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Old 11-16-2010, 10:56 AM
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1968 firebird

good morning everyone , i have the stock motor for this 68 but it has a spun bearing, i want to take the motor to get rebuilt but i dont know what size cam, lifters, pistons, or anything about Pontiac's. i would like to get 450+HP out of it . can someone help. thanks BET.

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Old 11-16-2010, 11:18 AM
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This a 400 engine or the 350? Either one is NOT the best for performance! "IF" performance is the major goal then you got two choices, keep it Pontiac and go with a 455 or a 389. OR get a Chevy engine (it's a bolt-up change & parts are alot easier to get and cheaper) Then get what you like SB or BB!
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Old 11-16-2010, 11:23 AM
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1968 firebird

yes this is a pontiac 400 ,i only want to keep it because it is a original motor for the car which makes it a matching numbers car. is there a was to make it happen
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Old 11-16-2010, 02:15 PM
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Quote:
Originally Posted by bigbet068
yes this is a pontiac 400 ,i only want to keep it because it is a original motor for the car which makes it a matching numbers car. is there a was to make it happen
The 400 Pontiac is a great engine! The 455 has more low end torque, which makes it better for the street, but with all the aftermarket parts out there now, you can make a 455 out of the 400. Not real cheap, but it can be done at a reasonable cost. As far as cams go, all of the big name cam manufacturers have cams for Pontiacs, but I would consult one of the Pontiac engine builders. http://www.jbp-pontiac.com/ http://www.krepower.com/ http://www.angelfire.com/fl4/pontiac.../about-us.html http://www.sdperformance.com/ A lot of replacement parts can be found here: http://www.performanceyears.com/ The PY tech forums is the largest Pontiac specific forum out there. Give it a look.
11echo is incorrect about a Chevy being a bolt up change. The belhousing bolt pattern is different, the motor mounts are different, the starter is on the other side of the engine, and the exhaust manifolds don't interchange. Also, it would cost more to change over to a Chevy than rebuild the Pontiac and the Pontiac will have more power than any sbc.
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Old 11-16-2010, 02:48 PM
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1968 firebird

thanks for all the links would you know of a shop near LAX AIRPORT in los angels CA.
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Old 11-16-2010, 03:43 PM
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Ken at PPR http://www.pacificperformanceracing.com/about-us.html is, IMO, one of the better builders on the west coast. I do not recommend Rock and Roll Engineering, unless you like to gamble.
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Old 11-16-2010, 05:01 PM
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Quote:
Originally Posted by WDCreech
Ken at PPR http://www.pacificperformanceracing.com/about-us.html is, IMO, one of the better builders on the west coast. I do not recommend Rock and Roll Engineering, unless you like to gamble.
I red somewhere that a guy used 455 pistons (same size as 030 over 400 pistons ) and used a 455 crank in a 400 block by machining the crank down to 3 inch main journals . Effectivley making a 455 CI with of a 400 block.
His reasoning was something about 455 cylinder walls are thin and the metal removed from the main webbing area weakend them. IDK. Thought it was pretty cool to get 455 CI out of a 400.
BTW I just got a 65 389 for my Le Goat. ( ha ha). I am gonna freshen it up and slide a bumpstick in it, the 350 in there now will come out in the spring and I will be looking to do some mods to it as well. I will keep it for a backup... or maybe I will by another lemans.
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Old 11-16-2010, 07:54 PM
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Quote:
Originally Posted by latech
I red somewhere that a guy used 455 pistons (same size as 030 over 400 pistons ) and used a 455 crank in a 400 block by machining the crank down to 3 inch main journals. Effectivley making a 455 CI with of a 400 block.
To use a turned down 455 crank on a 400 (or 389) block, you need a thrust bearing spacer made by Ken Keefer of Ken's Speed and Machine.

His reasoning was something about 455 cylinder walls are thin and the metal removed from the main webbing area weakend them. IDK. What it actually does is reduces the amount of material between the main saddle and the cam journal, increasing the chance of splitting the block.

Thought it was pretty cool to get 455 CI out of a 400. BTW I just got a 65 389 for my Le Goat. ( ha ha). With all the aftermarket cranks out there, you could do a similar mod to the 389. You might have to get aftermarket pistons unless your block will go .090" and you have a set of later heads.

I am gonna freshen it up and slide a bumpstick in it, the 350 in there now will come out in the spring and I will be looking to do some mods to it as well. I will keep it for a backup... or maybe I will by another lemans.
If you look at Ken's (PPR) site, You will see that he has a stroker kit to make a 383 out of a 350, also.
There are lots of choices out there, so plan wisely, and good luck!

