italian ice

Sorry if this general question has been addressed before. I'm going to swap a 455 Olds/TH400 into my newly acquired 1968 F85. Currently a 350/Jetaway. Goal is to build a "sleeper" Cruise Nite car, with the 455 made to look like the stock 350 to the un-trained eye. Including gold color, Air Cleaner and cast exhausts. No intention to street race, just for fun.

Here are the questions:
Besides 442, what years and models of Olds make the best donors for both engine and trans, that is with the most desirable internals - crank, heads, cam? Also considering the easiest to swap in.

Can anyone recommend an Olds engine re-builder in the Chicago area? To refresh whatever power train I buy.

I believe the car currently has a 12 bolt rear. Can it be converted to a 3:91 Posi.? If so, what vendors can supply the posi. & gears?

Any suggestions for front brake conversion to Disc? OEM or Aftermarket suppliers? I'll be using 15x7 steel wheels.

If anyone can refer me to another post for some of these questions, that works too.

Thanks for your advice.

2blu442

The swap is pretty straightforward. Use the 350 motor mounts and all the pullys, power steering pump and AC if it has it. If you get a new water pump be sure and match the one on the 350 as they do have different lengths. There are several threads on this if you have time to use the search option to read through them.

Any 455 will work, the earlier years 1968-70ish will have higher compression, but if you rebuild it you can put whatever internals you want into it. The compression was changed by the piston dish not the heads. Any of the big block heads will work fine for you, A, B, C, D, E, F, G, Ga, H, Ka and even the J heads if you do some work on them. A lot of people favor the C heads but I don't know if you would really see a difference for a street driven car.

If it's the type-O as came in the car yes you can install a 3.91 posi unit. There's a couple guys on this site who sell those parts, or a while back WTony had a complete rear end for sale. Look through the Drivetrain/Differential and the parts for sale sections.

For details the disc brake conversion read through this thread:
https://classicoldsmobile.com/forums...sk-brakes.html

italian ice

Thanks 2blu. That's the kind of advice I'm looking for.
Got a nice F85 from Mich. So I passed on the red one up your way.

italian ice

So thanks to the many of you who educated me on the fact that since I have a Canadian built F85, my 12 bolt really is a 12 bolt (Chevy).

Yes, after reading some of those "Diff" related posts, I ran to the garage, jacked up the F85 and there it was, the "inverted V". I feel left out in a way, cause I don't have a type "O".

For street use I may keep the 350/Jetaway for a year or two. Assuming I'll eventually put in a stock 455/TH400, any recommendations on gear ratio and brand of internals to use? (Posi. unit and gears) Maybe my first thought of going with a 3:91 is too steep. Opinions?

BTW, gas mileage is not an issue!

Thanks guys.

507OLDS

Since you have the 12-bolt Chevy,the cost of building it will be cheaper,since there is a huge selection of parts.For your application,I would suggest a 3:55 or 3:73.You will be very happy with those.The 3:91's are too steep for your application.
As far as 455's go,any 68-72 will make a great core to rebuild.
We did somthing similar with a faded 79 Delta before.We removed the 350,and installed a mildly-built 69 455.We took some RTV with a fine tip,and made the "C" into a "6" on the cylinder heads.That car gave the Mustang guys the fits.

svnt442

That's evil Brian.

joe_padavano

Nice! I was thinking I could make a set of B heads into a 1 or a 3 with a dremmel tool, but your way is better.

italian ice

Joe, your prior posts helped in my "differential" education. Thanks,

Don't know my way around Olds, like I do Corvettes so this has gotten to be fun again - learning about all the subtle differences in the cars. Its like starting all over. And except for some of those $100,000 442 convertibles, there are still a lot of affordable cool Oldsmobiles out there.

joe_padavano

Glad to have helped. I didn't contribute here because everyone else had it covered.

italian ice

OK given these two choices for donor cars... 1. 1973 Olds 98 w/455 TH400 - good running extremely low mileage car... or, 2 1974 Olds 88 w/455, Dual exhaust, TH400 towing pkg, Posi. extremely low mileage running car.

Do either of these have the HEI ignition?, should they be able to run on current unleaded gas?, any preference regarding rated power or internals? given the fact that the 88 was set up for towing? My point is - this would be a cheap way of getting BB power without cost of engine rebuild.

Your comments and advice are appreciated.

507OLDS

Given those 2 selections,you would better off hopping-up your 350 for more power.I would not use either one of those as-is.They are more of a boat anchor in their current condition,and I would have them rebuilt,and fitted with the correct parts to make respectable power.The posi rear from the fullsize cars will not fit your car either.
In my opinion,if you are going to go through the process of doing the swap,and have your car apart,it only makes sense to have it apart once,meaning rebuild the engine.You will be happier when it's all done.Those two 455's might still run good,but they are 35+yrs old.You can't expect a lot from them.The cylinder heads on those are not the desired choice either.

italian ice

OK Brian, this is good. The answers to the dumb questions are helping me decide the best course. At this point I'm still thinking out the plan for the resto. I know my limitations regarding what I can/want to personally do myself. So what I ultimately need is a mechanic who knows Oldsmobile/GM A bodies of this vintage. The only work I can tackle myself is the cleaning stripping, disassembly and prep.

I have great trusted body & paint people who I intend to use, but the drive train & suspension work will have to be done by professionals. I think the next step is to identify someone in the Midwest who can do all the mechanicals, engine rebuild and changeover. Is there a short-list for these types on the site? I'll post that question in general discussion and see what comes back. Thanks

svnt442

Update your profile with your location. That will help a lot.

italian ice

svnt442

Done - FYI Chicago Suburbs

Thanks

italian ice

testing signature....

J-(Chicago)

If you order up all the parts from Brian or Jim, I could set up your rear end if you pull the housing and bring everything over.
As far as the motor goes, you should set a price, and horsepower goal first, and then we can better recommend a plan of action.
Your car is also already set up for a th350, no need for a 400. Especially A long tail one from a big car.

For example: 400 horse out of your 350 would probably be about 4-5000
Depending on your rear end carrier and condition of your axles, The rear end build could be between 500-2000 bucks.

italian ice

Thanks J, I may have to flip this to the Small Block section. Here's what I'm thinking:

Must run on Premium unleaded pump gas - willing to use Octane boost if necessary.
Externally must be 100% stock appearing (L34) down to valve covers, cast iron exhaust manifolds, stock air cleaner, distributor, coil etc. I'm willing to use any carb, as long as it won't be too obvious under the air cleaner, but Quadrajet is fine. Don't care about visible casting numbers or date codes on any of the engine parts. Single 4bbl. intake, preferably Olds aluminum (painted). Willing to switch to a 403. Hopefully use my heads with larger valves. (no restrictions as to any internal engine modifications) Change trans to an appropriately built TH350. Under car chambered dual exhaust. And appropriate (Chev 12 bolt) rear gear ratio. Overall rear tire diameter 28" 743 rev/mi. The car should be easily street driven/reliable, but with as an intimidating sound as possible - lumpy idle OK.

So how much do I have to spend? (or how little?)

thanks