually be able to get them out of the rear ofthe car without having to cut the rollcage. I'm looking for a very rigidcage because I'm putting a 454ci engine in the car.

Nolan Smith
Barrie, Ontario

ANSWER

I'm down with the backseat idea...that's what I did with my '69 Camarostocker. I had the seat, thought it was ballast in the right place, andliked the look of it. I never really anticipated carrying passengers,but it did turn out to be a handy addition when the whole family wentcruising at the Hot Summer Nights event in Reno a couple of years back.

I don't believe anyone specifically designs anything to fit around a '69Camaro back seat and promote ease of rider installation and removal.You're most likely going to have to adapt a store-bought kit to yourneeds or have something custom made. Here's a link to a kit sold byJEG's: www.jegs.com/webapp/wcs/stores/servlet/product_10001_10002_55662_-1

If it were me, I would put in a swing-out side bar and leave out theseat bar that runs sideways across the car, behind the front seats.Here's a link to the swing-out side bar kit:www.jegs.com/webapp/wcs/stores/servlet/product_10001_10002_751122_-1_10775

If you ever wanted or needed to make the cage pass NHRA or IHRA chassiscertification requirements, you could always just add the seat bar. Andif the firewall is unaltered, a dash bar is not required (neither of mycars has one).

Unless you cheat the rollbar forward, there's going to be some minorinterference with the seat at the floor. And I really don't think youshould bias the bar forward, because then it's going to start to move itinto the door opening. Due to time constraints at the moment, I justjammed mine in place, bending the seat frame. That worked for me, but alittle time, effort, and upholstery help should put you in better shape.The bars that run from the rollbar to the trunk go through the rearshelf, so there's no concern there.

Blew A Gasket

I own a '97 Camaro Z28 in which I recently blew the head gaskets. Ifixed the head gaskets and shaved the heads, and the car ran fine forabout two days, but then I had to start filling the radiator withantifreeze every time I started it. Also, every time I punched the gasit would overheat very quickly. When I opened the hood I would hear asizzling sound coming from the motor's left side. Now when I add coolantit pours off the left side of the block as quickly as I put it in. Whatcould it be? Is it the freeze plugs on that side, because I can't seeexactly where it's coming from? Any help would be great.

Richard Nadeau
West Jordan, Utah

ANSWER

Sorry to be the bearer of bad news, but it's probably not a freeze plug.I mean, it could be, but that would be quite a coincidence, wouldn't it?If you're really lucky, it's somehow coming from the crossovertube...maybe it's loose, cracked, etc. But the crossover tube is at theback of the motor, not the side, where you're describing the leak to beseen (and heard). Most likely, you either have more head gasket issuesor a cracked cylinder head. Ultimately, I'm thinking the heads are goingto be back off the car again. Before just throwing another set of headgaskets at the problem, take the heads to a reputable machine shop tohave them pressure checked. And, as always, torque the heads tomanufacturer specs when reinstalling.

Super Chev ... er ... GMC

Last year I bought a '72 GMC Sprint truck/car (it's virtually a Chevy ElCamino). This is a vehicle I've wanted to own for many years, and I waslucky to find a very original, largely rust-free example that I willprobably keep for some time and plan to drive often. It has the base 350engine/automatic with 114,000 original miles. The engine runs solid andI won't be doing anything internally. However, the intake manifold andcarb were, at some point, replaced with much later model parts. Themanifold has several extra fittings that are blocked with bolts. Thecarb just can't quite be adjusted right. It either runs perfect at idleand not as smooth at speed, or too strong at idle and perfect at speed.I suspect it's missing some "environmental" accessories found on later-model 350s.

I'd like to install an aftermarket manifold and four-barrel carb and getit running smoothly with a little more power. Given it is a base-model350, I would like to select a manifold/carb combination that is a proper fit to get a little more out of the engine but not overdo it. I reallyjust want to keep this truck/car running well and reliably.

Lou Johnson
Bucyrus, Kansas

ANSWER

I would recommend a tried and true pairing of the Edelbrock Performerintake manifold (PN 2101) and carburetor (PN 1406), which is a 600-cfm, square-flange, electric choke (non-EGR) unit. This is an extremelyuser-friendly, bolt-it-on-and-go combination.

Shaky Situation

I have a '70 Chevy Nova. When I get the car up to around 60 mph, the cardevelops a slightly rough ride, but if speeds are under 55, the ride isas smooth as glass. This problem has been with the car over the years.The steering column will start to shake a little, and you'd think rightoff that the tires need to be balanced. I have had the tires balancedand rechecked. I have had the front-end checked and no problems on playwere found. I had the alignment done this summer after I replaced allthe A-frame bushings and ball joints using a PST polygraphiteperformance front end kit in case the rubber was starting to dry rot orwas cracking on the bushings. Inner and outer tie rods had no play, so Ididn't replace them. I had new tires installed and the problem is stillthere.

I'm running new gas shocks on the front with factory (YJ) code 14x7wheels all the way around with radial 245 tires on the rear and 205tires on the front. The car came factory with drum brakes, and I updatedthe front brakes to power disc brakes system using '72 Chevelle (used)spindles and hubs back in the early 1980s. The front wheel bearings areproperly adjusted. Could the front hubs be out of balance, or maybe thedriveshaft is out of balance?

James
Fort Smith, Arkansas

ANSWER

It sounds as though you've done all the right things in your attempt todiagnose the problem. Ninety percent of the time, the answer to thisproblem is a tire out of balance or a bad tire, but you've pretty mucheliminated those possibilities. For that matter, you've pretty mucheliminated the front end, which is certainly what I would've done, too.

So, in no particular order, here are a few thoughts on where to focusyour efforts. No, I don't think it's the spindles or hubs. It could be afront or rear U-joint, or the driveshaft is out of balance, but I would think you'd feel that in your butt, not in the steering wheel. But that doesn't cost much to look at, and at this point, we just want it fixed,so take the driveshaft to a specialist and have the U-joints replacedand the shaft balanced. Right or wrong, let's check that one off thelist.

It could be a bent wheel, but I would think the person balancing thetires would have noticed a shimmy, assuming they were done on a spinbalancer. It could be the bushing in the back of the transmission. Is itthe original driveshaft? If not, it could be that the front yolk is notengaged far into the trans. It could be motor-related. Is the motorsmooth at high rpm? Is it the original motor and trans? If not, it couldhave the wrong flexplate or harmonic balancer. If it does have thefactory harmonic balancer, the outer ring could have shifted on the huband thrown the motor out of balance. Stop me if I get warm ...

If nothing I've suggested helps, humor me ... when no one is looking,rotate the tires, mismatched sizes and all, just to see if anythingchanges.

By Dan Fletcher
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