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I have a 1949 fastback 76 that i am planning on dropping a 69 Delmont 455/th400 into. I have the engine and trans, and engine mounts that supposedly bolt the whole thing up. Is there anything i should be aware of? The mounts are from a 1954 88 with a 350 swapped in that i found in a junkyard, and the transmission mount is from a guy who did this very swap
Haha yea, i wasnt planning on using cut up tires for rubber. And yep, rewire and replace the old 6 volt system! The lever action shocks will stay until i can wotk out a better replacement
I have a 1949 fastback 76 that i am planning on dropping a 69 Delmont 455/th400 into. I have the engine and trans, and engine mounts that supposedly bolt the whole thing up. Is there anything i should be aware of? The mounts are from a 1954 88 with a 350 swapped in that i found in a junkyard, and the transmission mount is from a guy who did this very swap
You need to find out if the 49 and 54 frames are the same or close to it. You'll need 12 volts for the ignition and starter. You'll need a new drive shaft and bigger radiator. While "swap" sounds simple, it can be a little tougher. There are a lot of people on here with knowledge and can guide you. I have to give you a LOT of credit for keeping an Olds engine and tranny in it. Sounds like a nice project.
Haha yea, i wasnt planning on using cut up tires for rubber. And yep, rewire and replace the old 6 volt system! The lever action shocks will stay until i can wotk out a better replacement
Speedway has a lot of parts to hot rod the more vintage cars.
Once i get it bolted in ill take measurements for the driveshaft, im really glad its not a torque tube. I found an aluminum radiator that is advertised to bolt right in too! Im hoping to use a mechanical fan but i could stomach an electric if need be. I took pictures and measurements and i think the frames are indeed close enough to work, but yea im hoping someone "in the know" will chime in. I put a chevy 350 in my 1951 chevy 3800 so i have a bit of experience with swapping but only that much. Yep im determined to keep it Olds powered!
Once i get it bolted in ill take measurements for the driveshaft, im really glad its not a torque tube. I found an aluminum radiator that is advertised to bolt right in too! Im hoping to use a mechanical fan but i could stomach an electric if need be. I took pictures and measurements and i think the frames are indeed close enough to work, but yea im hoping someone "in the know" will chime in. I put a chevy 350 in my 1951 chevy 3800 so i have a bit of experience with swapping but only that much. Yep im determined to keep it Olds powered!
I met a guy at a local car show last summer. He transplanted a similar engine/trans in a 54 and was getting 20 MPG on the road with 3.08 gears.
Thats amazing actually, wow! I intend to have my car be a little speedy so im not sure if ill do 308s or just leave the stock ratio, would a 455 have enough grunt to accelerate the car even with 308s?
, would a 455 have enough grunt to accelerate the car even with 308s?
Your biggest problem will be roasting the right rear tire .
The '49 Olds offered six rear end ratios . 3.23 .3.42 ,3.64 ,3.90 , 4.10 , & 4.30 .
The first two or three were for Hydra-Matics , and the rest for sticks .
Posi wasn't available until 1958 . and no , posi units will not swap into pre - 57 axles .
The factory set up is the 257 straight 6 with 3 on the tree. I figure ill have to swap the rear end eventually to get posi, but till then, like the lever action shocks, i guess ill just deal with it!
You probably won't have much of a decision where or not to change different rear ends... That 455 will make the decision for you. Doubtful that rear end can take the strain a 455 will give it. They were strong for there time but not 455 time...... Tedd
Well ive never had a big block car so ill have to see. Im hoping the tires give away before the rear end does, i wont be running big meaty tires just 235s
Stock ratio for a 1949 Olds 76 with stick was 4.10 .
It may have optionally a 4.30 .
A 3.23 or 3.08 differential center section from an automatic car would give you better mileage .
1947 thru 52 should swap in easily .
The stock rear should be OK , if, you avoid abuse and burnouts .
Well ive never had a big block car so ill have to see. Im hoping the tires give away before the rear end does, i wont be running big meaty tires just 235s
Better start lookin for a 59-64 full size Olds rear end. Measure up the rear end you have now. You'll only have to make a driveshaft once. Monzaz (JDRace.com) on this site can build you a posi rear end.
