What is a 396 "Rat" Motor - Impala Tech
Performance Our High Performance Area

LinkBack Thread Tools
post #1 of 9 (permalink) Old 08-19-2010, 01:09 PM Thread Starter
Join Date: Jan 2010
Location: California
Posts: 90
What is a 396 "Rat" Motor

I have heard a few people use the term "Rat" when describing certain 396 motors. Can anyone explain what defines a motor as a 396 Rat?

I know what the 396 is but I'n not familiar with the "Rat" designation.

Headrage is offline  
Sponsored Links
post #2 of 9 (permalink) Old 08-19-2010, 01:45 PM
Lifetime Premium Member
Join Date: Mar 2009
Location: Lake Worth, FL
Posts: 374

This might help.

Ape Out.

Make: Chevrolet
Model: Impala Custom
Year: 1969
Doors: 2
Engine: 327 V8
Trans: Powerglide
Ape is offline  
post #3 of 9 (permalink) Old 08-19-2010, 02:37 PM Thread Starter
Join Date: Jan 2010
Location: California
Posts: 90
Interesting read. I did a little digging and it looks like for the most part the "Rat" just denotes a big block.
Headrage is offline  
post #4 of 9 (permalink) Old 08-19-2010, 02:46 PM
Join Date: Jul 2009
Location: Canada
Posts: 1,506
Yep, Rat is Chevy big block, and mouse is small block. Interestingly, some of the "mouse" motors displaced more than the "rat" motors...

Two doors, four doors, wagons, and ragtops.
jayoldschool is offline  
post #5 of 9 (permalink) Old 08-19-2010, 03:38 PM
Senior Member
Join Date: Jun 2008
Location: Near Chicago
Posts: 703
I think Bill "Grumpy" Jenkins may have started the 'mouse' name with his potent small block Chevy's in NHRA racing when he put the hurt on Mopar's "elephant" hemi's. From there the Mark IV big block Chevy came out and followed suit with 'rat motor'. According to an article on Gasser Madness, a guy named Skip Hess is given credit for coining the term "rat motor" when the first AHRA racers started dropping blown big blocks in Anglia gassers in 1965. It was painted on the Shores and Hess Anglia scoop first:


Scroll down to the 1964-1967 period. Cool stuff.
1968 Caprice 396 is offline  
post #6 of 9 (permalink) Old 08-19-2010, 05:05 PM
Senior Member
Join Date: Apr 2010
Location: Monroe NC
Posts: 1,094
......................it's allways a good day when you see a Impala catch a "Rat".....................
68imp is offline  
post #7 of 9 (permalink) Old 08-20-2010, 09:31 AM
Join Date: Jan 2006
Posts: 13,022
Small block Chevy V-8 was refered to being a mouse because of it's power to weight ratio starting about 1956-'57. The only engine with a better ratio is the 455 Buick engine which is about 30 pounds heavier than a SBC but about the same size (it wasn't introduced untill 1970). It was the previously unheard of lightness of the engine that caused everyyone to drop the other 1957 power champ; the 364 cid "Nail Head" Buick motor, and and the older 1947 vintage 331 cid Caddy motor that weighed a ton compared the SBC that was out putting the same amount of power out of a lighter package. In racing every 100 pounds is one tenth of a second off your elapsed time so a smaller more pottent power plant became very popular very quickly.

The "Rat" was the "Mouse's" distant cousin which could be made to deliver lots of power but was never considered light weight, and to this day still can not match the horsepower per cubic inch of the diminutive mouse motor.

I have been breeding and feeding Rat motors since they were introduced. Always looking to give a Rat a good home.

Big Dave
Big Dave is offline  
post #8 of 9 (permalink) Old 08-24-2010, 10:56 AM
Senior Member
Join Date: Sep 2008
Location: Sparta, Missouri
Posts: 175
I try to give as many "Rat's" a good home as possible. All my hotrods have heavy hearts.

Don't listen to me, what do I know? I've only been doing this for 30 years.
earthquake68 is offline  
post #9 of 9 (permalink) Old 08-24-2010, 05:51 PM
Senior Member
Join Date: May 2009
Location: nj
Posts: 122
great pictures-they were great times
bf63imp is offline  
Sponsored Links

Quick Reply

Register Now

In order to be able to post messages on the Impala Tech forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

User Name:
Please enter a password for your user account. Note that passwords are case-sensitive.


Confirm Password:
Email Address
Please enter a valid email address for yourself.

Email Address:


Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page

Posting Rules  
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On

For the best viewing experience please update your browser to Google Chrome