Mark71

So, I was talking to a guy I met who has a 1985 Chevy C10 with a 305 Chevy in it (carb'ed, AIR injection, bone stock). We got to talking when he saw my 71 Cutlass Convertible and he was asking how much work I've done on it myself.

Anyhow, I told him I was rebuilding a 69 Olds 350 for my first-ever engine rebuild. He asked me if it is possible to put an Olds engine in a Chevy truck (pointing to his). His 305 runs like a champ, but... it got me thinking anyway.

I know it is possible - with enough money and time, anything is... But neither of us are Jay Leno. Cash is always an issue.

How much fabrication would it take? Would it just be a motor mount swap? Are there conversion mounts that can be used? What about exhaust? He'd need Olds headers that are deep enough for the truck frame, right? Anything else I am not thinking of?

He's got a TH-350C with the "corporate" case, so I guess that's not a problem. It is a 10 bolt, 8.5" out back.

Please, no one tell me that I can/should put a 305 Chevy in an Olds.

Olds_71_442

I have a 455 Olds that I got from a friend who was trying to put it in a mid 1980s Chevy pickup. He tried to fit it, but there was something about the steering that became a problem for him. So he gave up and put the engine for sale. That's how I ended up with it.

I had the 455 before I bought my '71.

But........like you said, anything is possible if you're good at fabricating.

joe_padavano

Yeah, GM did it from the factory. OK, it was an Olds 350 diesel, but that's externally the same as any other SBO. If you can get the diesel frame mounts, this is a bolt-in.

garys 68

Since I'm a guy who put an LSx in mt 72 Olds, I'll take this on.
The frames for the A bodies have both the GM and BOP motor mount holes in the crossmember. Probably because the same factory made both frames. There are also quite a few adapters for the GM in BOP vars.
I dont recall any Olds trucks from that era, so doubtful the frames are drilled for both and may not be compatible to be redrilled. Olds mounts might be too far back and low. So some fabrication of mounts/crossmember may be required...which may put it out of the area of "practical".
If you have to move the engine, you're looking at a custom driveshaft. Not expensive, but again, why bother with the Olds motor.

Octania

I did a 330 into a 67? 69? Chevy truck yrs ago

As I recall I had to cut away the trans crossmember and weld in my own, and set Olds motor mount pads onto the frame and secure them. Fabricated exhaust. changed driveshaft length. Not all that bad with a torch and welder.

garys 68

GM used the Olds diesel in their trucks? Never knew that.
Was it as popular in trucks as it was in cars?

joe_padavano

The Olds 350 diesel was used in Chevy and GMC pickups and vans from 1977 through 1981. The 6.2L diesel replaced it in the 1982 model year. The Olds diesel frame mounts work in any 1973-1987 Chevy/GMC pickup (and the 88-91 R/V old body style trucks as well). With these mounts, any 1964-1990 Olds V8 bolts into a Chevy/GMC pickup.

Porter858

I have a 79 Chevy truck that came with the 350 olds diesel. I put a 455 in mine and it was by far the easiest engine swap I ever did. I didn’t have any interference with the steering, and being a diesel truck it came stock with the hydra-boost brake system. The only modification I had to make was on the truck’s A/C bracket.

I used 1 ¾” hedman headers for an A-body, and on the passenger side they come within 3/8” of the frame, but they don’t rub. The diesel trucks came with the TH-400 with the Olds bolt pattern, and the collector on those headers came very close to running into the cross member, so I had to weld my pipes at a slight angle for clearance.

Years ago I did another 455 swap into a diesel truck using manifolds. The factory 350 olds diesel manifolds have the same port size as a 455 manifold, but they turn straight down. I don’t think I could’ve used a stock car manifold on the truck.

I heard or read somewhere that LMC or one of those companies was reproducing the frame mounts for the diesel trucks, so if that’s the case, it wouldn’t be too bad at all.

It used to be one of my favorite swaps, since the diesels rarely lived more than 40-60k miles, I could buy these trucks in great shape with low miles, granted this was 15+ years ago. They even made some shortbed trucks, although I’ve only seen 2 ever, and never could find one to buy.

