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Re:a little A and LA engine stuff

From: jeffc
Remote Name:
Date: August 04, 2003


Lars, I will fill in any voids left out, LA engines were introduced in the 64 model year as a light weight V8 engine that would fit "A" body cars and A100 vans in the form of the 273ci size. The 273 had wedge type heads, but shared most bottem end parts with the earlier "A" engines (i.e.A318 poly). The 273 is, like the poly, a solid lifter engine (used the same lifters), the later 318, 340 and 360 have hydro lifters and the poly A318 engine also had a hydro lifter engine used in heavy trucks (class 2 and 3 engines depending on years *poly engines have oil passages that will handle hydro lifters without mods, just lash the valve to 0 (hydro cam grind needed) ). The block is about 80lbs lighter than the A engine casting, this was made possable by the wedge head and a lighter block casting (most of the saving is in the heads). The LA 318 was introduced in 67 models in the US market replacing all poly A318 engines, although the A318 poly was still used till 67 in many Canada made trucks and some cars. Putting the 2 blocks side by side, A and LA, you will see that the casting differances that would not be noted otherwise, they look darn close and have the same profile, but the poly has heaver webing cast into the upper block. To install the poly heads on the LA block you need the poly cam (yes, it fits in the LA and the cam bearings are the same), channel a place for the oil return into the deck of the LA block (hole is lower in the LA block), grind clearance for the push rods in the block (casting in LA block, were the head meets the block is a little higher and the intake push rods need a little more space). There are also water passage holes that are differant in size, but they line up and the size differance does not seem to mater. Oil passages are also the same. Depending on pistons used in the LA block you may need poly pistons because of the valve cut in the piston top for the canted intake valve. Bolt up the heads, add the poly intake and ex mans and your on your way........... just for those that may want to know


Last changed: May 04, 2010