[ZnbOlds455]

I guess I'm going to start a build thread. I'm a rookie to this - both the documenting and the work. I'm working on a 1965 GTO I basically inherited from my dad. As stated in my intro thread in the Lobby, the body work is complete and it came with an Oldsmobile 455 that was rebuilt and seems to still be in great shape. The body will need some touch-up. The motor has some strange Superman theme with red and blue all over it. All that will slowly get cleaned up.

Here are some photos of the beginning of my journey with her.

[Scott Stoneburg]

Nice looking '65. Odd choice for power, but it must have been available at the time and better than a Chevy..lol.. Whats your plans?

[ZnbOlds455]

In the year since she came here, I've mostly been doing research and homework. My initial plan was to work on one subsystem at a time - i.e. fuel system, wiring, engine, trans, etc... My father-in-law, who was instrumental in the body work and engine rebuild done in 2008, has come over a couple times and takes a more ADHD approach.

I've installed fuel lines, swapped out the Oldsmobile stock iron intake with an Edelbrock Performer, installed trunk and door weather stipping, and ordered a bunch of parts. Since it's already a mash-up of parts, I'm going for a mild resto-mod.

I plan to work inside the car for a little while now. I've received the Vintage Air evaporator kit, a bunch of Dynamat, and a Dakota Digital HDX gauge cluster. I took the front end apart the other week since the doors were interfering with the fenders and so it'll be easier to work on the motor and A/C. The steering column has been cleaned and painted. The plastic dash was also cleaned and painted.

Here are some pics of how she sits now and what's next. Some of this is duplicated in my intro thread. Sorry about that, but I'll try to post here mostly now.

[ZnbOlds455]

This weekend's plans - Dynamat and start the dash.

[65 421 TODD]

ZnbOlds455, PM sent

[Jerry H.]

First thing I would do, regardless of where you go resto mod or stock, is to pull that Olds engine and find a Pontiac to go back in. I'm sure you could find someone who wants an Olds engine to recoup some of the costs of a good Pontiac engine. Believe me, you'll be better satisfied. At the least you won't have to listen to all the derogatory comments when you raise the hood.

[ZnbOlds455]

I figured the Olds would be a lower cost to get the car on the road. Ultimately, I hope to install an LS3 or so with the Pontiac dressing from a late model GTO or G8. I’m just playing the hand I was dealt for now.

[steve25]

I will be a nice car when it's done even with the Olds motor!

I know your not driving it yet, but please note that the small air cleaner on the Carb is a massive restriction!

Those Olds heads unfortunately have terrible Exh ports even for a 403 motor, no less a 455 even in stock form!

Since you say it's been rebuilt for greater performance if it does not have headers on it now if you where inclined to I would add such to that 455.

[RocktimusPryme]

I feel the same as others about the Olds motor. If you wanted to go with cheaper than a Pontiac I would go with a BBC. Cheaper and faster, instead of more expensive and a boat anchor. But really, if you ultimately want LS3 power, I would slap in a truck 5.3 now. Cheaper, and should have the legwork done for your dream powerplant.

My biggest advice is to not fall into the "perfect restoration" sinkhole. Get it running and driving asap. You can do the details along the way, but get it in a state where you can enjoy it as quickly as you can.

[steve25]

It's not just slapping in a LS3 now is it , as you make it sound all too easy as there's the big added cost of a trans swap and the correct lenght drive shaft to deal with also!

[RocktimusPryme]

Originally Posted by steve25

It's not just slapping in a LS3 now is it , as you make it sound all too easy as there's the big added cost of a trans swap and the correct lenght drive shaft to deal with also!

I agree, people always make swaps sound easier than they are. That said, its as documented/supported a swap as there ever has been. And you can stick with a vintage transmission with an adapter if you want to make it easier.

No matter what if you get it all ready to run with the vintage stuff and then later decide to go Gen III+ you are spending money/doing work twice.

If it was already a running and driving car, I would feel differently.

Does a big block olds maintain the same dimensions as a Pontiac? Is the transmission crossmemeber going to live in the stock place with the Olds 455?

[Cliff R]

If the big 455 Olds is running well I'd use it until it develops any issue that requires replacing it. They aren't too bad, sort of like a Pontiac 455, long stroke and not overly fond of high RPM's, but make great power (torque) in the mid-range. Most of the Old's heads don't have great combustion chambers and used dished pistons in them so love timing and can be prone to running hot, overheating, and detonation if you try to push the limits with them on pump gas. I've built quite a few here over the years, with decent results, but one would NEVER be on my list of engines to re-power one of these vehicles. Matter of fact just helped a local long time customer complete a 425 build to replace a 350 we helped him with about 10 years ago. He should have it up and running this weekend. I like the 425's, factory forged cranks in them, forged rods and good bore to stroke and rod length to stroke ratios. Downsides are the block angle and fitting them into later vehicles without jumping thru some hoops.........Cliff

[ZnbOlds455]

This Olds has the "C" heads, if that means anything. I don't know exactly what's in it, but I'm told it was built to run on pump gas. I may or may not put headers on it. There's not a lot of room between the heads and the frame.

The car was running reasonably well in 1985 with this exact motor and transmission. It just sat for 33 years when my dad took the car apart to do a complete restoration. His original plan was to do a complete restoration with a 389. That never materialized. In the meantime, my FIL rebuilt the 455 for another project but ended up scrapping the project and dropping the 455 back in the GTO for my dad. Then it sat for another 11 years until I grabbed the car in 2019. I've pulled that small air cleaner and swapped in a Performer intake for the Quadrajet carb.

