The 403 Olds has siamese cylinders and similar architecture to the 400
Chev. It also has a high nickel content block casting that resists the out
of round cylinders the Chev was famous for. I see lots of 403's in
motorhome use with well over 125 thousand miles on them. That speaks well
for them.
I have heard comments about swapping cylinder heads on 400 Chevy for
hi pro ones, only to have the bottom end fail. Easier to find a 4 bolt main
350 than to mess with the 400.
That's what I did with a K5 full sized Blazer. Originally a Diesel,
then swapped for a 400 small block, finally built a fairly good 350 4 volt
for it that lasted 15 years or so before the tin worms attacked the non
rust proof Fisher body. Those blazers and suburbans were wretched examples
of poor quality control and no rust proofing.
Jim Hupy
Salem, Or
78 GMC ROYALE 403
On Fri, Jun 8, 2018, 8:04 AM John R. Lebetski
wrote:
> The 400 SBC was just a confusing head scratcher. Way lighter than a 403 BB
> Chevy but a 400 BigBlock Buick was only like 25 with plenty of meat
> in the block. Kind of makes sense they combined divisions into GM
> Powertrain.
> --
> John Lebetski
> Woodstock, IL
> 77 Eleganza II
>
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
>
http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>
