Editing Choosing an engine for a GM A/G-body

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==Introduction==
The GM A and G-body cars are some of the most liked and sought after cars of the muscle car era and beyond. Engine swaps are common; many of these cars came with inline 6, V6, or small V8 engines. While these engines can be OK performers, many times a larger or modified V8 engine is used to replace the original powerplant.

==Body codes==
===A-body===
*1964-1977 Chevy Chevelle
*1964-1981 Chevy El Camino
*1970-1981 Chevy Monte Carlo
*1964-1970 Pontiac Tempest, GTO
*1964-1981 Pontiac LeMans
*1964-1972 Buick Special
*1964-1972 Buick Skylark, GS
*1964-1973 Oldsmobile Cutlass, 442

===G-Body===
*1978-1988 Chevy Monte Carlo
*1978-1983 Chevy Malibu
*1978-1987 Chevy El Camino
*1978-1987 Buick Regal, Grand National
*1978-1988 Oldsmobile Cutlass, 442
*1978-1987 Pontiac Grand Prix
*1978-1981 Pontiac LeMans/Grand LeMans
*1982-1986 Pontiac Bonneville 

{{Note1}}The metric G-body was actually classified as an A-body from its inception in 1978 all the way through the 1981 model year. During the 1982 model year, RWD A-bodies (including the A-special coupes e.g. Monte Carlo, Cutlass Supreme) were renamed the G-body (which was first used in 1969 with the Pontiac Grand Prix) when the A body designation was used with its midsize front wheel drive automobiles (Celebrity, Cutlass Ciera, Century, 6000). These cars are sometimes listed as A-bodies as a result, but are actually G-bodies.

==Popularity of the GM A-body==
As seen below, fully 12 of the top 13 top selling muscle cars were GM A-cars! No wonder they're still popular today.

[[File:Muscle car ranking.jpg|350px]] <br style="clear:both"/>  

==What engine to swap into the A/G-body?==
There are very few GM engines produced during the muscle car era that won't fit the A or G-car platform. Cadillac used a different motor mount set up, but even it could be used if the motor mounts were fabricated or bought from the aftermarket. All the V8s from the other makes (Buick, Olds, Pontiac, and Chevrolet) will exchange among the different makes. This opens up a LOT of combinations of body-to-engine swaps that can be done.

That said, there are many hobbyists (both casual and purists) who feel that the car make should match the engine. A lot of this opinion is brought about by the perception that every car nowadays seems to have a [http://www.crankshaftcoalition.com/wiki/Why_not_to_use_a_small-block_Chevy_engine Chevy engine] under the hood. And while Chevy engines are fine performers, to many they lack that certain "something" when installed in a make other than Chevrolet.
   
===Pontiac GTO as an example===
Take the 1967 Pontiac GTO as an example. Even though any of the GM V8s will fit, there are those who would say even using a 389 would not be correct, because 1966 was the last year of the 389. The motor that was originally installed in the 1967 GTO would have been a Pontiac 400. Pontiac V8s from 1955-'64 would also fit- and would also be incorrect to a purist. 

In cases where the original engine has been lost to time is where the tough decisions have to be made: Do I install a "correct" engine (same as what would have been installed from the factory), or is using ANY Pontiac V8 'good enough', or is using a non Pontiac engine altogether OK? Some die hard performance enthusiasts would say to use the biggest, baddest engine that will fit between the fenders- regardless of the make, and purists be darned. Others of course will fall somewhere in between.

But these days (ca. 2012), unfortunately, budget considerations often take priority over the desire to have a numbers-matching and/or correct restoration. And there are those who are not into the whole numbers matching deal and could care less who thinks what; it's their car, they're paying the freight, and they feel the right to build their car the way they want not what someone else thinks is "right".

If a GTO does not have the original engine, any later Pontiac (301-455) would bolt in. The 455 has gobs of torque and there are many aftermarket parts now available, including stroker kits. While some of the iron round port Pontiac heads are good performers, their cost is out of sight when compared to an aluminum aftermarket head that can outflow them while costing and weighing much less. The horsepower and streetability of the large Pontiac engines is impressive. They bolt right in, however driver side headers may need slight modifications. Some of the A-body cars are on the heavy side (G-bodies not so bad), so a larger engine is a big asset. A strong transmission like the TH400 is a very good choice if an automatic is to be used. 

==Resources==
*[http://www.maliburacing.com/bbc_conversion.htm Big block Chevy in a G-body]
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[[Category:GM]]
[[Category:Engine]]
[[Category:General hotrodding]]