[PunchT37]

Originally Posted by 65gto69

How about engine rotation.

Pontiac rotates opposite of a chevy, so when putting those spark plug wires on make sure you go counter-clockwise around the distributor or you will have real headaches like Barry White had on his TV show "Wrecks To Riches". Quite an embarrassing moment for him in front of plenty of Pontiac viewers when he was building that GTO/Lemans.

Mark

Engine rotation or just distributor rotation?

[Tom Vaught]

Quote:

"You guys correct me if I'm wrong but simply put Pontiacs are torque engines. That's longer stroke and smaller bore then the other guys' engines of comparable cubes."

First off we need to make a few comments:

In the 60s, the average engine was SMALL. 302/350/318 etc. The Chebby big blocks were prinarily 396 or 402 cid engines. Mopars were 383 engines with a few 440 engines. The "race engines" were 427 chebby, 426 Hemi, and 427 Ford and were so few in volume that they should not be part of the discussion.

The stock 389 engines 4.0625" bore was larger than any stock 302/350 type Ford or Chebby engine bore. The 400 cid Pontiac with its 4.12" bore was basically the same as the Chebby 400 engine and the stroke was basically the same 3.75" as the Chebby 400.

The Pontiac 421 has a 4.093" bore vs a 4" stroke so the stroke was SMALLER vs the Bore. Same deal for the Pontiac 428 engine: (4.12" x 4"). ONLY THE PONTIAC 455 HAD A LARGER STROKE VS THE BORE. (4.151" bore vs 4.210" stroke).

So 99% of that tale was pure BS.

A 4" stoke engine with a 4.18" bore can rev to 7000+ easily with the right Valvetrain/ Camshaft parts and good pistons/rods. Pontiacs made great street engines because they were typically larger than the average other street engines at the time in cars (Ford and Chebby 302/350 and Chrysler 318 type engines).

The Olds 442 engines and Buick engines had the smaller stroke and later went to the same larger type strokes as the Pontiacs.

Tom Vaught

[PunchT37]

Originally Posted by MandevilleBird

In what ways? As Poncho guys, we all seem to insist that you can't use a chevy attitude when building a pontiac engine. I don't have knowledge or experiance to know why.

Whats the deal?

Because Pontiac engines are a tall deck, smallish bore, long rod, heavy bottom end engine with smallish intake ports as compared to a Chevy. Hell, even the 287 had a 10.24 deck height compared to the 9.8 for the BBC.
That being said, the engine will tend to run a certain way no matter the cubic inch or the parts used. That is, instant torque, wide torque band and relatively low rpm compared to Chevy. So, one would tune a Pontiac to take advantage of these attributes instead of trying to tune for high rpm horsepower like a Chevy.
So, camming, gearing, manifolding, stalling etc. needs to compliment what the strengths of the engine, not make it into a small block chevy that has low torque, and can and HAS to rev to get power.
If one builds a Pontiac engine to try to behave like a SBC, he won`t win too many races, or have an un-streetable car. The engine won`t last as well adding to the stigma that Pontiac engines are junk.
If one tunes it to it`s attributes, they will find an engine that is very strong and will last a long time even in hard useage.

[pro-tour79]

why would a Chevy win races by reving it and a Pontiac won't? and why would a Chevy be streetable and an Pontiac not? engines are nothing but air pumps, FACT is that the latest parts available to the Pontiac world IS making the Ponatiac behave more like a Chevy and this is why we are seeing higher performance out of the Pontiac camp.

[65gto69]

Originally Posted by PunchT37

Engine rotation or just distributor rotation?

My bad, but the Pontiac guys know what I am talking about.

Distributor Rotation is counter-clockwise.

Mark

[INJUNTOM]

Originally Posted by 65gto69

How about engine rotation.

Pontiac rotates opposite of a chevy, so when putting those spark plug wires on make sure you go counter-clockwise around the distributor or you will have real headaches like Barry White had on his TV show "Wrecks To Riches". Quite an embarrassing moment for him in front of plenty of Pontiac viewers when he was building that GTO/Lemans.

Mark

I bought a car due to this.

