Will it fit????

Hey everyone,

I had basically posted the same thing in the Oldsmobile forums, but this is of equal concern to this forum, and I need to hit up the right person that knows their stuff about this, before I invest into the motor I have.

Anyway, here's the low-down. My current project car is a 67 Pontiac FireChicken. She has a 326 in her currently (yes, a 326). Anyway, I have been looking to get a hold of a Pontiac 455 to stuff into her, specially since it would bolt right in. Anyway, this past weekend, while up in the Finger Lakes for the 4th of July, I stumbled across someone selling a complete 455 motor. I was a bit wary when getting it, that it in fact might be an Olds 455 not Pontiac, but being that the motor was a STEAL it took her home, and she now sits in my garage. Anyway, she is an Olds 455 (396021Fa), which after some research tells me, that she is a pretty common 455 block, but pretty excellent for building some horsepower with. I have run into, and heard good things about Mondello, so I think I will go with them, for at least heads, but my biggest concern is this. Will an Oldsmobile 455 fit into a 67 FireChicken/Camaro?? I imagine that there's not much difference between it, and the Pontiac 455?? My 2nd question is, will it bolt up to an old PowerGlide tranny?? I have a 2 speed PowerGlide in the 'Bird right now, and I'd like to keep it, as old PowerGlide's can handle some serious power, and the 2 speed currently shifts out of 1st gear at about 60mph!!

Any help anybody has would be greatly appreciated....THANKS!!

Badbird, let's clear up a couple of misconceptions. First, there is virtually no similarity between an Olds 455, a Buick OR Pontic 455. All three are as different as night and day, with the only exception being the bellhousing flange. They all bolt up to the "BOP" (unChevy) pattern.
The Olds will physically fit in the engine bay. The mounts are completely different. The width of the big Olds makes for an adventure in exhaust systems. Headers would have to be "custom" made.
The transmission in your car is a "Super Turbine 300", not a Powerglide. Powerglide is pretty much exclusive to Chevy or cars with Chevy engines (some 6-cylinder Pontiacs had them). There are no interchangeable parts, and the ST-300 is not a good candidate for performance.
While the Olds can be made to perform well, in relatively stock form, it won't touch the Pontiac. If you spend the same dollars on each engine, the Pontiac gets further ahead. Contrary to popular belief, Pontiac engines (unlike the Olds and Buick) do not fall into the "point prover" or "also ran" classes. The Pontiac can be made to be a serious contender, even with high-end big block Chevy. A trip to the TriPower Nats will adequately illustrate that, with MANY "door cars" solidly in the 7 sec. 1/4. Long cars are in the 6s, too.
A far easier, less expensive and nearly as effective approach would be the Pontiac 400. It will bolt right in, make well over 400 horsepower for reasonable money, and won't get you shunned at the local car shows where the cool Pontiacs show up. The quickest way to be on the outside looking in, is to put a non-Pontiac engine in your vintage Pontiac.

Well, it's great to finally talk to somebody "in the know'!! Thanks for all your input. You are unfortunately confirming my nightmares about this motor. Truth be told, I was originally looking at buying an honest to goodness Pontiac 455 from a friend I used to work with before I moved to Pittsburgh from Buffalo, but lately has been doing the "not returning my calls thing". When I went up to our cottage this past weekend for the 4th, when a buddy of mine said they were getting rid of a 455 motor, I kind of lept before I looked. Mostly because the engine was a steal and a half, I was 6hrs from home, and had no internet connection to check up on it. I had my suspicions when I bought it that it might be an Olds 455, but again, for the above reasons, and moreover it being a complete motor, and cheap, I decided to give her a good home. Once I did get home, and ran the casting# I found it to in fact be an Olds 455. So suddenly everything in my mind changed to..."how can I make this work?", "how different are Olds, Buick, and Pontiac". I did know that a Pontiac block will yield more power, but being that an Olds also has a lot of power potential, it still made it attractive to me. My 'Bird is going to be a ton of work as it is, I kind of don't want to have to fabricate my way into dropping a motor into that car. I think I may try and sell the Olds 455 or find me another donor car for it to be happy in. It's just so hard to let go of a perfectly good Big Block!!

Here's a question for you though. What about the 326 that's in my 'Bird right now. I've not had the car for more than 3 months, so I'm still learning everything I can about her...so forgive me. I think I remember reading, or somebody telling me that the 326 is really a 400 block but is shorter stroke x smaller bore. Is this correct?? If it is, how much sense would it be for me to pull the 326 and bore and stroke it to a true 400?? I must say, when I got her, she didn't run at all, and now, that 326 run PERFECT, definitely still a good motor, would almost be a shame to let it go by the wayside if you ask me.

Thanks for correcting me on the tranny. I was told when I bought it that it was a PowerGlide, I think he said the tranny was swapped now that I think about it....so it may really in fact be a PowerGlide...but I should really take down the numbers off it, to be sure.

Anyway, let me know what you think, and thanks again!

I think you should find a 442 or Cutlass to put that motor into...

Well, there was a 71-72 Cutlass that was for sale around the corner from my house.....if I buy it, I'll be up to 6 cars, but maybe he might want a 455 for it!!