My 79 still only has 69k miles on it and it was a fully loaded Silverado with factory power windows, locks, A/C tilt column, delayed wipers, and the benefits for the diesel package where nice too. It came with a large tank 4 row radiator, engine oil cooler, hydra-boost brakes, wider rear brake shoes, heavier coils, large dual fuel tanks, etc.

olds 307 and 403

I put an Olds 307 in place of a sbc in my old 78 1/2 ton. I just welded the B body frame mounts to the engine cradle. I also used Flowtech A body headers. Close to the frame, ground the A arm bolts for clearance, very close. I also notched the trans cross member. The trans is dual pattern? If not you need an adapter. I put an Olds 350 in my 94 4x4, kept the TBI too.

Olds_71_442

My Dad bought new, a 1978 half ton Chevy with the Olds diesel in it. It had less than 25,000 miles on it when it blew the crank through the front of the engine. I was with him when it happened. He was only doing 15 mph on a dirt road.

Olds_71_442

I have a question.......did any of these Olds diesels come in a 4X4?

Porter858

As far as I know they didn't make any 4x4 with the olds 5.7 diesel. I've never seen or heard about one. Joe might know for sure on this.

I bought mine from the original owner, and if I remember right it broke the crank at 40k, then blew the head off at 60k. The guy was so disgusted with it, he damn near gave me the truck.

If I remember right, I think they were something like 22.5:1 compression, non-turbo of course. If I had to find a bright side to that horrible idea, they did get good mileage for their day. I want to say they had two 20 gallon saddle tanks, or maybe 18 gal, I can't remember for sure, but my friends truck before it blew up the last time had a range of just over 800 miles on a long trip even loaded.

Olds_71_442

I was asking about the 4X4 diesel because my friend was trying to fit my 455 in his truck and it was a 4X4. He said something about the steering shaft wouldn't let it go in. I don't know all the details. I just wanted the engine and didn't care if it fit in his truck or not.

As for my Dad's old truck, he traded in the truck when it was only 8 months old. The guy who got it after him had the head blow off too as well as the transmission and rear end letting go. Not to mention that the truck was starting to rust when it wasn't yet a year old. After the diesel, my Dad bought a 1979 Ford 4X4 which he loved and kept until he passed away.

rdhigh1974

Ive got a 78 Cheyenne shortbed version, also had duel tanks. Have a 72 olds 350 with the 7a heads on it. I just pulled it to clean it up and fresh paint and gaskets. Im trying to fi d some headers that I can put right in without having to cut or weld.

oldsmobiledave

You will have to use existing headers & cut & relocate tubes or just buy flanges & build your own. Drop in headers do not exist.


When I put headers in my 455 powered 1980 GMC I used Headman A body headers. The passenger side is easy but the driver's side is lots of work.

This was a 5.7 diesel truck. The diesel lasted 186,000 km and gave way to two different 350 Olds (1969 350 & a 1972 350) prior to me buying it. Since then it has had 2 different 455s & a T400. There is now 502,000 km on the truck.


truckheaders005_800x600.jpg


truckheaders007_800x600.jpg


truckheaders009_800x600.jpg


truckheaders020_800x600.jpg


455OldsinGMC005_800x600.jpg


RickysTruck.jpg

rdhigh1974

Thanks. Looms great. Ill post some pics when I get a chance. Are the heads on yours the same as smallblock? Ie, the 2 ?xhaust ports on the manafold have a shared port, and even on the heads it it wont seal between the two. I wanted to put headers on but cant afford it right now. The bolts on the manifolds are shot on both sides. Drilled, tapped, not going to work, studs on LH are one with the manifold now. Either way they have to be replaced so I have to go ahead and get the headers now.

nonhog

oldsmobiledave, Have any pics of header mods? Don't really see anything obvious in the pics above.

oldsmobiledave

Look closer at the tubes on the passenger side nearest the fire wall. The back two were cut & re-routed & welded. The passenger side is literally a drop in fit. Remember this is BBO Headman A body headers on a BBO.

cherokeepeople

when i put my toro gt engine in my 79 crewcab i used some a body hooker comp headers.i had to grind out a notch on the pass side of the frame but if memory seres me the drivers side needed nothing.also if you use 350 frame mounts the engine will set a little higher then the 455 mounts.also the motor mounts are taller on the 350's so you can gain a little more room.but well worth the time.they run smoother cooler and get better milage then the 454 plus under hood heat is cut in half.