They thought it had a falt cam or burnt valve

[PunchT37]

Originally Posted by pro-tour79

why would a Chevy win races by reving it and a Pontiac won't? and why would a Chevy be streetable and an Pontiac not? engines are nothing but air pumps, FACT is that the latest parts available to the Pontiac world IS making the Ponatiac behave more like a Chevy and this is why we are seeing higher performance out of the Pontiac camp.

1; Because the average Pontiac guy running the average Pontiac engine will rev past the hp point and not use his torque. Running 4.56 gears and a 8" stall in the average Pontiac is counterproductive when all the average guy is turning 5200-5600. And turning most Pontiacs to 7000-7500 like most Chevies is gonna result in a broom and dustpan to pick up pieces.
Note, I said average. Modern parts are changing that to a degree.
2;

and why would a Chevy be streetable and an Pontiac not?

That`s not what I said. A Pontiac will ALWAYS be more streetable than a Chevy.
A Pontiac can run a taller gear with less stall in a heavier car and be more tolerable on the street than a Chevy. They use torque and not rpm to get the job done on the street.

3; I agree with you on the parts.

[Karfever]

Originally Posted by 65gto69

How about engine rotation.

Pontiac rotates opposite of a chevy, so when putting those spark plug wires on make sure you go counter-clockwise around the distributor or you will have real headaches like Barry White had on his TV show "Wrecks To Riches". Quite an embarrassing moment for him in front of plenty of Pontiac viewers when he was building that GTO/Lemans.

Mark

Oh yeah! I have done that mistake. My first Pontiac (65GTO) thought we would give it a tune up, after which it would not start/misfire etc. Could not figure it out, so it MUST be slipped timing, time to replace the cam and gearset. After all that, you guessed it, no start. I bet we adjusted the valves 20 times. I finally gave up and had it towed to the Pontiac dealer. (this was in 1972 when they actually worked on these cars). While I was waiting for the mechanic to come out and take a look, a salesman came up and was asking what the problem was, after I told him what the issue was, he said "you have the plug wires on wrong for a Pontiac'. WTF!!!! A quick change on the plug wires and it fired right up!

[guccieng]

Originally Posted by pro-tour79

why would a Chevy win races by reving it and a Pontiac won't? and why would a Chevy be streetable and an Pontiac not? engines are nothing but air pumps, FACT is that the latest parts available to the Pontiac world IS making the Ponatiac behave more like a Chevy and this is why we are seeing higher performance out of the Pontiac camp.

for the record, i respectfully disagree with everything you said. saying engines are nothing more than air pumps is like saying women are only here to make babies. the latest parts are making our pontiacs act more like a chevy how? and we're only now seeing a higher performance level? i've respected everything you've ever posted 'til now.

[71firebird400]

Originally Posted by guccieng

for the record, i respectfully disagree with everything you said. saying engines are nothing more than air pumps is like saying women are only here to make babies. the latest parts are making our pontiacs act more like a chevy how? and we're only now seeing a higher performance level? i've respected everything you've ever posted 'til now.

Well they are all air pumps, it doesn't know it's a Pontiac. I think the point pro-tour79 was trying to make is that there is no law saying all Poncho's are torque driven street engines that don't rev past 5K. Also, by saying they 'act more like a chevy'- I believe he's referring to the newer heads that are flowing more (Pontiac's have always been at a disadvantage, a lot of our 'ported' heads flow worse or equal to many off the shelf SBC heads), but now that we're getting better stuff we can have a 505 that can still breath at 7000 rpm.

There's a lot of stigma with a Pontiac amongst other car guys- I don't remember where I saw it but somebody once said; " I asked my engine builder what it would take to get 600HP out of a 455, he said '7000 RPM and a bucket to pick up all the pieces'"

[pro-tour79]

engines are nothing but air pumps, how can that be argued? it's fact!? the thing is that Pontiac engines were designed to be very efficient at low rpm but low rpms limit the amount of power that can be made because any time air flow is improved through the engine the torque band goes up in rpm in turn making more HP, remember that engines don't make horsepower, it is only calculated data from torque measurment (toque X RPM/5252= HP)

puncht37 quote
"If one builds a Pontiac engine to try to behave like a SBC, he won`t win too many races, or have an un-streetable car"


Well there are two negatives in this sentence but I thought you meant that if you build a Pontiac like a Chevy it would not win races and be un-streetable, am I incorrect?