Last edited by OLDSter Ralph; January 10th, 2020 at 01:09 AM.
Reason: typo
I apologize for the newbie question, would that be very difficult to swap? And should i try to keep the trailing arm/coil spring design? In my reading online Pontiacs had a "Wide Track" design so their rear ends are about 62-63 inches wide while the 59-64 Olds was about 61-62 inches.
I apologize for the newbie question, would that be very difficult to swap? And should i try to keep the trailing arm/coil spring design? In my reading online Pontiacs had a "Wide Track" design so their rear ends are about 62-63 inches wide while the 59-64 Olds was about 61-62 inches.
I'll give you benefit of what I recall. I am sure there are better versed people on CO. I am assuming you have a leaf spring rear axle housing. I am basing the info below on Oldsmobile only, because Pontiac had the "wide track" thing going on from 1959 onward.
1. During the 57-64 years they changed from leaf spring to coil spring/control arm mounting.
2. 57-58 had different spline count. "Anti spin" (posi) was not available til 1958. 59-64 had a different spline count.
3. All the center sections ("pumpkin") will interchange between any 57-64 axle housing.
4. Axle length and spline count is the variable. Special axles are available (Moser, Dutchman) for a 59-64 "pumpkin" when installed in a 57 housing.
5. Jim can provide the "Anti Spin" (posi) and build it for you if all you can find is an open (one wheel spin) "pumpkin".
6. There are a couple different "Anti Spin" units and parts are available for one of them more easily....)I think the 63-64 Eaton). Monzaz (Jim at JDRace.com) is your best source for information. He is considered the "rear end Guru" on this site and is very knowledgeable.
I just thought of 1 more thing. The mounts shown in my first post on this thread, bolt to the side and front of the motor. The transmission mount i have is for the tailshaft. Do i need side mounts? Or are the front mounts enough? And does anyone recognize where those engine mounts came from anyway? Certainly not stock for 54!
I just thought of 1 more thing. The mounts shown in my first post on this thread, bolt to the side and front of the motor. The transmission mount i have is for the tailshaft. Do i need side mounts? Or are the front mounts enough? And does anyone recognize where those engine mounts came from anyway? Certainly not stock for 54!
Think in terms of a triangle for mounts to minimize engine/transmission rotational movement. While you have two mounts on the front, they aren't very "beefy". Two engine mounts on the front and one on the tail shaft mount will work.
........Just my two cents worth.
Sorry Ralph , 1939 thru 50 Olds had coil springs in the rear .
In '51 they went back to leaf springs and in 1961 they went back to coil again .
Charlie, Thanks ! I knew my '57 had leaf springs and my '64 Starfire had coil springs.
Charlie, any suggestions about which year rear axle housing would transplant into a 1949 "model 76" easiest ?
Oh yes yea i meant would i need something like bellhousing mounts in addition to the front engine and tailshaft mount. My thinking was that from the front of the engine to the tail of the transmission is a lot of space to have no central support
any suggestions about which year rear axle housing would transplant into a 1949 "model 76" easiest ?
A '57 or '58 axle is probably closest in tread width to the '49 .
One would need to find a good welder / fabricator to remove all the spring perches and brackets from both axles and weld them back on the later model axle .
Personally , I feel that the '49 axle is strong enough for the stock two barrel 455 the OP is putting in . It's only 310 HP not 365 as stated .
The fact that it's an automatic trans helps too.
A switch to a Hydra-Matic center section ( like 3.08 or 3.23 ) would be best .
A 455 with 4.10 gears would give terrific acceleration , but the gas mileage would suck .
A '57 or '58 axle is probably closest in tread width to the '49 .
One would need to find a good welder / fabricator to remove all the spring perches and brackets from both axles and weld them back on the later model axle .
Personally , I feel that the '49 axle is strong enough for the stock two barrel 455 the OP is putting in . It's only 310 HP not 365 as stated .
The fact that it's an automatic trans helps too.
A switch to a Hydra-Matic center section ( like 3.08 or 3.23 ) would be best .
A 455 with 4.10 gears would give terrific acceleration , but the gas mileage would suck .
eventually im going to build up the 455 for more performance, but till then if i can just get by with the stock 49 axle i think ill do that.