Well, it's great to finally talk to somebody "in the know'!! Thanks for all your input. You are unfortunately confirming my nightmares about this motor. Truth be told, I was originally looking at buying an honest to goodness Pontiac 455 from a friend I used to work with before I moved to Pittsburgh from Buffalo, but lately has been doing the "not returning my calls thing". When I went up to our cottage this past weekend for the 4th, when a buddy of mine said they were getting rid of a 455 motor, I kind of lept before I looked. Mostly because the engine was a steal and a half, I was 6hrs from home, and had no internet connection to check up on it. I had my suspicions when I bought it that it might be an Olds 455, but again, for the above reasons, and moreover it being a complete motor, and cheap, I decided to give her a good home. Once I did get home, and ran the casting# I found it to in fact be an Olds 455. So suddenly everything in my mind changed to..."how can I make this work?", "how different are Olds, Buick, and Pontiac". I did know that a Pontiac block will yield more power, but being that an Olds also has a lot of power potential, it still made it attractive to me. My 'Bird is going to be a ton of work as it is, I kind of don't want to have to fabricate my way into dropping a motor into that car. I think I may try and sell the Olds 455 or find me another donor car for it to be happy in. It's just so hard to let go of a perfectly good Big Block!!

Here's a question for you though. What about the 326 that's in my 'Bird right now. I've not had the car for more than 3 months, so I'm still learning everything I can about her...so forgive me. I think I remember reading, or somebody telling me that the 326 is really a 400 block but is shorter stroke x smaller bore. Is this correct?? If it is, how much sense would it be for me to pull the 326 and bore and stroke it to a true 400?? I must say, when I got her, she didn't run at all, and now, that 326 run PERFECT, definitely still a good motor, would almost be a shame to let it go by the wayside if you ask me.

Thanks for correcting me on the tranny. I was told when I bought it that it was a PowerGlide, I think he said the tranny was swapped now that I think about it....so it may really in fact be a PowerGlide...but I should really take down the numbers off it, to be sure.

Anyway, let me know what you think, and thanks again!

Just a few comments here. Yes the 326 is a Pontiac block, so externally its the same as a 389-400-455. The stroke is the same as the 400 at 3.75", but the bore is smaller at 3.71" The 400 has a 4.12 bore.
The 326 was last made in 1967, so it's quite rare. For Firebirds, this was a one year only combination, so would be a shame to change it. If you do change it, keep the original engine.
It was the first step up from the 6 cyl, so it's not really a high performance engine.
I agree with MrPbody for the most part. However, the Olds engines had as much performance potential as a Pontiac. Their only mild weak point is that they are a relatively long stroke engine, (with slightly smaller valve ports) so they build excellent low and mid range power, (good for a heavier car) but they don't really build revs too quickly.

The 400 is a relatively short stroke engine, so it builds revs faster, and good big valve cylinder heads are easy to come by. This is better for a lighter car like yours. That being said though, beware, virtually all Pontiac v8's came with cast connecting rods, (except for some really rare 421's and 'super duty' 455's) not forged, like almost every other american made V8. Therefore, the engine can't build high revs too much or the rods come out the bottom. You can get forged rods but they cost a lot. Performane parts are more easily found for Pontiac engines than for Olds and Buick motors.

The most important thing, though is to keep your car all Pontiac. That will enhance its value, its interest and make for much easier parts swapping.
I would suggest locate a Pontiac 400. They are more common than the 455's and for a lighter car, can be built to go as fast or faster than a 455, because of their ability to rev well.

As for the transmission, the Powerglide are better than anything else, in lighter cars (weighing less than 3000 lbs) when properly built for drag racing. However, if you are going to use it for the street, with a taller rear axle ratio, say 3.23:1 or lower, consider a THM 400 (or 350, if you are not building huge power). It will give you better performance than a Slip'n'Slide, all other things being equal.

Exactly how rare is the 326?? I mean how much money is it worth? The motor runs strong as hell, even more reliable than my 2 yr old Nissan for that matter. Any idea how many 326's were put out? It is kind of attractive that the 326 is a bit rare, and I have a 1st year Firebird, but at the same time, boring out that motor, changing up the internals, different heads, intake, cam, and ignition is pretty attractive to me, and also even though it'd be all overhauled, it would still be the original, numbers matching motor pounding away under the hood. My intent with the 'Bird was never to restore it, but to make it into quite the terror on the Street. 400+ hp, updated suspension, impressive interior.....blah blah blah.

