Hi all,
I don't know what trucks may have had a 502 v-8. Most of the large Chevys &
GMCs I worked on had 396 and 427 engines. In a large truck you want more
torque to get the load moving.
In the '50s GMC used a 503 straight 6 gas engine, like the smaller 6s it was
bigger on torque than high revving. They were governed at a max of 2800 rpm.
I gotta brag on the old trucks though, my '52 GMC 640 (503) will accelerate
faster than my dept's '75 Chevy C50 (427) with the same load.
As for the 500 Caddy engine, speaking as a mechanic, it is the best designed
of all of GMs V-8s. It is balanced so well it does not have a harmonic
balancer.
It was originally designed to have every accessory on it, so it wasn't a
maze of brackets. You can change the timing chain on one of these engines
without removing any accessory bracket. I could change three water pumps on
a caddy in the time it would take to do one on an Oldsmobile(GM's worst
designed V-8).
It had an external oil pump that could be replaced without pulling the pan.
The front mounted distributor was easy to get to and was cooled by the fan
to prolong the life of the electronics (almost never replaced the module on
a caddy). The fuel pump couldn't wear down the lobe on the cam as it didn't
run off the camshaft, but off a separate drive lobe bolted to the timing
gear.
One of the reasons that the caddy got good milage was the rear end ratio, it
was around 2.50. That big old engine could squall the tires, but at highway
speed was turnin over pretty slow. It really depended on how you drove one,
Little old lady= 20mpg, Easy take offs=14 mpg, Stop light racer=7mpg.
Thats all I can recall right now, I can just say they are a real breeze to
work on.
John
'49 Chevy 3800 Panel (235)
'52 GMC 640 Firetruck (503)
-----Original Message-----
From: SHAWN & JO <yooperwannabe@prodigy.net>
To: oletrucks <oletrucks@autox.team.net>
Date: Thursday, January 13, 2000 8:10 AM
Subject: Re: [oletrucks] 454-502 big blocks
>Caddy used a 500 Big block and nothing will interchange with the 454
>although the Caddy is touted to be the superior of the 2 engines. (Gasp!
>Sacrilege!) The Caddy is supposed to get better gas mileage, cheaper to
>build. Etc, etc. Street Rodder magazine had a year long build up on one in
>98. There are a couple of major players in the Caddy performance industries
>and I can provide names if anyone is interested.
> I'm eventually going to try one in my 81 Chevy Ambulance as it only
gets
>7mpg (gasp, wallet burning a tattoo of itself on my leg as the money
catches
>fire every 10feet down the road.) The Caddy is reputed to get 5-6mpg better
>than the 454 and provide better lowend torque for pulling.
>Shawn
oletrucks is devoted to Chevy and GM trucks built between 1941 and 1959
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