So there is a guy selling a 1965 F85 with the old V6 in it.

I have a 66 425 and a spare tranny sitting in my shed.

Can the 425 be dropped straight in to the F85?

Thanks

 

You'll need to change the frame mounts from Buick to Olds. If you get correct 1965 frame mounts then you need Anchor 2261 motor mounts. You'll need A-body exhaust manifolds, preferably W/Z manifolds. The TH400 will be a long-tail unit, so you'll need a custom driveshaft. You'll also need to drill the frame for the different trans crossmember location since the TH400 was not available in the A-body in 1965. Moving the crossmember means you'll need to change the front and intermediate e-brake cables. Get the ones for a 1967 Cutlass/442 with TH400 trans. Obviously you'll want a bigger radiator, and wiring will change since the starter is on the driver's side on the 425.

 

Great info and thanks for taking the time to post!

I would have thought the 425 would have slid right in. Thought I read they came with a 400 option and I figured that the 425 was the same external dimensions etc.

Seems the biggest issue though is really the transmission match

 

The v8 setup was changed to allow for the v6, because Olds did not manufacture a v6, they used the Buick engine in 65. What Joe is saying you will need to change it back to a v8 setup for the 425. You may get away with not having to change the radiator.

 

Makes sense. So what transmission would have come with the Oddfire V6? I assume it was the TH-300 Jetaway?

Conversely, what tranny came with the 400 set-up? I assume it was thus a TH-400?

Just wondering if the stock transmission (TH-300 Jetaway?) would mate to the 425 and if it could handle the 425 torque if it did?

Thanks!

 

I would drop the th400 it's really not that bad for a new driveline I was quoted 200.00 and to shortin the old was 85 with new u joints . Have not checked on brake lines yet I am sure prices change depending on shop and location

 

Olds DID offer the Buick V6 as the base engine in the A-body cars in 64-65. My parents bought one brand new in 1965. This was a factory installation and the V6 radiator WILL be too small.

 

He asked this.

I was explaining why you stated he needed to change frame brackets and engine mounts. That Oldsmobile didn't have a V6 of their own. Sorry for the misunderstanding.

On the radiator, since the OP is from Canada, I was thinking it may work.

 

The confusion is in this statement:

While you may not have intended it that way, the statement is worded in a way that implies the car was not originally a V6 car and may have come with a lager V8 radiator. It did not. I'm not suggesting changing anything "back", as the car came that way from the factory. The mounts and radiator will need to be configured from the factory-installed Buick part to the correct Olds parts.

Just trying to be unambiguous.

 

You do realize we can hit 104F in summer or 40C to us in Summer. We have the most extreme climate on the planet, +40 occasionally in Summer and -40 or more in the Winter. Our country is huge too, weather varies a lot, by a much as 50 degrees at times. At any rate, the V6 rad won't cut up here either.

 

That's what I get for thinkin!

I thought we had extreme swings in temp here in Texas, mostly in the off season.

 

The '65 F-85 used a different core support for the V6 than it did for the V8. While I have seen the V6 unit used in a V8 swap it was kind of a mess. You may want to compare the two and the radiator openings. It may be cleaner to swap the core supports depending on the radiator you plan on using. Also the battery tray is basically the same but the mounting brackets are different since it is on the other side. Moving it to the driver's side puts it closer to the starter on the V8.

Regarding the transmission. A Jet-a-way bolts right to the 425. I've done it before. It will probably last a week or two if you abuse it unless it is built for a big block. They worked fine behind the 400s but had additional forward and reverse clutches and the modulator and other parts were calibrated differently. I beat the snot out of my Jet-a-ways behind small blocks. The one in my '65 442 was not the original HD unit and worked for years . We took the 330 out of a '65 Vista Cruiser, dropped in a 425, and trashed the 2 speed within a couple of weeks. Better to upgrade. A TH350 easily bolts. The TH400 is almost as easy but as mentioned, requires moving the cross member back. Some of the newer overdrive transmissions are good choices but a little more complicated to install.

 

And for a trivial detail, the fuel line is a smaller diameter and I believe also on the opposite side than a V8. On a banzaii run you may run short of fuel without an electric fuel pump. Your brakes may be lacking as well.

 

That may be true, but it is unrelated to the V6 engine. All 1965 A-body cars (except the Vista Cruiser) got 9.5 x 2.5 front drums and 9.5 x 2 back drums.