Looked at Some Motors Today

Poly block refers to first gen "A" motor's, Poly meaning Polyspherical head design. Allpar lists the small blocks as manufactured between 64 to 67. 2nd generations "LA" small blocks were manufactured from 67 to 90. 273,318,340 and 360's motors are "LA" engines. These 2nd gen LA motors were very common as they were put in eveything from trucks and A Bodies to the bigger Cop cars. Contrary to popular belief, not all Big cars had big blocks.

I believe the Magnum small blocks were manufactured from 1991 on up and became the engine of choice for todays younger crowd.

I've always believed that if you took an "LA" motor and a GM 350 and built them similarly, meaning that dollar for dollar and pound for pound the build was as equal as possible, the LA mill would smoke the GM mill...and my GM friends tend to agree.

Go to http://[URL="http://www.allpar.com/mopar/poly"]www.allpar.com/mopar/poly.html[/URL] for a more comprehensive discription.