[ZnbOlds455]

I'm going to formally introduce myself now. I've posted a few times already. My name is Zack and I live in South Carolina. I acquired my dad's '65 GTO about a year ago and have only recently really been able to spend some time with it. It's not an original or #'s matching car, so I'm planning on a mile resto-mod.

My dad bought it in the mid-80's and took it apart for restoration. He sent the body and frame off for blasting and painting. That shop burned down and the car sat in insurance limbo for a couple years. When he finally got it back, it had been blasted and primed, but that's it.

The car came equipped with an Oldsmobile 455 out of a '69 something. I think it was a Toronado, but my dad keeps saying it was a 442. I'm thinking not since the exhaust manifold has 2 different outlets on the passenger side. My father-in-law went through the motor thoroughly years ago, and I've heard it run. It just ran on a bare frame, but I know it works. I'm guessing I'll have to do gaskets again when I get it running because it's been sitting idle so long now (12+ years). They did some sort of red/white/blue theme for some reason, so I'll be correcting that as I replace gaskets.

The TH400 transmission is in a similar boat to the motor - it's been rebuilt, but has been sitting for 12+ years. I have a Muncie M21 (my dad believes it's a Rock Crusher, but it's clearly an M21) that I may consider swapping in. It has a busted ear on the mounting flange, though.

The body was repaired and painted shortly after the motor. The paint will definitely need some refreshing. All the chrome is shot.

I may start a build thread, but it'll span several years. I'm in my 40's and have 3 kids ages 7-16. Here's she is in all her (not) glory.

[Lightfoot]

That's a pretty straight looking body. You say it was blasted and primed but it looks like Mayfair Maize. Is that epoxy primer?
If it is, what's the original color on the trim tag?

[Half-Inch Stud]

Greetings. My wheelhouse is 68 GTO, 69 Bird, and TH400 for Street/Strip/Concourse. My brother owned a Red 65 GTO, so i know they can be wonderful looking cars.

Get er done.

[FrankieT/A]

Looks like Mayfair Maze to me....Hard part's done. Christmas is coming so tell the family "No ties", just small chrome parts. In no time you will be driving that...

[tempest1964]

Nice project car. It does look like Mayfair maze. There is a wealth of knowledge here. This is a very good forum. If you can post a close-up of your data plate on the firewall, some of these guys can tell you some more info about how and where your car was built. Welcome!

[ZnbOlds455]

Thanks for the greetings. I've been lurking for a few months and doing a TON of research. As you can see, I've got my work cut out for me. I'm a novice to all this as well. I'm hoping my FIL can provide some guidance. He's basically been doing this type of work as a career for the last 15 years and as a hobby for 40 years. He's done Chevelles, GTOs (putting the finishing touches on a 68 now), Model Ts, C10s, and many more. I'll try to post some pics of his work when I can, just for kicks.

The car was originally a midnight blue. The primer was epoxy-based. I believe the paint was base/clear. It's very brittle. Any ding ends up chipping right through the paint. There are a couple of surface rust spots that have shown up where it got chipped in storage at my dad's and the doors interfered with the fenders.

[Baron Von Zeppelin]

Its a real GTO with the 5N code, thats good.
Charcoal Blue with Blue interior - that was Nice !
was a factory AC car with Automatic
Built at the main Pontiac plant July 2nd week - amongst the last 65 GTO's built.
Very late production before shut-down for retooling of 66 model production.
Someone might have account of when 65 production officially stopped.

E = Soft-Ray Glass ALL

2K = AC
2W = 2spd Auto
2G = Console
2P = Back Up Lamps (reverse lights in bumper)

5N = GTO

These are just the Fisher Body codes. So not a complete list of options.
And basically obvious already that it had these just by a quick glance at the car.
It likely had more options beyond these listed.

It looks like the softray glass might be gone from the side glasses, by the pictures.
It would be the green glass from the good old days ... and have Soft-Ray logo.

Welcome to PY Forum

[ZnbOlds455]

The owner before my dad bought it took a rattle can to the interior, so it’s mostly trashed. I think the dash and center console are salvageable. I liked the original blue, but my dad wanted the yellow from his teenager years. He’s been down once to help out. He dropped off the back seat and a few boxes of bits I haven’t yet gone through yesterday for my daughter’s birthday party.

I have a few parts for a 389 he was thinking of putting in. Right now that motor is just a stripped block. I don’t know much about it. The 455 was running well when parked. It turns freely still, so I’m sticking with it for now.

[Baron Von Zeppelin]

Try to look at the heads on the Olds engine.
If they have a raised cast letter of "C" - "E" - or "F" on them, its going to be a good one.

If you paint the engine the right shade of Light Blue for a 65 Pontiac, and chrome the valve covers, it might slip right by a lot of people.

The right style of air breather for a 65-66 GTO 4bbl Carter/AFB carb is also made in the version that will fit a Qjet carb (for a 67 GTO). If you wanted to really go after an original looking vibe under the hood... with the Olds engine.

[Half-Inch Stud]

Olds V8 Power is respectable. 403, 455 whathaveyou. 389 in parts helps tell a story.

