Thread: Cam advice

Tweet

Flat-top pistons and 64cc heads on a 350 will make ~10.2:1 static compression ratio, too high for pump gas on an iron-headed motor. Use a 12cc dish to make 9.6:1 SCR, such as a Keith Black Hypereutectic #KB193 or other brand hyper piston.

Once you get the SCR under control, match the cam to the SCR and you'll be a happy camper. Here's a suggestion for you if you're planning on using an L31 block or other production roller cam block '87 to '00.....Makes no sense to use a flat tappet block any more when you can find roller blocks for $200 or less.
Crane hydraulic roller grind number HR-276-2S-12 IG, part number 109821
1600-5800 rpm operating range.
Advertised (0.006") duration 276/284
0.050" tappet lift duration 214/222 (hydraulic intensity of 62 degrees for a long, easy life in a street motor)
Valve lift 0.488"/0.509" (L31 heads sign off at just over 1/2" lift at around 5000 rpm's on a 350, so no use in using more cam lift than that)
Lobe separation angle 112 degrees
Camshaft timing events 0-34-48-(6)
Excellent low and mid-range torque and horsepower. Good idle, daily usage, 2600-3400 cruise rpm's.
8.75:1 to 10.75:1 static compression ratio advised.

Can use stock converter, but would work nicer with a looser aftermarket converter and numerically-higher rear gear. Seriously, you can use a 10" 3500 stall converter effectively on the street if you add a front-mounted cooler. Run the trans fluid through the aftermarket cooler first, then through the cooler at the bottom of the radiator, then back to the trans. The aftermarket cooler will often remove too much heat from the fluid, so running it through the bottom of the radiator will add just the right amount of heat to the fluid so it will operate properly in the transmission. Do not mount any aftermarket back under the car. You will cook the transmission. Mount it out front in the air stream.

With a static compression ratio of 9.6:1, this cam, installed straight up, will produce a dynamic compression ratio of 8.5:1, perfect for pump gas in a street motor. I would guesstimate 400 hp and 425 ft/lbs of torque if you use an Edelbrock RPM #7116 intake, 750 carb and 1 5/8" long-tube, tuned headers with an H or X pipe after the collectors and before the mufflers. Run the pipes out to the back of the car to prevent under-car exhaust from resonating against the under-car sheet metal and making you crazy. Also, let the motor breathe by using a 14" x 4" tall air filter assembly. I advise against using the Air Gap intake manifold if you live anywhere it gets cold. Use the conventional #7116. If using a manual transmission or 3000+ torque converter with an automatic, use a double-pumper carb. Under 3000 torque converter, use a vacuum-secondaries carb.

Use 20 degrees initial ignition timing at the crank, with another 14 degrees in the weights, all in by 2800 rpm's. If the starter motor kicks back against the increased timing, interrupt the power line to the coil and insert a momentary-off push button on the dash. Hold the button down, wind the starter up and release the button and key switch. Presto, the motor will be running with no starter drag. Crane makes a nice, adjustable vacuum cannister so you can dial in some fuel mileage when you get the break-in completed.
Here's the limiter plate to use.....
http://www.summitracing.com/parts/crn-99619-1/overview/
and here's the can.....
http://www.summitracing.com/parts/cr...FaY1QgodhzIAkA

Use these springs and retainers. No cutting. Good for mild hydraulic roller cam like I spec'ed above.
http://www.alexsparts.com/valve-spri...rf-hyd-roller/

Pin the rocker studs with this kit....
http://www.summitracing.com/parts/mrg-806g/overview/

Use the stock 1.5:1 ratio rail rockers. Check closely for clearance between the rocker rail and the top of the retainer. If the rocker pushes down on the retainer instead of the tip of the valve, you won't like what happens next.

Use this tutorial for finding exact top dead center so you can time the motor with a light.....correctly.
http://www.crankshaftcoalition.com/w...op_dead_center

Use this tutorial for adjusting the valves before initial start-up......
http://www.crankshaftcoalition.com/w...stment_SBC/BBC

.