<VV> Prefered motor for 65 Monza 4speed? (John Gull)

Dale Dewald d66dewald at gmail.com
Sun Oct 15 14:30:55 EDT 2017

On 10/12/2017 12:00, John Gull wrote:

>> Now to consider a standard140 or a PG140  with Standard shift bell housing for my 4 speed car! I have both motors and they both will need rebuilding before using in my 4 speed Monza. Which would you all prefer to use and why one over the other? Thanks in advance for your reccomendations John in NC pondering this age old question!
Hello John,
I think the decision on which motor to rebuild [which really boils down 
to what cam to install] depends on how you will be using your car and 
what differential ratio and transmission you have [or want to  build].

Please first determine what differential you have.  If the car was 
originally optioned with a 140 engine then it most likely will have a 
3.55:1 R&P ratio.  If it had a 110, then it will likely have a 3.27:1 
ratio.  These often get changed during the 50+ year life of the car so 
it is necessary to count teeth or measure turns to find out what is in 
there.  If you plan to also rebuild the differential and/or the 
transmission then there is the option to install a 3.08:1 [OTTO parts] 
R&P gear.

For s street car with a 3.55:1 differential you will want to rebuild the 
standard 140 with the factory 891 or 304 cam or Isky 270, OTTO OT-20, or 
similar mild performance cam.  There might be some newer cams to 
consider.  In this case you will want to use the the stock '65 
transmission [3.20:1 first gear].

For a street car with the 3.27:1 differential and stock '65 transmission 
there is more to consider.  You might want to build in a little more low 
end torque with the 140 engine by using one of the mild performance cams 
(OT-20, 270, etc) with a modest 2 degree advance.  This can be done with 
an offset key on the cam gear.  Talk to your engine builder about this, 
especially if he can do some computer modeling.

If you build a 3.08:1 differential to make a highway cruising car then 
you will also want to build a custom '65 4-speed using the gearset from 
the 64-65 FC with a 3.65:1 first gear.  Then you will want to build a 
140PG type engine using a low performance engine cam; GM 889, OT-10, 
Isky 260, etc (consider also a special torque cam sold by Ken Hand) 
installed in the engine with a 4 degree retard.  Your 140PG engine will 
have the correct retarded gear already installed on the crankshaft.  Use 
this crank with the cam of your choice.

FWIW, my wife's '65 Monza has a '65 FC transmission and 3.08:1 
differential installed behind a rebuilt +0.060 over 110 engine. This is 
a very nice combination for a road car. The added torque from the bored 
engine makes this combination work.  Some improvements to the stock 
heads would likely yield even greater performance with the comfortable 
cruising RPM's of the 3.08.  I have yet to go on a really long trip with 
this car to find out what MPG it is able to get.

For more specific information you may email me directly.

Dale Dewald
Hancock, MI

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