Ford  Big Inline-6

Intro

The 240 / 300 big six is tough enough to make people stupid.

That is the trap. These engines earned their reputation by surviving abuse, but that does not make them a small Ford six, a small-block V8, or a universal truck-engine torque chart. Use the big-six numbers and match the actual hardware.

General Torque Specs

¹ Ford 240 head bolts.

² Ford 300 / 4.9L head bolts; staged procedure, with later engines needing year-specific confirmation.

Aftermarket bolts, studs, rocker gear, manifolds, and replacement head bolts use the part maker’s number and lube instructions. Don’t use this chart to overrule the parts in your hand.

A range is not a game of horseshoes. If a matched set shows 60-70, don’t give one bolt 60, the next one 66, and the last one whatever your elbow liked. Pick one value in the range and use it consistently across the set unless the real procedure says certain bolts get different numbers.

Notes

• The 240 / 300 big six is not the 144 / 170 / 200 / 250 small Ford six. Do not drag small-six numbers onto big-six hardware.
• The 300 head-bolt job is a staged procedure, not permission to scatter random values across the head.
• The 240 and 300 share plenty, but the 300’s longer stroke and long production life mean mixed-year parts are common.
• The long intake and exhaust manifold setup needs the right pattern. Treat it like a short V8 manifold and it’ll leak just to spite you.

Common Mistakes

• Using small Ford six torque values on a 240 / 300 because both engines are straight sixes.
• Treating every 300 / 4.9L head-bolt job like every year used the same final procedure.
• Overtightening valve covers and oil pans until the gasket has no chance.
• Ignoring the intake and exhaust manifold pattern on a long inline-six manifold setup, then blaming the gasket.
• Reading a range and scattering random values across head bolts, mains, rods, or manifold bolts like that was ever a plan.

Bottom Line

The 240 / 300 Ford big six is durable, simple, and not a small six.

That reputation for toughness is not permission to guess.

Match the actual big six, respect the 240 / 300 head-bolt split where it matters, keep matched fasteners consistent, and don’t let “straight six” do your thinking.