Need some advice 318 POLY vs 318 LA
As far as "larger footprint", I assume he means the physical size- the poly is just shy of 25" across the valve covers, while the LA is right about 20". So the LA is narrower, which makes sense since the LA was initially developed to more easily fit within the confines of the A body engine compartment and reduce the manufacturing costs associated with the poly heads.
Weight is also a factor, Hughes published this list of weights:
It gives an approximate difference of 75# between the LA and poly. The majority of that weight difference is in the heads, although a fair amount is in the block itself, with the LA being produced with newer "thinwall" casting methods to further reduce weight. Remember, "LA" is "Light A".
As far as "larger footprint", I assume he means the physical size- the poly is just shy of 25" across the valve covers, while the LA is right about 20". So the LA is narrower, which makes sense since the LA was initially developed to more easily fit within the confines of the A body engine compartment and reduce the manufacturing costs associated with the poly heads.
Weight is also a factor, Hughes published this list of weights:
It gives an approximate difference of 75# between the LA and poly. The majority of that weight difference is in the heads, although a fair amount is in the block itself, with the LA being produced with newer "thinwall" casting methods to further reduce weight. Remember, "LA" is "Light A".