But actualy the way it is writen it means that if a Pontiac is built like a Chevy it would not win races but it would be streetable
Fact is that if you put a big cam in a Pontiac or a Chevy and have poor idle, no vac... why would the Chevy be streetable and the Pontiac no be?,but since we are talking about average engines, average iron Pontiac heads flow the same or better than SBC iron heads so for a given CID the Pontiac should make power at higher rpm!

BTW you NEVER said "average" in post #23 to whitch I replied

71firebird is correct, new parts improve air flow in turn increassing the ability to rev and make more HP, ref. to HP formula above

[PONTIAC DUDE]

I've built & twisted a few of my Pontiac engines like a Chevy into the 7600 range. LOL. They loved it.

Now the wife's 8.5-1 455 liked 4800 rpm to run 12.90's. LOL.

But it's all in the combo and heads/intake.

[Thumpin455_GTO]

So while pro tour and the others are arguing, has anyone looked into the effects of a longer intake port and what it does to power output? Didnt the TPI on chevy engines in the 80s make more bottom end at the expense of top end power? Isnt the Pontiac a much taller deck engine than the sbc, and thus it wold have longer intake runners? I am referring to the entire length, from carb flange to valve.

For an extreme example take a gander at the cross ram Chrysler put on the B and RB engines. The carbs were on above the valve covers, or outside of them to get a longer runner. Those engines didnt spin to 8000 rpm easily either.

Its much more than just a flow number, or a valve size that makes engines behave differently. If they were all just simple air pumps, there would be absolutely no difference between them provided the valves were of similar size and the bore and stroke were similar. The closest apples to apples comparison you can get with the sbc and Pontiac is the 400, same bore and stroke, but with almost everything else being different. The sbc is a winder, much more so than the Pontiac. A good part of that is port length.

BTW, some of us have made 600hp under 6500 rpm. We dont need the rpm, but we can still use it. The application is more important to what powerband is utilized. Not everyone here wants to drive a 700hp 505 around, not everyone can afford it but they still want the GTO or Bird to move. Grunt engines move things easier with less gear, high rpm engines need more gear to move the same mass as quickly. So we tend to build tractor engines, because we tend to have street cars, not dedicated drag cars.

[Skip Fix]

Lynn our resident Super Stocker LOVES HP at the expense of TQ even. He has shifted a 455 at high rpm even using iron heads for years.

The airflow we try to use in most of our heads is what the "race" motors of 100ci smaller Chevy engines are using.

I think the Mr. P body quote says it all. And why there are more 11 second and faster Pontiac cars that are "streetable" than there were before we had all these aftermarket stuff.

[pro-tour79]

not arguing at all just pointing facts, and disputting myths about Pontiacs, and yes engines ARE air pumps, and air flow IS EVERYTHING, the key is how much and how efficiently that air flow is managed in order to produce power at the desired rpm
I'll start at the top.
Pontiacs engines were engineered to produce low end torque, this did two things, the ability to run high gear to provide good mileage, and reliability in a production vehicle.

600HP below 6500? that's about 500 torque that get's tough to do without CID, how big was the engine, any dyno sheet?

[Steve C.]

I built a 462 for street use with the specific goal of making 600 hp at or under 6000 rpm. It took a Victor intake to get the job done with 600.9 hp and 595.1 ft.lbs. torque on the dyno at exactly at 6000 rpm. It used 313 cfm 87cc E-s with 9.7 compression and 254 at .050 solid roller with a HP950 carb. But I ran the combo with a Performer RPM intake with a lower 5800 peak rpm to better match my tight 10-inch Continental converter, with that intake it made 589.1 ft.lbs. torque. Nothing exotic and lots of fun. On another website within a similar topic I was told this combo was not streetable and it was a dedicated race engine because of the high 5800 rpm. To each his own opinion but there are many who feel 5800 rpm or thereabouts does not tie a combo to a race category. To think that a Pontiac can't or shouldn't operate in that realm on the streets is absurd.

