Posted By: pittsburghracer
Hemi question. How many gen's are there - 03/11/15 05:28 PM
The post on Dart blocks got me to thinking. I see gen 1,2, and 3 listed all the time on Moparts. Not being a Hemi guy exactly how many gen's are there and what are the differences.
Posted By: 340B5
Re: Hemi question. How many gen's are there - 03/11/15 06:02 PM
Unless I missed something;
Gen1=Desoto,etc
Gen2=Superbee, Cudas etc
Gen3= Modern Challengers, Ram trucks etc
Posted By: hudsonhornet7x
Re: Hemi question. How many gen's are there - 03/11/15 08:03 PM
I have heard of some of the newer engines being mentioned as a Gen 4. Is this the 6.4, 6.2?
Posted By: Oyvind Mopar
Re: Hemi question. How many gen's are there - 03/11/15 08:47 PM
In addition Mopar made the race stuff branded "Hemi" (P5 Hemi and Hemi 99) that are not counted into the generations....
Posted By: polyspheric
Re: Hemi question. How many gen's are there - 03/11/15 10:18 PM
They can also be loosely grouped based on their block dimensions:
G1 includes the oldest Chrysler, DeSoto and Dodge hemis with rear-mount distributor. Although very similar in design they all have different deck heights and bore pitch. This series does not include any LA-based or Plymouth-branded engine.
G2 is based on the RB platform with front-mount distributor.
G3 is a mod on the LA/Magnum engine.
More data on my page here:
http://victorylibrary.com/mopar/m-table.htm
Posted By: chryco
Re: Hemi question. How many gen's are there - 03/12/15 12:46 AM
3
Gen 1 - Dizzy in back 51 - 59
Gen 2 - Dizzy in front 63 - 71
Gen 3 - Coil packs no Dizzy present
Posted By: polyspheric
Re: Hemi question. How many gen's are there - 03/12/15 11:28 PM
You'll see references to bore center distance, bore pitch, cylinder to cylinder on-center distance etc.
This is the major factor that separates engines into families (not deck height) because it governs which head, cam, and crank fits what, and suggests what cross-brand conversion may be possible (such as SBC V8 head on Chevy L6).
Chrysler has used quite a few (* some now extinct). Here they are, in size order:
4.090" Jeep & Dodge truck 4.7 liter OHC
4.1875" Dodge Red Ram hemi & poly (also Plymouth & DeSoto poly)*
4.3125" DeSoto Firedome hemi*
4.460" A, LA, Magnum, Gen-3 hemi
4.5625" Chrysler Firepower hemi & poly*
4.800" B, RB, Gen-3 hemi
(gen 1 5.7- 6.1 and Gen 2 2009 and up Eagle engines and then there is the Apachie too..) 
That's where I was really getting confused. You would think there would be a much better way to address the newer engines than to go back to past engine naming. 