I have been think of this the swap only 1950 88.
does any one have experience with modifying the lever shocks by adding regular type shock. mine are weak and make for a bouncy ride. any ideas , or pics appreciated. Allan
I'm using a 68 Olds vista crusier frame for my 50 88 coupe. The frame is 121 wheel base and the coupe is 120 wheel base. I think i can fudge a little .
The stock rear will work great. the problem you are going to have is axles. the 10 spline just don't hold up. they twist and eventually break off.
you will have no problem for a while. Brake stands and hard shift 1st to second shifts will catch up to you.
I'm with you on the very front mount all the way to the trans mount. I used flat stock weld to the cross member with a tube welded on the plate, back to the second mount holes on the block.
I used motor mount #2261
That carries the weight of the engine, takes the weight of the trans bell housing.
I converted mine to late model power steering. I've seen some make brackets from the frame to mount rack and pinion.
What are your plans for the six cylinder. I would like just the cylinder head. It would be very cool as wall art.
Good luck. It will be a test of your welding skills.
Gene
do you have any pic's of the engine mounts from the 6 cylinder.
May be able to work a way to use the mounts from the six.
send me pic's of the six cyl mounts in the car. send to, gene@oldsmobileonly.com
For the sux cylinder, id really like to sell the whole thing to someone who would use and take care of it. Ive thought about just grabbing the cylinder head off as well, but, then itd be incomplete and somehow even harder to sell. The engine mounts for the straight 6 were just 2 bolts directly under the harmonic balancer, so thats a no go. I really need to de-rust the poor car, its rougher than i remember a year ago. POR15 perhaps!
I don’t blame you. It was only a thought. I’m sure somebody will use the engine.
in the pic of when you got the mounts, look like a brkt came off the frame towards the engine.
You understand what I was saying about making brackets from cross member to the middle mount holes on the block.
do you have a pic of the trans crossmember?
I did a compression test on the 455, no compression in 2 cylinders. Checked inside and yea its gonna need a full rebuild. So i went and got a 350 (Olds of course!) to bolt in for the meantime. With the custom mounts id miraculously found over the last 2 years it went very smooth! More updates to follow hopefully this summer!
I don’t blame you. It was only a thought. I’m sure somebody will use the engine.
in the pic of when you got the mounts, look like a brkt came off the frame towards the engine. You understand what I was saying about making brackets from cross member to the middle mount holes on the block.
do you have a pic of the trans crossmember? Gene
Originally Posted by Lance Johnson
I did a compression test on the 455, no compression in 2 cylinders. Checked inside and yea its gonna need a full rebuild. So i went and got a 350 (Olds of course!) to bolt in for the meantime. With the custom mounts id miraculously found over the last 2 years it went very smooth! More updates to follow hopefully this summer!
The front engine mount you used also needs to have a rear mount to limit rotation of the engine as suggested by 64Rocket. Look at Charlie Jones thread about restoring a 63 Oldsmobile pics. The front engine mount points on the frame are not far enough apart, in my estimation.
I put a mildly built 455 in my '48 model 66, aluminum aftermarket radiator, custom mounts, modified drive shaft, same suspension and rear end. It roasted the rear tire with ease so I stayed out of it. Sold it a few years later so by now if it is still on the road the read end has been replaced or repaired.
I suggest you make sure the drive shaft will not hit the “X” member when you lift car and the rear wheels are not supported
i did the same on my 50 Olds coupe. The short shaft T350 , when I lift the car on my lift the drive shaft hits the cross member. I think if you use a long shaft T400 would fix the problem.
I have to disconnect the drive shaft before I put it up on lift. I found out the hard way, Bent the drive shaft just little dent, but had a vibration.
I would suggest a mount of some type attach to the bell housing of some type. The way you mounted, that is a long distance to be unsupported . The original set up had a front mount and a mount at the bell housing to carry the weight.
maybe use the factory cross member with metal bolted to where the trans is bolted to the engine and down to the cross member. Just my thoughts.
I had to use a th400 short shaft to make it fit, otherwise the yoke wouldve been nearly inside the x member. But Ill double check to make sure the driveshaft doesnt hit the x member before i finalize it. also, I think i will put some mounts for the trans bellhousing for more side-stability. looks like something i will have to fabricate
January 9th, 2020, 12:44 PM