I'm building a driver and trying to have fun and learn along the way. I'll stick with the Olds for now and use it as a learning experience. It fits fine and I know it was "running when parked". This may cost me more in the long run, but I'm OK with that.

[Jay S]

It is pretty easy to swap a Pontiac and a Olds back and forth. Starter is on the same side, radiator is the same, transmission bolts right up and locate the engine mounts perfectly on the crossmember when paired with the right bodies. Buick, Chevy and LS have the starter on the opposite side. Olds to Pontiac most of the wiring even hooks up. The little things add up on the LS swap. Pretty difficult to not like a 65 with any type engine swap. I love to see dual quad 421s in them.

In my immediate family we have 5 olds 455 cars. I am not afraid of them at all. Run it and have fun. Building a 500 hp is 455 a piece of cake. Turning them past 5000 the only unusual mod you really need is the oil restrictors that keep the bottom end oiled. Some of the early 455s can be bore .125” over. After 500 hp you add a main girdle and head studs. With some work porting the intake ports can flow up in the 300 range, the exhaust have a sharp short side and the floor is to low, it takes some work to correct that. Supposedly in stock form the early c, d, e, and f heads flowed around 250 (see the attachment). The E 1970 heads in our Chevelle 455 started around 225 cfm on our flow bench. I ended up around 265 cfm and 180 on the exhaust after I ported those heads. The E and the C are similar heads, we have one C headed engine.

My Dad gave my brother and I a 70 455 Olds for Christmas back in 1990, I was a junior in high school. A couple years later we stuffed it in our 71 Chevelle. We had big valves and hardened seat installed, arp rod bolts, high volume oil pump, new rings on the oem pistons, and a 214/224 .472 /.496 lift 112 lsa cam and headers with a q jet. It ran a best time of 13.67 @ 100 first time at track set up like that. A friend brought his 70 RA3 Judge to the track the same night and ran mid 14s. The fastest time of the night for the Chevelle was with my friend that had the Judge driving it. We all had a blast running the chevelle round robbin.

Porting the heads made a night and day difference on our Olds. You can see comparing the intake and exhaust flow files the E/I ratio is pretty low.

[Chris65LeMans]

Originally Posted by Cliff R

If the big 455 Olds is running well I'd use it until it develops any issue that requires replacing it.

I agree. I'm from more of the "if it ain't broke," camp. Plus, you've probably got plenty of other work to do.

Personally, I prefer it to a Chevy BBC, small block or LS.

As for the folks at shows - only Pontiac or Olds (not too many of them around) guys will notice.

[RocktimusPryme]

Originally Posted by ZnbOlds455

I'm building a driver and trying to have fun and learn along the way. I'll stick with the Olds for now and use it as a learning experience. It fits fine and I know it was "running when parked". This may cost me more in the long run, but I'm OK with that.

So it moves under its own power now? Like has a transmission and a driveshaft in it?

When you said it had an Olds 455 sitting in it, I assumed you just meant there was a motor sitting in it.

If you can fire it up and all without doing anything but basic maintenance to the drivetrain, I reverse my position. Leave it there, as that's the fastest route to being able to drive it.


I would just set mindful of letting it get over like 4500 RPM lol.

[Skip Fix]

I know my high school /college friend's jet boat hauled ass with an Olds 455 in it. It's there I'd use it.

[i82much]

Hey man, look. Back in the day, 80's and 90's, lots of guys were running around with Frankenstein creations, Old engine in a Pontiac, Chevy engine in a Cadillac, Pontiac engine in a GMC ... ok actually GMC did that from the factory :-) Anyway, personally I think it would be pretty cool to see a 65 goat running around with an Olds engine in it, nothing wrong with that. Have fun, get it running, make it how you want it later. Besides, you'll probably find you are constantly changing your mind about what you want out of the car anyway!

[ZnbOlds455]

I’m just doing the car for me. I really don’t care about shows. I’ll take my dad for rides, but that’s about it.

The car ran fine in 1985. It had some serious rust issues, but I don’t recall the extent. I was 11 and totally uninterested. Then my dad totally disassembled the car.

The motor was rebuilt and put in a 1973 Saab Sonnet around 2008. It ran, but my FIL abandoned the project. The 455 now sits in the GTO with a TH400 transmission that was rebuilt with the 455. I have the fuel lines run, but no drive shaft or wiring.

My plan is to start the dash and wiring this weekend so I can get the engine fired up. That will take a few weeks as I have many other responsibilities. I appreciate the words of encouragement. I’ve never attempted anything like this. I have no problems being a shade tree mechanic, limited to pulling, cleaning, and replacing parts. This GTO is all new territory for me.

[ZnbOlds455]

Well, I got the dash cleaned and sanded. It's ready for paint now. No local shop has anything decent for chrome paint, so I ordered some Spaz Stix.

I discovered that Dynamat's website is misleading. Their Dynaliner doesn't have a foil lining, making it nothing more than insulation. The website implied it was good for firewalls and floors. What they don't tell you is it's good for that AFTER applying their Dynamat Xtreme first.

I also discovered a flex plate dust cover that perfectly fits an Olds 455 w/ TH400 is unobtanium. I've tried 3 different ones that either had the starter on the wrong side - even though they said it would fit - or the holes wouldn't line up. I ended up with a plastic universal that was no better. At least it was easy to modify to fit.

Rookie mistakes. Live and learn.