Bill
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Old 11-17-2010, 06:53 AM
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Quote:
Originally Posted by bigbet068
thanks for all the links would you know of a shop near LAX AIRPORT in los angels CA.
Do yourself a favor by reading all you can on the in's and out's of the Pontiac engine. They're NOT a Chebby- and shouldn't be built the same as you would a Chev.

Links?? lol

SOME SITES FOR PONTIAC PARTS & INFO:

Butler Performance- http://www.jbp-pontiac.com/

Ken’s Speed & Machine Shop- http://www.angelfire.com/fl4/pontiac...chineshop.html

Nunzi- http://www.nunzi-pontiac-expert.com/

Fulper* aka Rock & Roll Engineering- http://pontiacpower.com/
*One of the Pontiac guys here has warned, “…in the better Pontiac circles, Bruce Fulper (Rock & Roll Engineering) is a bad word. He has screwed too many people and he is a pathalogical liar!” More, beginning at Post #32.

SD Performance- http://www.sdperformance.com/

Kauffman Racing Equipment- http://www.krepower.com/

All Pontiac.com- http://www.allpontiac.com/

Wallace Racing- http://www.wallaceracing.com/


A FEW ARTICLES BY JIM HAND (there are many more)

Jim Hand “BUILDING A STRONG STREET MACHINE”@ Classic Firebird
http://www.classicfirebird.com/hand/hand.html

Hand on Cams
http://www.dapa.org/jhpages/pontiac-cams.htm’

Hand on ROCKER RATIOS/MODS
http://www.pontiacstreetperformance....ockerArms.html


PONTIAC MAGS ON THE WEB:

Pontiac Street Performance
http://www.pontiacstreetperformance.com/

Pontiac Street Performance Featured Cars & Engines
http://www.pontiacstreetperformance....turedcars.html

Pontiac Street Performance Tech Articles
http://www.pontiacstreetperformance....harticles.html

High Performance Pontiac
http://www.highperformancepontiac.com/

Also, there have been numerous threads on Pontiac engines here at Hotrodders- hit the "Search" for more info.

Good luck.
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Old 11-17-2010, 03:32 PM
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Hey lets state some facts on the 400, from 1976 to 1979 400 blocks (some, not all) came with VERY thin castings. It was a factory "better idea" to save money by reducing the mass of the block castings. They thinned down the cylinder walls and the engine main webs, they are known to fail in any application over 400 horsepower! The "557" blocks are weak & the 500557 and 568557 blocks are to be avoided! Also another weakness is the open lifter valley which can be cracked by using solid roller cams w/ heavy spring pressures and no lifter brace.

Quote:
WDCreech ..."11echo is incorrect about a Chevy being a bolt up change."
OH MAN! ...You got me! I admit it, you can't bolt up Chevy heads on a Pontiac engine! ...OR exhaust manifolds, or intake manifolds. BUT your wrong about starters ...I personally took a 59 Chevy starter and bolted it to my 65 GTO (after I swapped the nose off my old starter! )

Look, you want to be nostalgic and keep it all Pontiac I say go for it! More power to you! You can make a very nice street monster, But if you want ground shaking performance and your NOT made of money, then look at BOTH Chevy parts vs Pontiac parts cost then make your own decision ...That's all I'm saying, Good Luck!
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Old 11-17-2010, 06:21 PM
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Quote:
Originally Posted by 11echo
Hey lets state some facts on the 400, from 1976 to 1979 400 blocks (some, not all) came with VERY thin castings. It was a factory "better idea" to save money by reducing the mass of the block castings. They thinned down the cylinder walls and the engine main webs, they are known to fail in any application over 400 horsepower! The "557" blocks are weak & the 500557 and 568557 blocks are to be avoided! Also another weakness is the open lifter valley which can be cracked by using solid roller cams w/ heavy spring pressures and no lifter brace.

OH MAN! ...You got me! I admit it, you can't bolt up Chevy heads on a Pontiac engine! ...OR exhaust manifolds, or intake manifolds. BUT your wrong about starters ...I personally took a 59 Chevy starter and bolted it to my 65 GTO (after I swapped the nose off my old starter! )

Look, you want to be nostalgic and keep it all Pontiac I say go for it! More power to you! You can make a very nice street monster, But if you want ground shaking performance and your NOT made of money, then look at BOTH Chevy parts vs Pontiac parts cost then make your own decision ...That's all I'm saying, Good Luck!
__________________________________________________ _______________

Where do I start? The 557 block (late year 1975 to ?) were thin in the main webbing, not cylinder walls. They went back to a thicker casting, I believe, in '77. I agree tat the 557 blocks should be avoided unless you are building a bone stock grocery getter. The open lifter valley is another problem if you are planning on over about 750 HP. I had a 455 block start to split at about 740 horsepower. I had a lifter bore brace, so I didn't have lifter problems.