Redog

I don't see why not. I was reading over on ROP a few months ago that people are buying a 1st gen Bravada and swapping Olds motors into them with no problems or major mods.

HDLLC

Newbie here, but seems I stumbled onto just about what I was looking for on information about a possible swap of a 350 Olds into my 72 C10.

I have a great running 79 Delta 88 with good transmission too, but really could use the motor/trans in my C10 pickup. Your post above says 73-87 would be easy with the diesel motor mounts - what problems or potential snags am I looking at on a 72 C10?

Thanks in advance for any help with this!

--Jeff

toymobile

I put a 403 in a 85 Toyota Celica with T400 .

Sure was fun to drive. My user name tells the tell.

Beenz

I'm doing a 79 c10 with a Olds 350 5.7 gas .Converted. and am stuck with what to do with the exhaust .can't use stocks Olds because of how the flange turns straight down right ? And I read everywhere that headers won't clear certain parts ..I don't have the 1600 do spend on custom headers and don't want to use these **** stock manifold. ..what to do .

lemoldsnut

put a 455 in a suburban 4x4 many years ago. we used two left B body big block manifolds. the center dump style. had one we used hooker headers for a mid 70's B body car as well.

Factory diesel manifolds should be a bolt in with what you are doing. Exact same block externally.

olds 307 and 403

Sanderson or Hedman shorty headers will fit. I used Flowtech A body SBO headers. Just ground down the nuts on the A arms as they barely touched, didn't want to dimple ceramic coated headers, should have, they were full of rust pin holes a year later in the ceramic. Sorry I missed this.

Reinah817

I have a 91 chevy extended cab and an olds 350, the engine was for another project that I got rid of. The engine is a monster. What exactly did you do to put the olds 350 into your 94 chevy? Any help would be greatly appreciated.

olds 307 and 403

You need 403 Trans Am mounts from a 77 to 79 to bolt in an Olds V8. I still needed big nuts to take up the space on one side but they worked fine and sat the motor level. I believe Year One sells new replacement mounts. They are a long bar and a solid mount piece design. Either manifolds or shorty rear dump headers are needed with custom downpipes on a 4x4. A 2wd will be more forgiving. Also a mini starter is needed on a 4x4 due to the front diff and routing down pipes.

wr1970

I had a 330 olds engine in a 65 gto 4sp loved it. No I did not do it i got it that way.

Reinah817

Thanks for the info, looking forward to getting started.

olds 307 and 403

Here is a link to the mounts.
https://www.yearone.com/Product/1967...-am-parts/rw81

olds 307 and 403

The 700R4 will need an adapter plate as well. I bought the cheap one. I could only get in 4 of the 6 bolts, this one is better.
https://www.summitracing.com/parts/trd-0061/
Also the 700R4 will need upgrades on anything more than a mild Olds 350. A 4L80E swap is a good idea with any significant power upgrades, the the 700R4, 4L60 through 70E are turds no matter what you do. A custom tune and a 454 TBI are good upgrades, the stock sbc tune is very cam duration limited.

Alaska442

The problem i am runningninto is the starter is on wrong side of chevy bell house. Does anyone know if the diesel engine chevy trucks wrre 4x4 and of them any manual transmission units for the SM 465. Ineed to find an olds 350 diesel bell house. Also the ball studd for the z bar is on the bell house

joe_padavano

The Olds diesel was not offered with a manual trans in the trucks, only with an automatic. The BOP bellhousing can be used, but the hole for the pilot is larger on the SM465. Unfortunately, if you machine the hole in the BOP bell to fit, it gets too close to the clutch fork pivot ball. A hydraulic throwout bearing fixes that.

Oldsguy

In reply to the op's question, I put a 455 in a late forties Oldsmobile. I think the differences of twenty some odd years of technology would count toward saying it can be done in a chevy or a buick or a pontiac or even a FORD or MOPAR if you want. Anyting is possible with enough determination and fabrication.