I don't get it, about the Chevy 454 and Buick 401s Oldsmobile 455s are they that different? Did the manufactures built there own engines? Especially since they say to me Chevy 454s are not good out of the rest of the other engines from different manufactures.
I hear crazy stuff about Cadillac 500s and 472s getting better fuel mileage than 454s despite larger size :\
Yes,all 4 of GM's divisions built their own engines up to a certain point..after about 1978 GM had some divisions go on strike and they started "sharing" engines among the 4 divisions..
After 1978 you could see Pontiacs and Buicks,Oldsmobiles with 305 Chevy engines,or they may have had a V6 Buick in them,or one of their own engines ...since all 4 divisions shared basically the same chassis platforms it was fairly simple to swap in one of the other engines..the frames had the motor mount holes already drilled,all you needed was the right motor mount brackets and mounts..
As an example,a Pontiac Firebird could have come with a Buick V6,Chevy V8,a Pontiac 400 or 455,or an Olds 403,depending on what you ordered,or what GM had available to stuff in them that day..
Oldsmobile had a 455 up until 1976 or so,which was completely different than a Buick 455,and Pontiac had their own 455 also,up to around the same year..no interchangeable parts among any of those 3 engines despite having the same cubic inch displacement....opinions vary as to which ones were the "best",in my opinion they all had their quirks and faults,just like any other engine of any brand..
I think the Chevy 454 is better myself due to the fact more hop up parts are available cheaper,and they are as durable as any of the other 3..now Olds,Buick and Pontiac engines are getting scarce and expensive..454's aren't exactly plentiful any more either,especially older carbed ones..
I cant recall ever selling many engine parts like rings,bearings,etc,for Olds and Buick engines,I guess either no one rebuilt one when they wore out or they just junked the cars,or bought a good running used engine instead..or they never needed rebuilding !.
.Pontiacs always had top end issues ,timing chains & gears and lifters were a common item to be replaced on them..but their engines were decent otherwise..they had a sturdy bottom end..many race engines are (or were) based on Pontiac blocks..
Caddy 472 & 500 V8's did get somewhat better mpg than other big blocks but mostly due to their great low end torque ,and the fact they usually put a 3:08 or even higher geared diff behind it and most Caddy drivers were old farts who chugged along at low speeds and never opened the secondaries on the Q-jet...
A friend used to own a '68 Olds Delmont 88 that had a 455 with a factory 2 bbl carb,3:08's and it had 10.75 to 1 compression--that car could smoulder the tires endlessly,yet if you drove it gently,you could squeak 15 mpg out of it..its the lower compression after 1971 that killed off the engines efficiency and power more than anything else.
I know of a few old Vettes with the 375 HP version 327,that could cruise at 70 mph all day and deliver over 15 mpg,because they had 11:1 compression back then..most engines today have 9:1 or less..
And we don't have high octane leaded gas to run them on any more either,so its not a good idea to build a high compression engine now,unless you like buying race fuel for $25 for 5 gallons..
