403 compared to 455

[ffkjr]

Hi All,
Newbee here in the Northeast. I’ve been researching and shopping for one of the beloved coaches and find this list very informative, thank you!

My question today is, do I need to be concerned with the coaches equipped with the 403 engines, as compared to the original earlier 455? Generally more cubic inches equals less stress and an easier life for the engine. I appreciate any thoughts and apologize if this topic has been discussed previously.

Thanks for your time all!

Frank Kehr

 

[peer oliver schmidt]

> do I need to be concerned with the coaches equipped with the 403 engines, as compared to the original earlier 455
no.

--
Best regards

Peer Oliver Schmidt
PGP KeyID: 0x4196BF22
'76a 26' Eleganza II - Virginia, US
'73 23' Sequoia - Schleswig-Holstein, Germany

 

[Rdenney]

Lots of folks get very good service from 403’s, even with heavy late
coaches. It affects some parts you might buy, but that’s all. And usually
those latest coaches have the latest features and enhancements.

Condition of the coach is vastly more important. I’d take a solid
403-powered coach over a less-solid 455-powered coach any day, and vice
versa.

Rick “not concerned at all” Denney

> Hi All,
> Newbee here in the Northeast. I’ve been researching and shopping for one
> of the beloved coaches and find this list very informative, thank you!
>
> My question today is, do I need to be concerned with the coaches equipped
> with the 403 engines, as compared to the original earlier 455? Generally
> more cubic inches equals less stress and an easier life for the engine. I
> appreciate any thoughts and apologize if this topic has been discussed
> previously.
>
> Thanks for your time all!
>
> Frank Kehr
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>
--
Rick Denney
73 x-Glacier 230 "Jaws"
Off-list email to rick at rickdenney dot com

 

[hal stclair]

I've had both a 403 and a 455 motors in a 1977 Royale and prefer the 403. The 403 will benefit more with a gear change as the torque isn't quite as
much as the 455 but will run with it's big brother when permitted to spin. The 403's do get better mileage, on the order of 1-2 mpg's which is a big
deal for some. As stated, the advantages of the later coach upgrades makes the 403 units preferable for many.
Hal
--
1977 Royale 101348,

1977 Royale 101586, Diesel powered,

1975 Eleganza II, 101230,

1974 Eagle Bus 45',w/slideout,

Rio Rancho, NM

 

[jerry work]

Hi Frank, Welcome and enjoy your new adventure wagon. Proper gear=
ing is far more important than engine size. If you drive in any kind of hi=
lls you want something close to 3.7 final drive ratio. Stock is 3.07 and i=
s way too tall for the weight and bulk of our coaches, but was all GM had a=
t the time. That was the trailer towing option for the Toro. Properly gea=
red, both engines will perform well. The 403 is happy turning a little fas=
ter. Both are robust cast iron monsters more than up to the task. Carbure=
ted trying to function using todays gasoline formulations is a bit of a cha=
llenge. An up grade to self learning EFI and electric fuel pumps will pay =
major dividends in terms of driving like a modern vehicle with little impac=
t on fuel economy. You will most likely average 8-10 no matter what you do=
. If you want better economy, slow down. Every 5mph you slow down on aver=
age will yield around 1 more mpg. If you drive mostly in the flat you can =
likely get by EFI systems offering lean cruise and greater spark advance to=
get around 1 to maybe 2 mpg more in flat land driving, but at the risk of =
higher internal temps and potential pre-ignition once you start to climb ev=
en a little bit. A well placed knock sensor is a big help, but neither eng=
ine was ever designed with a knock sensor from the factory so we are wingin=
g it a bit to find placement for one now. Many owners have done so and man=
y of us made the decision not to take that risk. Jerry Jerry Work =
The Dovetail Joint Fine furniture designed and hand crafted in the 1907 f=
ormer Masonic Temple building in historic Kerby, OR glwork =
http://jerrywork.com =E2=80=94=E2=80=94=E2=80=94=E2=80=94=E2=80=94=
=E2=80=94=E2=80=94=E2=80=94=E2=80=94 Message: 2 Date: Fri, 16 Nov 20=
18 09:38:57 -0500 From: Frank Kehr To: gmclist=
st.gmcnet.org Subject: [GMCnet] 403 compared to 455 Message-ID: Content-Type: text/plain;=
=09charset utf-8 Hi All, Newbee here in the Northeast. I?ve been =
researching and shopping for one of the beloved coaches and find this list =
very informative, thank you! My question today is, do I need to be con=
cerned with the coaches equipped with the 403 engines, as compared to the o=
riginal earlier 455? Generally more cubic inches equals less stress and an =
easier life for the engine. I appreciate any thoughts and apologize if thi=
s topic has been discussed previously. Thanks for your time all! =
Frank Kehr -----------------------