What pushrod length do I need?

12 Remove the pushrod-checking tool and count how many turns out the tip is. For each full turn out, 0.050-inch length should be added to baseline measurement of the checking tool. In our case, two turns out generated the proper clearance, meaning the pushrod length needed for our engine is about 6.800 inches.

How long are stock BBC pushrods?

The big block Chevy will need two different checking pushrods—the intake version accommodates lengths from 7.80 to 8.80 inches.

How do I know if my push rods are too short?

If the witness mark is too close to the intake side of the valve-stem tip, the pushrod is too short. If the witness mark is in the middle or toward the exhaust side of the valve-stem tip, then the pushrod is too long.

Which pushrod is longer intake or exhaust?

Consequently, Exhaust pushrods on G.M. 3.1 and 3.4 engines are longer than their intake counterparts. As a result, It’s critical to reinstall, the correct length pushrods in the correct place.

How long are big block Chevy pushrods?

The adjustable pushrods come in five separate lengths from 5.800 to 10.800-inch. Each pushrod will offer one inch of travel. For example, the 10.800-inch version pushrod tool will extend out to 11.800 inches.

Does push rod length matter?

Truth be told, pushrod length is critical even with an adjustable valvetrain, but even more so on the non-adjustable LS. Know that improper length, meaning too long or too short, can cause anything from a drop in power to catastrophic failure of one or more major components.

What happens if my pushrods are too long?

If the pushrod is too short, the mark will be toward the intake (inboard) side of the valve tip. If the pushrod is too long, the travel will be toward the outboard or exhaust side of the valve tip. An ideal pushrod length will minimize the travel across the center of the valve tip.

What replaced pushrods?

Pushrod vs Modular Though overhead valve (OHV) engines have largely been replaced by overhead cam engines (OHC), there are still dedicated pushrod proponents out there, and certainly, both styles have their pros and cons.

Why can’t pushrod engines rev high?

Most pushrod designs feature two valves per cylinder. Without extra valves, the engine can’t take in enough air at higher rpm and it becomes starved for air. Thus, it can’t rev as high. The number of camshafts and valve timing are the final reasons pushrod engines don’t rev very high.

What should the pushrod length be on a BBC roller?

So as long as your heads are stock, the valves are the stock length and your using a stock ratio rocker, you can just subtract whatever was milled off the heads and block deck from the lengths of the recommended pushrods and that will give you the length that you will need. Granted head gasket thickness can adjust for this.

How big of an AFR Head do I Need?

AFR heads are available bare (without parts), call our tech line for details. Please see footnotes for additional information. Important: Do not use your AFR gasket as a template to port match your intake manifold as one AFR gasket is used for many AFR runner volumes. Note: Angle mills might require a .120″ Thick intake gasket.

Can a cylinder head be removed from a pushrod?

AFR strongly recommends material be removed from the piston and not the cylinder head. Our combustion chamber shapes are very critical to flow and altering the cylinder head can adversely affect flow and power production. It is the customers responsibility to verify proper piston to head clearance. Heads are designed for 3/8″ pushrods.

How big is a 265cc BBC oval port cylinder head?

AFR’s 265cc “As Cast” heads are the cost effective performance choice over re-worked factory heads. They feature partially CNC ported intake, exhaust & chambers, A356 aluminum castings and high quality components throughout. Recommended for street, towing, or street/strip engines with displacements up to 468 cubic inches, operating up to 6200 RPM.