Ford  Model A & B

Intro

The Model A / B four is not a Model T with a better hat.

These engines are still old Ford iron, but the A / B hardware, head, flywheel, manifolds, and rebuild habits deserve their own page. Treat them like Model T parts or later Ford parts and the engine will find the expensive part of your assumption.

General Torque Specs

Bottom End		Top End
Main Bearing Cap Nuts	70-80 lb-ft1	Head Nuts	55 lb-ft2 65 lb-ft3
Connecting Rod Nuts	45 lb-ft	Spark Plugs	25 lb-ft
Oil Pump / Oiling Hardware	10-15 lb-ft	Valve Cover / Side Cover Hardware	snug only5
Manifolds and Carburetor		Driveline Side
Intake / Exhaust Manifold Nuts	45 lb-ft	Flywheel Bolts	55-65 lb-ft4
Carburetor Mounting Hardware	snug only5	Pressure Plate Bolts	20-25 lb-ft
		Flywheel Housing to Block Bolts	55 lb-ft
External Engine
Crank Pulley / Ratchet Nut	80 lb-ft	Water Inlet / Outlet Hardware	35-40 lb-ft
Camshaft Nut	100 lb-ft	Timing Cover Bolts	25 lb-ft
Oil Pan Bolts	snug only5

¹ Common Model A / B main-bearing value; babbitt fit and rebuilder guidance still matter.

² Standard Model A / B head-nut value.

³ Common high-compression head value where the head maker calls for it.

⁴ Common Model A / B flywheel-bolt range; match the actual fasteners and safety-wire setup.

⁵ Thin covers, small screws, carburetor flanges, and cork-style gaskets distort easily. Snug evenly; do not reef on them.

Aftermarket rods, rebuilt babbitt work, high-compression heads, replacement studs, reproduction fasteners, and modified Model B hardware use the rebuilder or part maker’s number. 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 55-65, don’t give one nut 55, the next one 61, 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 fasteners get different numbers.

Notes

• Model A / B does not mean Model T. Do not drag T-era numbers forward onto A / B hardware.
• Head nuts are commonly torqued in stages to 55 lb-ft on standard heads. High-compression heads may call for more. Follow the head maker, not bar-stool folklore.
• Main-bearing references vary because babbitt work, bearing fit, and rebuild practice matter. The wrench does not replace the fit.
• Flywheel and flywheel-housing hardware need the right fasteners and safety wire where the original setup calls for it.
• Thin covers, pans, and carburetor flanges are easy to bend. If the gasket squeezes out, that was not extra sealing. That was you.

Common Mistakes

• Using Model T torque values on a Model A / B because all early Ford fours looked old enough.
• Using one head-nut number on aftermarket or high-compression heads that came with their own instructions.
• Trusting torque alone on babbitt bearings instead of checking fit, shims, and rebuilder guidance.
• Cranking thin covers, pans, and carburetor hardware until the old parts bend.
• Reading a range and scattering random values across head nuts, mains, rods, or manifold nuts like that was ever a plan.

Bottom Line

The Model A / B four is tougher and newer than the Model T, but it is still old Ford iron.

That means torque matters, but fit, fastener condition, gasket crush, and rebuild practice matter too.

Match the actual A / B hardware, respect the head and bearing details, keep matched fasteners consistent, and don’t let “early Ford” do your thinking.