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okay so i just bought a 76 pontiac 400 engine that i am aiming to build up for power that will eventually be put into my 72 lemans. now as far as thi motor i heard it is a slug but can be built up. i am looking to bore it .30 over, cam it, headers, edelbrock performer or air gap manifod, and i am just unsure of the ebst way to achieve my goal. please help me ith any information, tips, advice, or part suggestions thank you
 

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Locate and install some 1967-1970 cylinder heads that have factory screw-in rocker arm studs. They will have 2.11" I / 1.77" E valves and 72 CC combustion chambers for 10.5:1 CR. The problem with that is the "locate" part. All the good Pontiac heads been rebuilt to death. The best option is to purchase a new pair of Edelbrock 61599 aluminum heads. A 400 CI engine is difficult to make high HP on pump gas.

To make good power with a 400 CI Pontiac engine, it needs 10-12:1 compression ratio, a camshaft with .500" lift, 260 deg. duration and VP C-12, 108 octane racing fuel.
 

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Grumpy Old Goat Herder
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okay so i just bought a 76 pontiac 400 engine that i am aiming to build up for power that will eventually be put into my 72 lemans. now as far as thi motor i heard it is a slug but can be built up. i am looking to bore it .30 over, cam it, headers, edelbrock performer or air gap manifod, and i am just unsure of the ebst way to achieve my goal. please help me ith any information, tips, advice, or part suggestions thank you
The late model year '75 and all of '76 Pontiac blocks with casting #500557 are NOT a good choice for any kind of build up. As a cost saving measure, the factory cast them thin in the main webbing area and they are prone to breakage, especially when used in a build up application. Any other casting # 400 block is better suited to any kind of hopping up. The casting number can be found on the lip behind the passanger side head. See the attachement.
 

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Im running a 406 now it not hard to make power with them im bout 600 hp and I run 93 octane gas in mine the real problem is finding a good block most are not good went threw 3 to find one good one it is best just to buy a aftermarket dart block has better cooling and is a whole lot stronger block building a new engine and thats what I did by time u search have block tested and all the machine work done its not much more buy dart block mine was 1500 with freeze plugs and cam bearing install plus has splayed main caps with and is 4 bolt main
 

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okay so i just bought a 76 pontiac 400 engine that i am aiming to build up for power that will eventually be put into my 72 lemans. now as far as thi motor i heard it is a slug but can be built up. i am looking to bore it .30 over, cam it, headers, edelbrock performer or air gap manifod, and i am just unsure of the ebst way to achieve my goal. please help me ith any information, tips, advice, or part suggestions thank you
A lot depends on your budget.
A lot depends on the intended use of said engine
A lot depends on the car you will be puuting it in
Post the answer to the 3 questions, we can help you better that way.
There are plenty of unmolested pontiacs around for parts.At least where I live
 

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Pontiac 400 CI engine with 600 HP ?

My friend had a white 1967 Corvette L88 Convertible (1 of 20 made) and it was rated at 430 HP (GM actual dyno 560 HP) . It was formerly owned by the late TV music host Dick Clark.

Tell us more about a 600 HP Pontiac...I bet it is a daily driver too.
 

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Well dont know what mine was out of got block from junk yard and went from there my 406 is a daily driver I drive it when want to so what do u want know about it but nothing in my motor is factory if thats what u thinking scat crank scat rods je pistons afr heads solid lift cam victor intake holly 950 carb 1 7/8 headers msd ignition. My next one is going be stronger than this one but by no way did I say u were going buy a factory 400 with 600 hp if thats what u thinking but its not hard get power out the 400 if u want spend the money it takes to get it
 

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Well dont know what mine was out of got block from junk yard and went from there my 406 is a daily driver I drive it when want to so what do u want know about it but nothing in my motor is factory if thats what u thinking scat crank scat rods je pistons afr heads solid lift cam victor intake holly 950 carb 1 7/8 headers msd ignition. My next one is going be stronger than this one but by no way did I say u were going buy a factory 400 with 600 hp if thats what u thinking but its not hard get power out the 400 if u want spend the money it takes to get it
I think you're talking about a 400 Chevy. The OP was talking about a 400 Pontiac. AFR doesn't make Poncho heads AFAIK.
 

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Yea I dont deal with pontiac or olds or buick just figured it was bout same engine between the gm line I will have look into that more. So I guess disregard what I said bout my 400 as it dosent apply to you good thing I didnt get a pontiac 400 but really I just went after casting numbers that everybody said to use I think it was 509 casting and it was 2 bolt which I had converted to 4 bolt if pontiac is so bad wouldnt he be better just get a chevy or like I did for my new engine and get dart block
 

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Grumpy Old Goat Herder
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I've got 3 aftermarket Indian Adventures Pontiac blocks, one standard 10.23" deck and two at just over 11", and all have splayed billet mains. Chevies don't show me squat!

Bill

 

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WFO
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okay so i just bought a 76 pontiac 400 engine that i am aiming to build up for power that will eventually be put into my 72 lemans. now as far as thi motor i heard it is a slug but can be built up. i am looking to bore it .30 over, cam it, headers, edelbrock performer or air gap manifod, and i am just unsure of the ebst way to achieve my goal. please help me ith any information, tips, advice, or part suggestions thank you
A Pontiac 400 can be made into a very strong running engine. If you have the desire and money, you can put a 455 stroke crank into the 400 block (takes a crank w/400 sized main journals) for even more torque. Heed what was said above about which block to avoid if building a 400 into a "455".