That starter wasn't a bolt up deal, it was a rebuild and bolt up! Have you ever bolted a Chevy engine to a Pontiac automatic transmission? It ain't going to happen unless you use an adapter.

If you want to be like everone else, put a Chevy in it. It won't save you any money if you already have a Pontiac, but what the hey? Everyone will tell you it would be faster with a Chevy. I like to ask them to compare time slips with me. That's when they start back peddling.

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Old 11-17-2010, 09:51 PM
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I have to say, these guys are right, I recently built a 455 and its a pretty much stock motor and it is QUICK!

check out there links and listen to there advice! they know whats up

and IMO i would stay pontiac, creech is right you will spend more money trying to get all of the chevy stuff to mount up correctly and getting all the little stupid things right. just build yourself a fun engine and slap it back in without having to worry about changing mounts, trannys, etc.
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Old 11-18-2010, 09:10 AM
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Quote:
Originally Posted by 11echo
Hey lets state some facts on the 400, from 1976 to 1979 400 blocks (some, not all) came with VERY thin castings. It was a factory "better idea" to save money by reducing the mass of the block castings. They thinned down the cylinder walls and the engine main webs, they are known to fail in any application over 400 horsepower! The "557" blocks are weak & the 500557 and 568557 blocks are to be avoided!
The reply below is by “Rick” of the tech staff on Hitman's Pontiac Trans Am Forum. The entire thread is HERE.

Q. This all seems to be confusing me. The w72 blocks used in 78-79 were a reintroduced 988 casting but many say not to build later blocks due to their weakness. Can anyone clear me up on this? Did these blocks avoid the whole weight savings program?

A. I don't know who gave you the information, but either they don't know enough or they didn't tell you enough. Like most enduring myths, there is a grain of truth to what you've been told. But the picture is totally different once you hear "the rest of the story".

The original casting number for the early 400 CID Pontiac blocks was the 481988 number John mentioned above. It is a very strong casting and it has been successfully used for many high-power and stroker builds without any block problems at all.

The engineers in the drive train division looked at their engines, and decided that they could shave a few pounds out of the 400 block by redesigning it with thinner internal webs. The result of this was the 500557 block. It IS weaker than the 481988 block, but it's plenty strong for most street applications. In particular, it was WAY stronger than the factory needed for the 185 HP engine they were putting out in 75-76.

So... during the 1975 model year, Pontiac switched to the 500557 casting. They stuck with it through the end of the 76 model year. But as car production moved into the 77 model year, the painful memories of the gas lines of early 1974 faded. Pontiac had a few production problems with assembly of the 500557 block engines, and they wanted to emphasize performance a bit more with introduction of the higher-HP option package. Rather than sink the cost of engineering yet another revision to the 500557 block, they decided to simply revert to the 481988 block.

The use of the more robust block continued through the end of the Pontiac 400 CID engine production, during the 1978 model year. A set number of the 400 engines were stockpiled for the 79 model year, and then all the tooling was ditched because that was the end of the Pontiac 400, per corporate edict. The Olds 403 was use for the "big engine" production once the 400 engines were gone (all 400s were 4 speed, all 403s were autos), and for 1980 there were no more "big engines".

A 500557 block is fine for almost any streetable 400 engine you'd want to build, right up to 450-500 HP, and with RPMs under 5,000. It's not the BEST candidate for a stroker engine or a drag engine that's going to see 6,000+ RPM -- the 481988 block is much better for that. But given a choice, most people opt for the 481988 block if they can find one for the same or approximately the same money.

That's the entire ugly story... warts and all.
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Old 11-25-2010, 02:23 AM
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Bigbeto68 I don't know if you have started buying parts yet for your 400 build but the first thing I must recommend to any pontiac owner is to buy Jim Hands book how to build max performance pontiacs. There is a ton of great info you can use to choose the right components and plan your build. Doesn't matter the make but if you mismatch your components like cam, intake, heads etc your engine won't run right. It will show you the ins and outs of a pontiac and even has actual engine "recepies" in the back from various pontiac builders with time slips to prove their combo. It's always nice to have a matching numbers car and your power goal is very achievable. One thing to consider is a stroker kit. It is so common now for guys to build a 461 out of a 400 block. You're basically taking a 455 crank and putting it in the 400 block and boring/clearancing. The 400 block will be stronger and be able to spin alot more RPMs than a stock 455 block but you will gain the cubic inches and you can buy these kits forged and would be one heck of a sleeper! The book will explain all of this so get it and good luck with the build. Keep us posted.
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Old 11-25-2010, 09:16 AM
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I'm new to this kind of stuff. How much will it cost to get 450hp out of a Pontiac.
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