[pro-tour79]

there you go, that's what it takes to make that type of power but the isue is a Chevy would do the same thing given the same parameters

[PONTIAC DUDE]

Originally Posted by pro-tour79

not arguing at all just pointing facts, and disputting myths about Pontiacs, and yes engines ARE air pumps, and air flow IS EVERYTHING, the key is how much and how efficiently that air flow is managed in order to produce power at the desired rpm
I'll start at the top.
Pontiacs engines were engineered to produce low end torque, this did two things, the ability to run high gear to provide good mileage, and reliability in a production vehicle.

600HP below 6500? that's about 500 torque that get's tough to do without CID, how big was the engine, any dyno sheet?

I'm making 675hp at 6400 on 93 octane. Hydraulic roller. Yes CID. very streetable.

[Schurkey]

Originally Posted by pro-tour79

engines ARE air pumps, and air flow IS EVERYTHING,

NO. They are NOT "air pumps". Pumping air is PART--but not ALL--of what makes an engine produce power.

Air pumps do not have to EFFICIENTLY and QUICKLY BURN a fuel mixture. The piston(s) in an air pump are driven by the crankshaft. The crankshaft in an engine is driven by the piston(s).

So things like combustion chamber shape; piston top shape; and spark plug location can make a HUGE difference in how an engine makes power--and you might never know by looking at flow-bench statistics.

Fans of every GM division except Chevy want to jack up how wonderful their "favorite brand" is at low-end torque. I hear the same stuff at Olds, Buick, and Cadillac forums. Olds, Pontiac, and Cadillac folks brag up the long stroke = torque argument; Buick folks seem to have a better grasp on what makes torque (cubic inches and cylinder pressure) because they make low-end torque using a short stroke and huge bore.

You can take a Chevy and make low-end torque--God knows GM shoved enough 427s into dump trucks and school busses. For the most part, all you need are high-velocity ports and a mild cam.

Low-end torque is a function of CUBIC INCHES and INTAKE/EXHAUST VELOCITY; combined with the aforementioned combustion chamber efficiency. (or, put another way--engine size and cylinder pressure)

Any engine that can make high-rpm power can be detuned by changing the cam, heads, and manifolds to make low end torque--but not the other way around. (especially true for small-bore engines which are deprived of valve (and therefore port) area--until you go multi-valve or install power-adders.)

Does any of this invalidate the "Pontiac Philosophy"? No, not really. It DOES mean that if you want to make power higher up in the RPM band; you better bring some aftermarket heads to the party. (and, of course, a bottom-end strong enough to take the RPM) And what's news about that? Pretty much true for every engine I can think of.

[Thumpin455_GTO]

Originally Posted by pro-tour79

600HP below 6500? that's about 500 torque that get's tough to do without CID, how big was the engine, any dyno sheet?

Im not saying you are wrong, or that anyone else is. Just pointing something out that does have an effect, and its often overlooked.

467, 270/272 solid roller, 330 CNC 87cc E heads, Victor, 1050 on ethanol. Its a slight upgrade from Butlers EMC engine from a few years ago. (Butlers engine made 659hp@6200FWIW) When I get a chance to chassis dyno it again, I will post it up. Last time I did it made 522ftlbs at the rear wheels as it was blowing through the converter. Had not tuned it at that point either. It hasn't exactly been the most important project around here lately. Sure it will wind well over 6500, but it has plenty down low too. It will run no problem on 92 octane, I just like ethanol better, it helps that I make it.

Now that engine is quite different from the previous one in that car that had iron heads, stock rods, 228/230 hydraulic cam, and TRW slugs. It made 540 HP from 462 ci and enough torque to run 11s in a 3700lb Formula with a stock converter behind it. Let it do what it wants to do, not try to make it do something it doesn't want to do.

The second one is much more streetable, but the first one does pretty well considering it has a Dominator perched on it and it really needs a 4500 stall for best performance at the strip.

Also, PDude has made plenty of power, its not like its unheard of to have a 600hp Pontiac, or a 500ftlb Pontiac for that matter. Aftermarket parts have come a long way to helping our engines survive. Forged rods could just as well have been made of unobtainium when I built the iron engine 14 years ago. That was the main weak link for a street engine built on a budget. Now the 467 isnt exactly a budget engine is it? I have more sunk into that thing than any two of my cars.