Mopar A – Poly Small Block V8

Intro

The A / Poly small block is not an LA engine wearing antique valve covers.

That matters when the wrench gets near the heads, intake, exhaust, rocker gear, front cover, water pump, and valve covers. The early A-block Poly has its own hardware habits, and a 318 displacement badge does not magically make it a later LA. Use the Poly numbers on Poly hardware or enjoy finding out how expensive “close enough” can get.

General Torque Specs

Bottom End		Top End
Main Cap Bolts	85 lb-ft	Cylinder Head Bolts	85 lb-ft2
Connecting Rod Nuts	45 lb-ft	Rocker Shaft Bolts	17-20 lb-ft3
Oil Pump Mounting Bolt	35 lb-ft	Spark Plugs	30 lb-ft
Oil Pump Cover Bolts	10 lb-ft	Valve Cover Bolts	snug only1
Oil Pan Bolts	15 lb-ft1
Intake and Exhaust		Driveline Side
Intake Manifold Bolts	30 lb-ft2	Flywheel / Flexplate Bolts	55 lb-ft
Exhaust Manifold Bolts	25 lb-ft4	Torque Converter Bolts	25 lb-ft5 65 lb-ft6
Carburetor Mounting Nuts	snug only1	Bellhousing Bolts	50 lb-ft
		Starter Fasteners	18-25 lb-ft
External Engine
Harmonic Damper Bolt	135 lb-ft	Water Pump Bolts	35 lb-ft7
Camshaft Sprocket Bolt	35 lb-ft	Fuel Pump Bolts	30 lb-ft
Camshaft Thrust Plate Bolts	15 lb-ft	Timing Cover Bolts	30-35 lb-ft7
Distributor Hold-Down Bolt	15 lb-ft

¹ Thin covers, pans, carburetor flanges, and cork-style gaskets distort easily. Tighten evenly and do not turn seep control into bent metal.

² Use the correct tightening sequence and bring the fasteners up in stages. A good number used in a dumb pattern is still dumb.

³ Poly rocker-shaft hardware uses a low value. Do not treat it like main-cap hardware.

⁴ Some lower-row exhaust fasteners may enter coolant. Seal the right fasteners instead of pretending dry threads and optimism are the same thing.

⁵ 5/16 in. converter bolts.

⁶ 7/16 in. converter bolts.

⁷ Water-pump and front-cover bolts may enter coolant or oil-path areas depending on layout. Seal the right fasteners.

Aftermarket bolts, studs, rods, intake manifolds, rocker hardware, replacement fasteners, and modified Poly hardware 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 30-35, don’t give one timing-cover bolt 30, the next one 33, 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

• Do not use later small-block intake, rocker, front-cover, water-pump, or valve-cover habits on Poly hardware just because the displacement sounded familiar.
• Poly intake and exhaust parts are their own mess. The canted-valve heads change the top-end layout enough that guessing from later small-block habits is how parts get cracked, warped, or cursed at.
• Rocker-shaft hardware is not a place for gorilla torque. Use the correct Poly value and hardware, not whatever your hand remembers from another Mopar.
• Some exhaust, water-pump, and timing-cover fasteners may need sealant because of coolant or oil-path exposure. If the bolt comes out wet, do not reinstall it like nothing happened.
• Valve covers, oil pans, and carburetor flanges are easy to distort. If the gasket squeezes out, that was not extra sealing. That was you.

Common Mistakes

• Using later small-block Mopar torque habits on a Poly because the displacement matched and thinking stopped there.
• Treating Poly rocker-shaft bolts like heavy structural bolts instead of the smaller hardware they are.
• Forgetting that some Poly exhaust and cooling-system fasteners may need sealer.
• Cranking valve-cover, oil-pan, or carburetor hardware down like the gasket owes you rent.
• Using the wrong converter-bolt value because “converter bolt” sounded specific enough.
• Reading a range and scattering random values across intake bolts, timing-cover bolts, or converter bolts like that was ever a plan.

Bottom Line

The A / Poly small block is real Mopar small-block iron, but it has its own rules.

The trouble shows up at the heads, intake, exhaust, rocker gear, water pump, and front cover.

Use Poly numbers, check the actual hardware, seal the fasteners that need sealing, keep matched fasteners consistent, and don’t let “small-block Mopar” do your thinking.