Chevy Small Block Evolution - Performance Q&A

Kevin McClelland Feb 1, 2010 0 Comment(s)

A: We're pretty sure about this one. If you check the body tag under the hood, the first line of numbers after "ST" will give you the model year then the body code. The Laguna Type S3 was only built in a two-door sport coupe in '76. Its body code is 1AE37. The El Camino was built under two body codes: the two-door pickup delivery (1AC80) and the two-door classic pickup delivery (1AD80). GM built the Laguna series from 1973 to 1976. As for a Laguna El Camino, we can't find one from any of those model years. A 350ci with a four-speed manual, that is rather rare.

Check out the body codes. If it's one of those listed above, then there's no question about it. It's a standard El Cam with a Laguna nose attached. Good luck.

Flaming Malibu
Q: I have a Carter street pump feeding an Edelbrock single fuel pressure regulator. The dual feeds from the regulator are feeding a Holley 80457S 600-cfm carb. This 600 has dual-feed bowls from a Holley 3310S 750-cfm carb that has been running without a problem since 2006. The fuel pressure gauge started showing 0 with the engine running fine. There was no stalling or flooding, but a very inconsistent flat spot or hesitation was noticed. After replacing the Carter pump and regulator, and ensuring the Russell bronze fuel filter was clear, the engine starts now with 6.5 psi but idles down to 0 psi. The necessary float level setting with the engine warm has created a serious flooding problem the last two days on cold initial starting. The first day I backed off the float setting to get the car out of the garage for fear of a fire. When I started the engine cold I noticed that the fuel pressure was 6.5-7.0 psi and the floats stuck, flooding the engine.

This same flooding happened to me once before with the single-feed bowls that came stock on the 600-cfm carb. After tapping the bowl the overflowing gas stopped. This flooding scares me, to think if it occurs when engine is hot. I'm being told that Holleys are notorious for this sticking needle and seat problem. The car is street driven. I suspected vaporlock, but again the setup had run perfect since 2006. I'm in serious need of help. Rufus Martin Via email

A: The last thing you need is flames in your Malibu. We'd be suspect of your fuel pressure gauge. We've got an inexpensive "mail order" pressure gauge screwed directly into the Magnafuel regulator on our Malibu wagon. When the engine is cool, the gauge reads somewhat accurately. When the engine warms up the pressure drops about 2 to 3 psi. When we screw in a quality Snap-On test gauge, the pressure is rock solid at both cold and hot operation. Your problem sounds the same. You set the pressure when the engine is cold and the pressure drops when hot. Then you adjust the pressure hot and the engine is running. When you start the car cold the fuel pressure gets a run at the needle and seats and they can't control the pressure and flood over.

Also, Holleys can maintain very accurate fuel bowl settings without the sticking of needle and seats if the pressure is correct. The "center hung" bowls that you've upgraded your carb with have very little trouble. You may be hearing old wives' tales about the Holley needle and seat troubles. Stick with the Holley brand needle and seats sized for the carburetor that you're running. Installing performance, larger needle and seats are no way to go on the street. If you have carb-kit needle and seats, replace them with original Holley units, PN 6-504. These needle and seats are 0.110 inch with a Viton tip needle and are used in all center-hung float assemblies for the 4150 model carbs. Check the Holley website for the proper technical info on adjusting the floats properly.

Again, we think your fuel pressure gauge is going to be the culprit. You've changed the regulator, which would be our next best thought. Hopefully a simple adjustment of the floats and fuel pressure setting will mellow out your fireball. Be safe.

Source: holley.com

Make It Stop
Q: My '95 Chevy S-10 two-wheel-drive truck came with a four-cylinder and a five-speed transmission. Since then I have installed a 350ci small-block with tall valve covers and no room for a power brake booster. I can hardly get it to stop now. I've used several different standard brake master cylinders with the correct brake rod, but no luck. When you apply the brakes, the pedal feels like a booster failure in a power brake system. I have disc brakes in the front with drum brakes in the rear.

The engine is a 0.040-over 350 with flat-top, four-valve-relief hypereutectic pistons with about 10.2:1 compression. I'm using World Products Sportsman 2 with 64cc chambers and 2.02/1.60-inch intake/exhaust valves, an Edelbrock Victor Jr. intake, and a 750-cfm Holley. The heads and intake have been ported and polished. Also, an MSD billet distributor and 6AL box and Blaster 2 coil. The valvetrain consists of all Comp Cams items: stud girdles, Pro Magnum roller rockers, Magnum pushrods, solid lifters, and an Xtreme Energy XS 282 S cam. The transmission is a B&M 350 turbo with a B&M Holeshot 3,600-stall converter. The headers are Hedman full-length 15/8 with a 21/2-inch Flowmaster dual-exhaust system and have 4.10:1 gears.

This truck is mostly used for street. How or what can I use to stop the truck? We have tried everything. Also, any idea about how much horsepower I might have? Stanley Wilcher Via email

A: When you removed your power booster unit and replaced the system with a manual brake master cylinder, did you use the same master cylinder pushrod location on the pedal? Most people do. The reason you have very little brakes is that you don't have any pedal ratio (leverage) over the manual master. With power brakes you need much less pedal effort to create a ton of pressure-the booster does all the work for you. A normal power brake pedal ratio is in the 4:1 range. When you run manual brakes you must increase the pedal ratio to gain leverage over the master. You'll find manual brake pedal ratios somewhere in the 6:1 to 7:1 range. Take a look at your brake pedal. Usually The General uses the same pedal for both manual and power applications. There will be two locations for the pedal pushrod to mount. The only difference will be the location of the master cylinder. You will need to remount the master to put it inline with the new pushrod location.

If you don't have two locations on your pedal for the pushrod, it's very easy to figure out the proper location. First, you need to know the total length of the pedal from the pivot point to the center of the brake pedal pad. Divide this length by the length of the pushrod location to the pivot point. This will give you the pedal ratio. Move the pushrod location to bring you into the above listed ratios.

As for the ponies from your little small-block, we'd peg it around 430-440 hp, with around 420 lb-ft of torque. This should be pushing around your little S-10, and we can see why you need some brakes. Be safe and get this puppy stopped!

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

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