I'm thinking about picking up a '61 Olds 98 mordoor HT with a 394 and a bad tranny. Does anyone know what years/other GM makes are interchangeable? Can I easily upgrade to a later model Turbo 400? Also, the motor rear main seal is leaking. Can this be repaired without pulling everything apart once the tranny is removed?
I just finished our trans conversion to use a 350/400 turbo To all early Olds and its badass Nice -neat- clean, cause thats how we do it Just need to finalize price Will try to get pics by end of the week Tony 330-720-1282
Coldwar: Wrong again dude, he has a Roto 10 slim jim, not a DC hydro, Olds stopped using the DC in 60. The problem with 394's (as is the earlier rocket engines) is the cast in bell housing. It messes everything up as far as going to turbo 400's, 350's, et. al. The link above cuts the bell housing off the turbo transmissions and makes a small adapter to mate the engine to the trans via the front pump bolts. I guess it works, but cutting off the bell must be expensive. You have 3 choices that bolt up, your Roto 10, the dual coupling Jetaway from 59/60 Olds, or you could bolt a 52 to 55 Oldsmobile dual range hydro up if you get the crankshaft fitted with a pilot bushing, and have the earlier flywheel counterbalanced to the crankshaft. Other than those three choices which do not involve too much in the way of money, your options are going with the link mentioned. BTW: you could find an Olds stick bellhousing and mount a T10 4 speed, but that may be easier said than done. One other thing is the floorboard clearance, might have to pound it out a little if you go with another transmission. Good luck
The D-C Hydro should be an easy swap from any car equipped with the post-1959 version of the transmission. Worst case, you'll need a Caddy or Bonneville trans tunnel to go with it. Having had both out loose I'm just about certain the actual trans case bolt pattern is the same for both of them. I understand the Roto even slips if you use it as a boat anchor - I wouldn't rebuild it, myself.
Thanks guys, I think..... Hey CW and d2, what the heck is that all about? Can't we all just get along and help our motorhead brethren out without the bickering???? Sounds like I don't have a lot of options here with that 394 in it. How about a 455/T400 swap?
Sorry I offended you dude, and if I had put something like: any spring will affect the 1-2 shift points I apologize, but I meant the 1-2 shift valve spring. Iwill refrain from any mention of you or anything about you. good luck.
CurtRod58: I just got done apologizing to CW. I was simply noting the error, not criticizing. No big deal, I make mistakes too, but don't get overwhelmed by criticism as life is too short for that stuff. Getting to the real question, yes the Olds bell housing doesn't offer much as I had pointed out, and the narrow tunnel in the 61-64 Olds is just another issue to be resolved if you decide to transplant another transmission. The 455 and th400 would be a nice swap, but you have to make mounts(crossmember possibly) for the engine as the Olds mounted from a single point on the front of the engine, the torque mounts being on the bellhousing. What you are trying to do will require a new crossmember at the back of the TH400. So again this could turn into an expensive proposition.
I have never driven the car, I have only heard it run. The previous owner said the car does drive but it changes poorly between 2nd and 3rd because the carb works via the kick down rod off the tranny it affects the rpm when changing gear. The price was right so I just bought it and I figured I would troubleshoot it once I got it home. Here's a couple of pics,,,
voice of experience - I hired Tanson to do my tranny coversion on a 700r4. I have a 60 olds w/394. 3 month wait would have been a pipe dream. Tanson sends his work out to another shop and it took almost a year to get it back. I had them build mounts and sent them back. the second pair they sent out didn't even match each other! am making my own and had to do some mods as well. I had to notch the cross member so the torque converter would fit, then had to weld support brakets on the cross member to allow the mounts to hang off an inch towards the front, to match the original position. The drive shaft is headed out to a shop next week to get cut back a couple inches and replace the front yoke to match the 700r4. I had researched this issue long and hard and found a guy in Michigan (bendts? or Benson?) that NOW sells an adapter! I had called them early on and they told me they quit making adapters because Tanson had a supperior product. Well, as soon as I forked over the cash for Tanson, the guys in michigan came out with a new adapter plate. ugh. Anyway, there is a guy here who made a conversion in Niles Ohio that I thought wins hands down. Is that Goatroper02? I guess the bottom line is "there is no cheap solution". THe 350 swap should fit in the transom, but the 700r4 required me to cut and enlarge.
61 has a ladder frame, FWIW, shouldn't be frame issues, but could have trans tunnel clearance issues instead. Dual Coupling Hydro is far superior to the Roto-Hydramatic, and would have been original in a '60. I still want to see a 64-66 Buick TH400 out loose and compare the front bolt pattern to that on the iron adapter the Pontiacs used to bolt to the various Hydro transmissions until '65.
here is a link to the guys up north with the adapter... http://www.transmissionadapters.com/index.htm
From first hand experience and talking to others who have also dealt with Tony [Goatroper] you won't go wrong dealing with Ross Racing. Family operation, straight shooters, and his dad loves old Oldsmobiles.
looks like you got a pretty good deal. i've got a 61 also and it does the exact same thing between 2 and 3rd (it bogs down and then takes a second to pick back up) and i have not been able to find out how to fix it. any ideas?
Anyone out there have any experience updating to a newer Olds motor/tranny combo in these era Olds? The original 394 motor seems kinda tired and parts for these 394's aren't easiest (re: cheap) to come by. It only has 75K original miles but evidently sat unused for 20+ years.
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