But even at 406 ci (400 w/a 0.030" over bore), a Pontiac can shine. My way of building it would use basically a stock crank, forged rods, cast pistons, and casting 12, 13, 16, 62, 670, or similar heads or if the budget allowed, aluminum Edelbrock or KRE heads. An engine built w/these parts and a streetable cam could make an easy 450-500 hp and as much torque, w/enough vacuum for power brakes and an idle that wouldn't shake the fenders off the car.

Arm yourself w/info if you plan on getting into Pontiac engines.
Pontiac engines
Pontiac info and sites
 

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Looks like the OP got scared off. Too bad, we could handle a few more pontiac fans around here. We also need a couple good Mopar guys and some ford guys. Everyone is such the fan of the bowtie, which is fine, but variety is the spice of life, even in cars.
 

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Looks like the OP got scared off. Too bad, we could handle a few more pontiac fans around here. We also need a couple good Mopar guys and some ford guys. Everyone is such the fan of the bowtie, which is fine, but variety is the spice of life, even in cars.
I'm a pontiac guy.. on a bowtie budget..

they didn't have what they have for pontiac when I defected..
forged rods where huge money.. alum heads unheard of, unless you had deep pockets..
 

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I love Pontiacs. They are awesome.
Lots of good stuff available for pontiacs nowadays.
I have a 350 in my 64 now.
Have a 389 punched to 400 that will be completed in a few more months.
I also have a 400 that is all stock, just for a spare.
I also have a 428 from a 68 bonneville that needs a complete rebuild, not because it is worn out, just from setting so long

Contrary to what some of the posts here say....375 horses on pump gas is easy with a pontiac 400.Without breaking the bank.
Knowing what to do is key.
Waiting for the OP to come back so as to help him out.
 

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Faith - Respect - Trust
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I love Pontiacs. They are awesome.
Lots of good stuff available for pontiacs nowadays.
I have a 350 in my 64 now.
Have a 389 punched to 400 that will be completed in a few more months.
I also have a 400 that is all stock, just for a spare.
I also have a 428 from a 68 bonneville that needs a complete rebuild, not because it is worn out, just from setting so long

Contrary to what some of the posts here say....375 horses on pump gas is easy with a pontiac 400.Without breaking the bank.
Knowing what to do is key.
Waiting for the OP to come back so as to help him out.


I agree...your 428's got the 375 HP and more with just a diligent rebuild, cam, headers and intake (some where factory rated at that). I've built a few with great results.
 

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mr mighty mouse
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Looks like the OP got scared off. Too bad, we could handle a few more pontiac fans around here. We also need a couple good Mopar guys and some ford guys. Everyone is such the fan of the bowtie, which is fine, but variety is the spice of life, even in cars.
Im considering finding a 351 ford engine and camming it up. the problem is, how to find the older ford trucks.
 

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I'm a pontiac guy.. on a bowtie budget..

they didn't have what they have for pontiac when I defected..
forged rods where huge money.. alum heads unheard of, unless you had deep pockets..
A 389/400 Pontiac is under-cammed from the factory. I had a new 1969 Firebird 400, 335 HP, 4-speed, 3.36:1 cogs. When I purchased the car in 1970, it had 4,000 miles on the odometer. I had the Firebird for 6 months and 6,000 miles and blew the clutch, rear end and bent the drive shaft.

A Pontiac Representative from the Dallas Zone Office came 200 miles to my home town and agreed to replaced the rear end and drive shaft under the 50,000 mile drive line warranty. He told me to get a new drive shaft out of a Firebird that was siting on the new car sales lot and install it. I bought a Schiefer Rev-Loc clutch and pressure plate at J.C. Penney. What is a miracle, he knew I had been drag racing the car with 11" Goodyear wrinkle wall slicks!

The dealership installed a 4.33:1 4-pinion Saf-T-Track because the open 10-bolt 2-pinion differentials were too weak for drag racing with good bite. The 4.33:1 would cause the stock hydraulic camshaft in the 400 CI engine to run out of breath at 4,000 RPM , just like a rev limiter.

I re-built the OE #48 heads, roller rocker arms, BB Chevy valve springs, Crane ZIP-510 solid flat tappet camshaft, and 1965 Corvette edge orifice restricted lifters. That woke that engine UP!!!! I raced at Dallas International Motor Speedway in Lewisville Texas, turning 13.80 -14.0 ET with 1969 Firebird HO exhaust manifolds and chambered exhaust. In 1970, at DIMS, I was beaten in the first round of D/S by a 1969 American Motors 390 CI AMX, with a mid-13 ET.

I still have the Pontiac Crane ZIP-510 solid lifter camshaft:
Single pattern, solid flat tappet
.534" valve lift w/1.5 rockers
310 deg. duration @ .004" lift.
254 deg. duration @ .050" lift
84 deg. overlap
.028" I - .032" E lash
108 deg. LSA
102 deg. LCA (5 deg. advanced)
 
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