Badbird, The 326 is NOT in collector demand. While the cars are a bit on the "rare" side, not every old car is more valuable just because it's "rare". The 400 cars, while outmubering the 326 cars by nearly 2 to 1, are worth MUCH more money.
The Olds 455 has virtually the same bore and stroke of the 455 Pontiac. (4.125 x 4.25 vs. 4.155 x 4.21). The real difference in performance comes from what MR said, the heads. Pontiac heads are far superior in design, especially for a street performance engine.
The 400 Pontiac is probably the second most popular muscle car engine of the entire era, second only to BBC. This assumes, of course, you don't consider the little motors as muscle. 350 Chevy would be no. 2, and 400 third. There were quite literally, millions made. Much easier to find today than a 455, and a lower cost.
Forged rods for Pontiac are readily available and not as high as you might think. We also do a significant amount of bottom end enhancements these days, unheard of except among the die-hard Pontiac racers, until recently, with the massive resurgance of Pontiac power popularity.
There are blocks, heads, cranks, rods, etc., from several different manufacturers, driving prices down on many previously cost-prohibitive parts. It doesn't cost any more money today, to build a 600 horsepower Pontiac than it does to build a 600 horsepower BBC, and it will make 10% more low-end torque.
Jim hand of Kansas City, has just released a new book on how to build Pontiacs. "How to Build a Max-Performance Pontiac V8". It's the first comprehensive study of the Pontiac V8 since the HO Racing book of the mid-'70s. There are a couple other books regarding performance, but they're aimed at a particular class, as with Pete McCarthy's "Pontiac Racer's Handbook", which details the preparation of an NHRA legal Super Stock engine (now obsolete due to rule changes in S/S).
I spoke to the publisher last week. They've nearly sold out the first printing before the release date. The ONLY other book Car Tech has sold that quickly was the new one for the 4.6 Ford, a current "performance" engine. They are amazed at the market. Edelbrock was, too, when they released the heads, and again when they released "Victor" (currently, the best single carb intake available for Pontiac). Yup, Pontiacs are back, and with a vengence!

I also have a 67 firebird I just purchased. It has the 400 out of a GTO in it with a 3.08 rear gears. It will pull 13's in the 1/4. And gets 20mpg on the interstate. Not bad for being in the mountains of Utah. I personally like the 400 set up.

I ran a 67 bird with a 671 dyno'ed horse power in the 70's . The bearings never held up , I spun mains and rods several times with 3n different blocks. I have a detuned 455 in my 68 bird using the ported ramair 4 heads 1050 dominater on an edlbrock 180 degree manifold from that engine. Have the pontiacs rods and blocks improved enough to stay alive very long with 600HP.

Very interesting thread - I just joined & this is the first thread I've viewed.

I currently run a Pontiac 400 in the Dirt Super Late Model division here in the NE - the only Pontiac powered car no matter where I go. Over the years, have run just about every Pontiac mill produced except the 1958. Even got a 2nd place finish with a 326 in a Dirt Super Stock back in the 70's.

An earlier post implied spun bearings plague these engines. Well, I've never spun one in a Pontiac during 1000's of high RPM laps. I did; however, have a 389 (w/030 overbore) come apart explosively back when I was sponsored by Pontiac - they insisted on building the engines as their "name" was at stake. Turned out their engine/machine shop made several tolerance errors on the crank & piston work. I've built my own ever since.

I have lost other manufacturers engines tho due to fusing crank & bearing, namely a Ford 312, Plymouth ('57 engine) 301 & Chevy 409.

From my personal experience, I would tell the fellow with the 326 in a 67 Firebird that he should be very satisfied; and, find it enjoyable employing that engine - most of Pontiac heads, intakes, internal parts are interchangeable and easily found. With every Pontiac engine rebuild, use at least the 60LB PSI oil pump. I ALWAYS use a 80LB PSI oil pump, either new or newly remanufactured. The 60LB PSI pump is certainly easier to find.

Pont287! Welcome aboard! You sound like you could be as old as me! Do you still have a '55?

Things have really changed in the Pontiac world over the past few years. Yes, they are making more than 600 horsepower on pump gas. Yes, they're living just fine.
Circle track racing will definitely test the "metal" of any engine. Good job! I'll bet it comes off the corner harder than any of those light-weight high revvers! I did some Pontiac circle track engine work a few years ago for a guy at Dixieland Speeday in Elizabeth City, NC. It finished 22 races, and broke in the 23rd (bad radii on crank, won't ever happen again...). It won 19 of the 22, and finished in the top 3 in the other 3. He spent 8 weeks in Equador during the season and still finished 2nd in points.
You should e-mail me direct. We need to talk. There's an entire Pontiac "underground", if you're not in it, you should be!

Jim ([email protected])

No Jim,

I don't have a '55; but, do have the old style water pump that shoots water into the front of each head. The first dirt car I got into was a Pontiac 287 powered modified at Chemung Speedrome in 1958 - made a fool of myself and embarrassed my father who was in the pits watching in horror. But, you gotta start somewhere.

As far as the age, I'm no youngster for sure - competed in the Chili 100 two weeks ago at Ace High Speedway and was the oldest guy on the track. I had never raced at that facility before and the track condition was terrible, rougher than anything I'd seen in years, had all the power I needed; but, my setup/suspension was no match for the surface.

Since it was a Super Late Model event, we had to run against several aluminum block machines & they pretty much out-classed the rest of the field with one exception - a steel block Chevy driven by last years Chili 100 winner and former track champion came in 3rd.

I jotted down your e-mail address & will send you a note. Felt I better answer here initially in case someone else was wondering about the '55 engine & my old-timer status.

Take care,

Stu