[ZnbOlds455]

Originally Posted by Baron Von Zeppelin

Try to look at the heads on the Olds engine.
If they have a raised cast letter of "C" - "E" - or "F" on them, its going to be a good one.

Is this the "C" you are referring to?

[77 TRASHCAN]

Congrats on your 65 GTO. SInce we all now know it's a REAL GTO, that is COOL.
Oldsmobile had some different ideas on exhaust systems. I'm no expert but, most Olds engines had a crossover pipe that ran from one manifold to the other and then on pipe off one manifold only. These were stockish engines from the 70's. As for the engine being from a 442 or Toronado, I am no help.

I'm with Baron. paint the engine a Pontiac color, and run it like that. An Olds 455 is a VERY good engine

Carry On!!! A 65 GTO is an all time iconic car, Don't let it get away from you!!!

[Baron Von Zeppelin]

Originally Posted by ZnbOlds455

Is this the "C" you are referring to?

Yep
Its going to be from a 68 or 69 Fullsize Olds (possibly Toronado) with the exhaust manifolds you described.
Good engine, but high compression ratio like most all from back then.
We have a couple or few members who know Olds engines pretty well who could give you more ID help and Specs, etc....

I used to know the HP rating on that engine. Seems like 375hp zone
Almost bought one complete from breather to pan in a 69 Olds 98 for a friend who wanted a better engine for his 72 Cutlass Convertible 350cid.
He never put the $300 in my hand in time before it was gone.
Around the mid-90's

Olds had a 455 before Pontiac did, and before Chevy had the 454.
442 didn't get it until 1970 , they didn't use C heads in 1970 on 455, or later 455's. iirc
Just the early ones.
69 Hurst/Olds did get the 455 , but not sure which heads on those. But thinking they were "D".

[77 TRASHCAN]

Cliff likely has some answers for the high compression 455. I'd want his 2 cents, without doubt!!!

Baron, was it 68 when Olds got the 455???

[ZnbOlds455]

The GTO has been my dad's since 1985, so it's not going anywhere.

I know the 455 block is from late 68 based on the casting - 38M25924C. I've been researching on some Olds forums. I swapped out the old iron intake for an Edelbrock Performer. The crossover ports are blocked off by the gaskets. I have no idea which cam is installed. I think it's a Comp Mutha Thumpr, but the guy that built it (my FIL) can't remember. I'm hoping I can run it on pump gas, but I have no idea. I'm probably going to run a Holley Sniper EFI as well.

[Baron Von Zeppelin]

Originally Posted by 77 TRASHCAN

was it 68 when Olds got the 455???

Yep
and his is a 68 as noted by the partial VIN

I'm hoping I can run it on pump gas, but I have no idea.

Probably not safely with full ignition timing
Not unless FIL made pump gas provisions during the build.
He would remember that more than likely.
Special dished pistons and hardened valve seats.

a Mother Thump cam will probably make it even less pump gas friendly.
We do have some Olds specialists on here who can guide you pretty well about what you have , and suggestions on tuning it best for pump gas efforts.

It will probably need de-tuning on the ignition timing which will decrease overall power.

Or use lead additive and octane boosting (race fuel mix) and get the ponies kicking.

[400 4spd.]

BVZ is right about the 455 being in the Hurst/Olds during '69, so doubtful it's out of a '69 442. The 455 was standard in the Toronado for 1969, and in the 442 for 1970, nothing else offered. I actually owned a '70 442 that I ran a Pontiac engine in for 10 years. I was NEVER called out on it being a Pontiac engine.

[Baron Von Zeppelin]

38M25924C is the partial VIN ID stamp

3 = Olds (like 2 = Pontiac)
8 = 1968 car
M = the plant in Michigan ... Milborn or Mollyringwald or whatever the M city
25924C = the last digit should be a number - maybe 0 6 or 8
The last 6 digits of that cars VIN is what it represents.

[Half-Inch Stud]

Is this Rally Clock (dated Aug 64) for a 65 GTO? is avail.

[Jay S]

Looks like you have a great project. IRC, the Olds 455 in the tornado ran a little shorter profile intake manifold with different exhaust manifolds to miss the transaxle. You should be able to identify where the engine came from those 2 things. Most of the 455s ran 2” intake valves, 375hp tornado ran 2” valves, the rare 1969 400 hp w-34, w33 police 455 and the hurst Olds ran the 2.07s.. Everything else was small valve. Odds are c heads are small valve, the but the bigger hp engine runs c’s with the big valves though.

We installed a Olds 455 from a 70 375 hp tornado in a 71 Chevelle back in 1993, it is still in the car. Had hardened seats and 2.07 valves installed and did a cam change at the time. Other than rings and bearings it was all stock. We painted the 455 Chevy orange. I have had the hood open a the drag races and people walk up then visit with me and just assume it is a sbc or a bbc. In the age of LS engines not many people will catch it is a Olds.

We have one C headed 455 engine in a McLaren M6b gt replica. All Olds 455’s had very similar head cc’s across the years (except for the rare w-30 F castings). Olds used a deeper dish in the pistons to lower the compression on later engines. If your engine was rebuilt, it is kind of hard to say what the compression is unless you know which pistons are in it.