# olds 455 in gto?



## chaz.kearns (Nov 19, 2010)

I just got a olds 455 for dirt cheap, and i was wondering if it was possible to put it in a 69 LeMans to make a GTO clone? I know there is a difference between pontiac and olds 455's, just dont know what exactly it is. I also got a transmission with the motor, i beliive it is a th400???

any help is appreciated.

C. Kearns
:cheers


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## PisnNapalm (Aug 28, 2010)

This site can help you identify the transmission.

Automatic Transmission Identification

About the engine though... I don't know.


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## starnest (Oct 27, 2010)

I am sure it is possible. In fact I'm fairly sure that the olds 455 will fit with few issues. I think the differences will be "correctness" issues. If the trans was from the same car as the 455, then it is most likely the TH400.

Basically the 455 is known as the BOP motor (Buick, Ols, Pontiac). The block is common to engines from 326 to 455 ci, major differences in heads for different displacement, compression (hp), and between Buick-Olds-Pontiac engines. Other differences for intake/exhaust manifolds and the accessory equipment.

Doing a good rebuild is not that difficult. Give consideration to better heads (aftermarket is probably the best bet), but do your homework first. There are some knowledgable Pontiac engine people at the hotrodders forum that will help you to identify the good original equipment parts (ie HP heads, etc) or the best of the aftermarket equipment for your engine.

Just so you know, in very few instances will a GTO clone bring the money. So plan to spend only for your own indulgence.


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## ALKYGTO (Mar 29, 2010)

OP, The Buick, Oldsmobile and Pontiac 455's, while all sharing the same cubic inch displacement are *completely different* engines. They do share the same bellhousing bolt pattern but that is it. No components interchange between makes engine wise at all. The BOP reference is correct but applies only to the tranny really. It will interchange, nothing else will. Motor mounts are even different.

GTO and Oldsmobile frames interchange, and yours is already drilled for the Old's motor mounts. When I took the body off the frame of my GTO the body mounts actually said Oldsmobile on them.

It's your car, do what you want, but the Old's is not an inexpensive motor to build and you would put just as much into a Pontiac and in the end the car would be worth more with a Pontiac in it if that's what your end plan is. :cheers


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## geeteeohguy (Feb 2, 2008)

ALKYGTO is 100% correct. An Olds engine shares nothing with the Pontiac except bell housing pattern. You can install it in your LeMans with a few mods. Not a big deal. As an aside, the Olds engine is a durable, strong runner.


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## chaz.kearns (Nov 19, 2010)

I dont plan on reselling the clone, just want it for myself. i want it to be a project for me and my son to start here soon. and the only reason i thought about the olds 455, is cuz i got the motor and the tranny for 125 bucks from a guy in mississippi.

thanks for all the help and info.


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## jetstang (Nov 5, 2008)

The olds 455 is a great torque motor just like the Pontiac, so will overpower the car at will. Just don't think you are cloaning anything as no Pontiac enthususiast is going to be tricked. The olds intake is 2' wide and looks nothing like the Pontiac motor. Beyond that it should bolt right in and I think all the Cutlass parts will fit correctly


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## ALKYGTO (Mar 29, 2010)

For Oldsmobiles, Joe Mondelo is the man. Or try **** Miller who also makes really nice bolt on suspension goodies for these cars.

Olds 455 motors are real durable.

What heads are on it. Big blocks use a letter (like C or F) and small blocks use a # to differentiate castings. 

If you are building the car for yourself Olds power could be real cool, but you'd have to build her strong to get around some of these Pontiacs. 



edit: I can"t believe they sensored "Richard" Millers name. lol


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## jetstang (Nov 5, 2008)

ALKYGTO said:


> edit: I can"t believe they sensored "Richard" Millers name. lol


I guess richard is the same as ****.. See if that gets edited..

Olds 455 is a great motor. I would use it as a father son project, just buy Cutlass parts and motor mounts. You got a smokin' good deal on the Olds motor.


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## sixeightGTO (Jan 25, 2010)

The Olds 455 is a strong motor. When I was seventeen my father and I rebuilt a 1968 Firebird with a 455 Olds in it. That car was way over geared it had a 4.11 posi. Scary quick and didn't even think about getting on the highway with it. Sounds like you got a great deal on the motor. Build it because as a father son project you can't go wrong. :cheers:cheers


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## BearGFR (Aug 25, 2008)

chaz.kearns said:


> I dont plan on reselling the clone, just want it for myself. i want it to be a project for me and my son to start here soon. and the only reason i thought about the olds 455, is cuz i got the motor and the tranny for 125 bucks from a guy in mississippi.
> 
> thanks for all the help and info.


Oldmobile 455's can be monsters. They share the same bore spacing as the Pontiac which will likewise limit the amount of overbore available. The path to more inches leads through "Stroke-ville". Joe Mondello is one of the recognized authorities on Oldsmobile power.
Enjoy the project with your son!

Bear


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