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73-87 Chevy _ GMC Trucks => Engine/Drivetrain => Topic started by: shpark2 on March 10, 2007, 01:59:00 pm

Title: '72 455 Olds Rocket IN, 350 OUT
Post by: shpark2 on March 10, 2007, 01:59:00 pm

1980 GMC C15 Heavy Half

I been lookin' and measurin', the best I can eyeball is that the 350 is roughly 23-24" from outer edges of the exhaust manifolds.  This is of course right between the frame rails, it only looks like the manifolds have MAYBE 1" clearance to the rails.

The Olds sure looks to be about 26" across, but it looks like the manifolds sit a bit higher and wrap a bit tighter.  The 454 must have been designed to sit down in these frame rails as well, so I'm wondering if it's close to the same size as the 455?  

I've been told that the motor mounts are located similar to the 350, different inserts possibly.  When I strip down this '72 Olds "98" LS - I'm gonna take everything in the engine compartment, AC, PS, Vacuum setup, motor mounts.  It has the TH400 like my pickmeup, so that's a bonus.  Plus the old boat has <30000 miles on it, engine/tranny might be in great shape.  And if it ain't it was 200 bux for everything.

Will it fit?  
Will it destroy my 12bolt rear?
Pretzel my driveshaft?  
Make my truck do wheelies?

Edited by: shpark2 at: 3/10/07 2:01 pm

Title: Re: '72 455 Olds Rocket IN, 350 OUT
Post by: BILTUP on March 10, 2007, 04:34:00 pm

Highly doubt it on the wheelies!

Title: 455 Olds
Post by: 123 pugsy on March 10, 2007, 08:11:00 pm

It will fit. I dropped one in my '79. It came from a '74 wagon. With the brackets and motor mounts from this car the bolt holes lined right up with the holes marked for 6 cyl. Only problem with this is the tranny is so close to the firewall that you have to drop the tailstock down with the engine pointing up to tighten the bellhousing bolts. Just make a spacer from flat steel stock to move the tranny mount to the right place. If you do this , the back of the heads may scrape against the firewall.I had to knock The firewall  back in 1 spot  after I installed it.

Edit: Forgot to mention I made custom headers,so not sure about the stock manifolds.

Pugsy

Edited by: 123 pugsy at: 3/10/07 8:19 pm

Title: Re: 455 Olds
Post by: shpark2 on March 12, 2007, 07:44:00 pm

Thanks for the info man, nice work you do on headers I might add!!

Title: Re: 455 Olds
Post by: 1976Scottsdale on March 12, 2007, 11:54:00 pm

All bow to the king of stainless.

Title: Re: 455 Olds
Post by: 123 pugsy on March 13, 2007, 11:45:00 am

Thanks. I work with stainless everyday.
Those headers come down and hug the block pretty tightly for frame clearance.

BTW,I wouldn't do this swap again. I would go with a 454 before I did a 455.

You'll also need a longer battery cable to the starter. Its on the other side.

Title: Re: 455 Olds
Post by: Fast68 on March 15, 2007, 05:09:00 am

350 olds diesel mounts work, ones for the 78-84 pickups, factory

and the manifolds too, they were dual exhaust type

i have a pair from an 81 pickup 350 diesel,, want pics ?

alot of these diesel pickups were th350 with 10 bolt univeral bellhousing pattern to fit all the gm 90 degree pattern engines, i still have the one out of the same 81 truck,


good luck