Swap 394/350 Olds of course

Swed Olds · 08-03-2007, 01:11 PM

Just a little question, has anyone done an exchange between a 394 to a 350? Have maybe a little thought of replace my broken 394 and the tragically slim jim who only use two gears, with an 350/350 drive train. How much job is it? I´m not sure yet if I should do this or rebuild my 394 and hydramatic. Any ideas what’s the cheapest/easiest way would be.

88 coupe · 08-03-2007, 04:35 PM

http://www.classicoldsmobile.com/for...4-1962-a.html?

As it applies to you question, there is no difference between a 350 and a 455.

If I could do it over, I would still have the 394/Hydro in my Grey Coupe, and the 455 would have gone into my boat.

Norm

Olds64 · 08-25-2007, 03:47 PM

I have been considering a similar swap in my 64 98. I think it would be cheaper in the long run to rebuild a 350 / 455 and TH combo than rebuilding a 394 and Slim Jim. Actually, I KNOW it would be cheaper. I have been pricing rebuild parts for the 455 and 403 and they are much cheaper than 394 parts. I rebuilt the 394 in my 98 years ago and couldn't get the parts I needed to do the rebuild the right way (at least not at the price I wanted). I didn't put new valve train parts into my 394 and now I am paying for it with valve noise. The only problem with using a 350 / 455 is that it would take alot of work to get the engine and tranny to fit.

59-59-59 · 08-30-2007, 10:36 PM

"I did a 425 swap into a '57 Olds 98.. It wasnt that bad!!. The major thing to get absolutely perfet is welding in the motor mounts to accept a big block olds. Everything else was straightforward.."

Oldsguy · 08-31-2007, 04:35 AM

I just spent four days with the help of my best friend (35 year experience mechanic/welder) fabricating motor mounts and installing a 455 into my '46 Olds. We had not lift, used four jackstands; no air, used electric tools; did have a welder, had to make a 25 ft 220 extension cord; and no patterns or plans from someone else who had done it before. Pretty satisfied with how it turned out. My biggest obstacle now is getting the driveshaft to fit into the TH400 tailshaft. Had it cut to fit with correct slip yoke but ran into some unexpected problems. Nothing a grinder and two hours won't fix though...

Some day I might convince my friend to post all the pictures of the job and make a story about it here..

I just realize what I did, accidently edited your post instead of making mine after it. SO SORRY! With mod tools sometimes stupidity reigns. There is no way for me to retrieve the rest of your post to my knowledge....again sorry.

Trailermann · 09-12-2007, 09:11 PM

I just bought a 1962 Starfire. The original 394 was removed earlier and a 350/350 was put in. It has tons of power and very reliable. the engine if from a 1974 Olds and I am told it is a big block 250. Is that possible?

dar83501 · 09-12-2007, 09:21 PM

Don't think so. Big Block Olds was introduced as the 400, I believe.

joe_padavano · 09-13-2007, 08:55 AM

Quote:

Originally Posted by Trailermann

I just bought a 1962 Starfire. The original 394 was removed earlier and a 350/350 was put in. It has tons of power and very reliable. the engine if from a 1974 Olds and I am told it is a big block 250. Is that possible?

No.

Olds made a small block from 64-90 and a big block from 65-76. The only fundamental external difference is that the big block has a taller deck height (to accommodate the longer stroke) and thus a wider intake and different exhaust manifolds.

Small blocks are 260, 307, 330, 350, 403

Big blocks came in 400 (short stroke), 400 (long stroke), 425, and 455.

08-03-2007, 01:11 PM	#1 (permalink)
Swed Olds Junior Member Join Date: Jul 2007 Posts: 6	Swap 394/350 Olds of course Just a little question, has anyone done an exchange between a 394 to a 350? Have maybe a little thought of replace my broken 394 and the tragically slim jim who only use two gears, with an 350/350 drive train. How much job is it? I´m not sure yet if I should do this or rebuild my 394 and hydramatic. Any ideas what’s the cheapest/easiest way would be.

08-30-2007, 10:36 PM	#4 (permalink)
59-59-59 Senior Member Join Date: Sep 2006 Posts: 183	"I did a 425 swap into a '57 Olds 98.. It wasnt that bad!!. The major thing to get absolutely perfet is welding in the motor mounts to accept a big block olds. Everything else was straightforward.." Last edited by Oldsguy : 08-31-2007 at 04:33 AM.

08-31-2007, 04:35 AM	#5 (permalink)
Oldsguy Administrator Join Date: May 2004 Location: Lees Summit MO Posts: 2,859	I just spent four days with the help of my best friend (35 year experience mechanic/welder) fabricating motor mounts and installing a 455 into my '46 Olds. We had not lift, used four jackstands; no air, used electric tools; did have a welder, had to make a 25 ft 220 extension cord; and no patterns or plans from someone else who had done it before. Pretty satisfied with how it turned out. My biggest obstacle now is getting the driveshaft to fit into the TH400 tailshaft. Had it cut to fit with correct slip yoke but ran into some unexpected problems. Nothing a grinder and two hours won't fix though... Some day I might convince my friend to post all the pictures of the job and make a story about it here.. I just realize what I did, accidently edited your post instead of making mine after it. SO SORRY! With mod tools sometimes stupidity reigns. There is no way for me to retrieve the rest of your post to my knowledge....again sorry. __________________ Dan '46 2 door

Thread Tools
Show Printable Version Email this Page
Display Modes
Linear Mode Switch to Hybrid Mode Switch to Threaded Mode

08-25-2007, 03:47 PM	#3 (permalink)
Olds64 Landyacht Club President Join Date: Jul 2007 Location: Lawton, OK Posts: 1,344	I have been considering a similar swap in my 64 98. I think it would be cheaper in the long run to rebuild a 350 / 455 and TH combo than rebuilding a 394 and Slim Jim. Actually, I KNOW it would be cheaper. I have been pricing rebuild parts for the 455 and 403 and they are much cheaper than 394 parts. I rebuilt the 394 in my 98 years ago and couldn't get the parts I needed to do the rebuild the right way (at least not at the price I wanted). I didn't put new valve train parts into my 394 and now I am paying for it with valve noise. The only problem with using a 350 / 455 is that it would take alot of work to get the engine and tranny to fit.

09-12-2007, 09:11 PM	#6 (permalink)
Trailermann Beautiful 62 starfire Join Date: Sep 2007 Location: Paortland Oregon Posts: 1	I just bought a 1962 Starfire. The original 394 was removed earlier and a 350/350 was put in. It has tons of power and very reliable. the engine if from a 1974 Olds and I am told it is a big block 250. Is that possible?

09-12-2007, 09:21 PM	#7 (permalink)
dar83501 Brewsmobile > Bluesmobile Join Date: Sep 2007 Location: Lewiston, Idaho Posts: 272	Don't think so. Big Block Olds was introduced as the 400, I believe.