60's 425 vs. 455 Olds engines
Thread Starter
Registered User
Joined: Mar 2010
Posts: 1,322
From: Nova Scotia, Canada
60's 425 vs. 455 Olds engines
Good day all,
Just a little nerdy discussion for us noobs who are just learning. I always wondered why the 68' Toronado 455 engine somehow had less power than the 66' Toronado 425? The engines seem to share a bunch of components and you'd think that the 455 would be a more powerful engine considering it's a bit bigger. Just wondering if anyone knows if there is there more to this story?
I often wondered if the 455 was actually more powerful but got de-rated due to insurance or something along those lines. I know quite a few engines of that era were significantly de-rated for one reason or another.
Just a little nerdy discussion for us noobs who are just learning. I always wondered why the 68' Toronado 455 engine somehow had less power than the 66' Toronado 425? The engines seem to share a bunch of components and you'd think that the 455 would be a more powerful engine considering it's a bit bigger. Just wondering if anyone knows if there is there more to this story?
I often wondered if the 455 was actually more powerful but got de-rated due to insurance or something along those lines. I know quite a few engines of that era were significantly de-rated for one reason or another.
Old(s) Fart
Joined: Mar 2007
Posts: 50,815
From: Northern VA
The top Toro 425 was rated at 385 HP/480 ft-lbs. The top Toro 455 was rated at 400 HP/500 ft-lbs. What was your question again?
FYI, in both cases peak HP was at 4800 RPM and peak torque was at 3200 RPM. Of course, one should take these numbers with a grain of salt, since no one can assume that Olds put the development effort into the 1970 W30 motor with unique heads, intake, carb, distributor, and 328/328 cam just to make 30 HP LESS than was already available with that Toro motor.
FYI, in both cases peak HP was at 4800 RPM and peak torque was at 3200 RPM. Of course, one should take these numbers with a grain of salt, since no one can assume that Olds put the development effort into the 1970 W30 motor with unique heads, intake, carb, distributor, and 328/328 cam just to make 30 HP LESS than was already available with that Toro motor.
Thread Starter
Registered User
Joined: Mar 2010
Posts: 1,322
From: Nova Scotia, Canada
The top Toro 425 was rated at 385 HP/480 ft-lbs. The top Toro 455 was rated at 400 HP/500 ft-lbs. What was your question again?
FYI, in both cases peak HP was at 4800 RPM and peak torque was at 3200 RPM. Of course, one should take these numbers with a grain of salt, since no one can assume that Olds put the development effort into the 1970 W30 motor with unique heads, intake, carb, distributor, and 328/328 cam just to make 30 HP LESS than was already available with that Toro motor.
FYI, in both cases peak HP was at 4800 RPM and peak torque was at 3200 RPM. Of course, one should take these numbers with a grain of salt, since no one can assume that Olds put the development effort into the 1970 W30 motor with unique heads, intake, carb, distributor, and 328/328 cam just to make 30 HP LESS than was already available with that Toro motor.
I must have my info wrong obviously.
Thread Starter
Registered User
Joined: Mar 2010
Posts: 1,322
From: Nova Scotia, Canada
Ohhh ok, I see......there was an optional pkg available on the Toronado 455 that bumped it up to 400HP. The standard Toronado 455 had 375HP.....that's where I got it mixed up.
So as there was no other engine available in 66-67 on the Toro, the standard later 455 was down 10 HP from the 425 in typical form. I wonder why the reduction in HP?
So as there was no other engine available in 66-67 on the Toro, the standard later 455 was down 10 HP from the 425 in typical form. I wonder why the reduction in HP?
Last edited by ourkid2000; Jun 21, 2023 at 02:07 PM.
Thread Starter
Registered User
Joined: Mar 2010
Posts: 1,322
From: Nova Scotia, Canada
The top Toro 425 was rated at 385 HP/480 ft-lbs. The top Toro 455 was rated at 400 HP/500 ft-lbs. What was your question again?
FYI, in both cases peak HP was at 4800 RPM and peak torque was at 3200 RPM. Of course, one should take these numbers with a grain of salt, since no one can assume that Olds put the development effort into the 1970 W30 motor with unique heads, intake, carb, distributor, and 328/328 cam just to make 30 HP LESS than was already available with that Toro motor.
FYI, in both cases peak HP was at 4800 RPM and peak torque was at 3200 RPM. Of course, one should take these numbers with a grain of salt, since no one can assume that Olds put the development effort into the 1970 W30 motor with unique heads, intake, carb, distributor, and 328/328 cam just to make 30 HP LESS than was already available with that Toro motor.
Old(s) Fart
Joined: Mar 2007
Posts: 50,815
From: Northern VA
Ohhh ok, I see......there was an optional pkg available on the 455 that bumped it up to 400HP. The standard 455 had 375HP.....that's where I got it mixed up.
So as there was no other engine available in 66-67 on the Toro, the standard later 455 was down 10 HP from the 425 in typical form. I wonder why the reduction in HP?
So as there was no other engine available in 66-67 on the Toro, the standard later 455 was down 10 HP from the 425 in typical form. I wonder why the reduction in HP?
The 1966-67 425 in 385 HP form used cam P/N 390961 with 281/282 deg duration and 55 deg overlap
The 1968-70 455 in 375 HP form used cam P/N 400117 with 258/272 deg duration and 44 deg overlap
The 400 HP W34 motor used cam P/N 400165 with 287/287 deg duration and 57 deg overlap. Note that 400165 was also used in the 1969 H/O, the W33 Delta, and all 1970 442s with automatic (including AT W30 motors).
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