Has anyone built a 350 oldsmobile approx 300-350hp?

Engine tech, for those engines, products, and technologies of yesteryear.

Moderator: Team

falcongeorge
Expert
Expert
Posts: 952
Joined: Mon Jul 27, 2009 2:17 pm
Location: Surrey, BC

Post by falcongeorge »

Didn't some 403 blocks have windowed main webs ?
ClassicComp
Expert
Expert
Posts: 932
Joined: Mon Jan 23, 2006 10:50 pm
Location:

Post by ClassicComp »

all have windowed mains from what i have heard.
results speak for themselves
falcongeorge
Expert
Expert
Posts: 952
Joined: Mon Jul 27, 2009 2:17 pm
Location: Surrey, BC

Post by falcongeorge »

I know not all of them do, cause a buddy had one down that didnt ( saw it torn down), but I think a LOT of them do, i would avoid those like the plague, even at the 350 hp level.
Dodge Freak
Guru
Guru
Posts: 1711
Joined: Sun Oct 21, 2007 6:56 pm
Location:

Post by Dodge Freak »

Its been 20 years since I was in to them--then got hook on Mopars.

Its fuzzy but I believe I recall the 1976-1977 blocks were the ones to get.

Fuzzy too is something about the Olds diesel engines being taken way over bore and running on gasoline.

There should be a few good forums on Olds cars-442's etc. Over there some would likely know.
falcongeorge
Expert
Expert
Posts: 952
Joined: Mon Jul 27, 2009 2:17 pm
Location: Surrey, BC

Post by falcongeorge »

Yea. thats what I seem to recall, the first two years of production had solid main webs, the later ones didnt. Man, thats some scary sh*t even in a production lo-po smogger!
rocketracer380
Pro
Pro
Posts: 331
Joined: Fri Jun 20, 2014 8:41 am
Location:

Re: Has anyone built a 350 oldsmobile approx 300-350hp?

Post by rocketracer380 »

for a decent low budjet build a 350 .068 over 3.5 stroker 330 crank offset ground with 2" sbc journal 6" sbc rods 374 cubes should yield about 400 + hp with stock olds #7' s with 2" int 1.625 ex valves
Schurkey
HotPass
HotPass
Posts: 1858
Joined: Sun Mar 01, 2009 2:42 am
Location: The Seasonally Frozen Wastelands

Re:

Post by Schurkey »

falcongeorge wrote: Mon Jul 27, 2009 9:17 pm I know not all of them do, cause a buddy had one down that didnt ( saw it torn down)
The Olds forums I'm on would DEARLY love to see photos of a solid-main-web 403.

They've been looking for one for decades and never seen one.
Geoff2
Guru
Guru
Posts: 1980
Joined: Mon Nov 09, 2015 4:36 pm
Location: Australia

Re: Has anyone built a 350 oldsmobile approx 300-350hp?

Post by Geoff2 »

There must be something about 11 year old threads!
rocketracer380
Pro
Pro
Posts: 331
Joined: Fri Jun 20, 2014 8:41 am
Location:

Re: Has anyone built a 350 oldsmobile approx 300-350hp?

Post by rocketracer380 »

low buck olds build sbc enginetech .060 flattops 1.54 cd std bore and deck 350 olds block std 3.385 stroke cut to sbc journal and widened or narrow rods ls 6.098 long either bush rods to .927 or machine pistons for ls pins must cut for spiro locks you end up appr 0 deck and 10:1 comp depending on cc no need for valve relief with under .600" lift if the bore is straight just a light hone is required this combo should net 375/400 with # 7 heads and rpm intake
Jeff Lee
Pro
Pro
Posts: 444
Joined: Sun Jun 26, 2011 1:20 am
Location: Anthem / Phoenix Arizona

Re: Has anyone built a 350 oldsmobile approx 300-350hp?

Post by Jeff Lee »

I’m no Olds guy but geez....they made a 350 W-31 in 1970 that was 325HP from the factory. With modern finishes, rings, cams, and stuff, 350HP sounds like childs play to me. Being the tread is 11 years old, maybe we can get an update.
NHRA SS/G
1970 AMC AMX - 390 4-speed
Advanced Clutches - Red Line Racing Cams
falcongeorge
Expert
Expert
Posts: 952
Joined: Mon Jul 27, 2009 2:17 pm
Location: Surrey, BC

Re: Re:

Post by falcongeorge »

Schurkey wrote: Tue Oct 13, 2020 12:25 am
falcongeorge wrote: Mon Jul 27, 2009 9:17 pm I know not all of them do, cause a buddy had one down that didnt ( saw it torn down)
The Olds forums I'm on would DEARLY love to see photos of a solid-main-web 403.

They've been looking for one for decades and never seen one.
Wish I knew where it was now, it would look great beside the "imaginary" steel large journal 3.25 crank I pulled out of a 307. The forum "experts" claim that doesn't exist either. :lol:
Post Reply