Olds 425 engine

[bluesman79]

Hello g-body folk,

I just ran across a running ready to drop in Olds 425. I don't know much about this engine (I originally planned for a 455) but from what i've heard, the 425s are pretty badass and RARE!! The only problem is that it's $1k for complete engine. He has a video of it running and it sounds good and looks to be in good shape, is this too much to pay?? I don't plan on racing, but I wanted a torque monster to do burnouts and spin donuts with ease. Also, what transmission would you recommend to handle that amount of torque and still be able to cruise down the highway/freeway. I know this is a loaded question, but this is ALOT of money to shell out on a working man's budget, THANKS FOR ANY INFO FELLAS!!! 😀

My 1981 Olds Cutlass Supreme

 

[DoubleV]

$1k seems a bit steep, but then again if it's a low milage engine in great shape it could be very well worth it. Also depends on what all's included too. Any transmission can be built to handle big block torque so pick your poison. The TH400 would be your best bet for a cheap stock transmission but of course it doesn't have OD which can be a real pain if you're running steep gears. But seriously, donut's? Really? Donuts? C'mon man.... 😢

 

[Pohlcat]

Hell ya it has the forged crankshaft

 

[DRIVEN]

The 425 is a cool engine so I'd snap it up. I'd have a 200-4R built for it. If budget is a concern, a TH400 could be a cheap alternative.

 

[-83MONTESS-]

IIRC the 425 and 455 have the same bore so the blocks interchange. The crank in that 425 should be forged which is why alot of people like them. When I graduated high school my grandpa gave me a 425 Olds that sat since 77 as a project for college. I learned that Olds engines are too expensive for my budget right now so I pulled it apart and tucked it away for later 8) If it runs good and has low mileage I would seriously think about it.

 

[bluesman79]

$1k seems a bit steep, but then again if it's a low milage engine in great shape it could be very well worth it. Also depends on what all's included too. Any transmission can be built to handle big block torque so pick your poison. The TH400 would be your best bet for a cheap stock transmission but of course it doesn't have OD which can be a real pain if you're running steep gears. But seriously, donut's? Really? Donuts? C'mon man.... 😢

Yeah, i'm tryin' to light them things up man!!! It won't be often but I plan on gettin' that thing sideways!! :lol:

 

[bluesman79]

IIRC the 425 and 455 have the same bore so the blocks interchange. The crank in that 425 should be forged which is why alot of people like them. When I graduated high school my grandpa gave me a 425 Olds that sat since 77 as a project for college. I learned that Olds engines are too expensive for my budget right now so I pulled it apart and tucked it away for later 8) If it runs good and has low mileage I would seriously think about it.

I'm finding out REAL fast that these Olds engines are pretty damn expensive. I'm currently running an early 70s Olds 350 with 7A heads (but it's running poorly due to a bad carburetor and other things). I need that big block in my life bro!!

 

[bluesman79]

The 425 is a cool engine so I'd snap it up. I'd have a 200-4R built for it. If budget is a concern, a TH400 could be a cheap alternative.

Yeah, that TH400 is looking real good right now. But what do you call the auto shifter that you can slap and it changes gears, what company makes those? Also, how do you feel about adding a 5 speed manual transmission, it sounds like super fun, but I have no idea which one to get and if my stock rearend would hold up. THANKS again!!

 

[bill]

You cant buy an engine and rebuild it for that price.....sounds like a good deal to me.

 

[jae]

Yeah, that TH400 is looking real good right now. But what do you call the auto shifter that you can slap and it changes gears, what company makes those? Also, how do you feel about adding a 5 speed manual transmission, it sounds like super fun, but I have no idea which one to get and if my stock rearend would hold up. THANKS again!!

You can either get the Hurst Dual-Gate or other Hurst shifter that allows for manual "bump" upshift or the B&M Mega-Shifter.

For the 5-speed you have to ensure the crank is drilled for it as there needs to be space for the input shaft and the bearing in the crank. You will also need to ensure the bell-housing is for the BOP bolt pattern or you'd have to run an adapter plate. A TKO-500 or TKO-600 may be the way to go but think about the other components that are needed such as pedal assembly, manual vs. hydraulic throwout bearing, necessary hardware...not trying to sway you to an auto but just letting you know what may be involved.

As with others I say try to grab the 425 but try to ind out EVERYTHING you can about it before purchase