Author Topic: 400 pontiac engine weight vs Chevy Big Block  (Read 9266 times)

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Offline RainMan

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400 pontiac engine weight vs Chevy Big Block
« on: September 16, 2009, 10:44:33 AM »
I have searched ,and not been able to find any info on what the factory cast 400 weighs? I read a 454 weighs 485 ,and that with aluminum heads and intake it only shaves off about a 100 pounds .
I was kinda curious more than anything about the comparison of the 2 . I wonder how much a 400 would weigh with aluminum heads and intake .
I did read in some other forum that the pontiac is about 75 pounds lighter than the BBC . I don't know if this info is correct or not .That would be a benefit for the pontiac right  off the get go imo .

Someday when I get the funding ,I would like to put my numbers matching 400 in storage ,and build a stroker for the Marty . I see they actually make new blocks by Butler .
I wonder about going with aluminum for the block though ,as it makes me a little nervouse when I think about tighning a head bolt into straight aluminum . Maybe I am concerned about nothing ? I mean an all aluminum engine would be awesome ,better handling and weight distribution . I am sure you would have to get new front srpings just to keep the height down to factory specs again .
Anyways,for the most part I was curious about the differant amount of weight that would be involved for a BBC ,to a pontiac
« Last Edit: September 16, 2009, 10:46:21 AM by RainMan »

Offline turbota400

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Re: 400 pontiac engine weight vs Chevy Big Block
« Reply #1 on: September 16, 2009, 12:17:37 PM »
That's about right, a BBC is 75 - 100 pounds heavier than a Pontiac. 
Shawn
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Offline LOMILETA

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Re: 400 pontiac engine weight vs Chevy Big Block
« Reply #2 on: September 16, 2009, 12:30:11 PM »
how about a Buick 455.
The 455 was one of the first "thin-wall casting" engine blocks, and because of this advance in production technology it weighs significantly less than other engines of comparable size (for example, 150 lb (68 kg) less than a Chevrolet 454).
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Offline RainMan

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Re: 400 pontiac engine weight vs Chevy Big Block
« Reply #3 on: September 16, 2009, 12:41:28 PM »
You know ,I never thought about the pontiac being a thin wall casting . But when you think about it ,there has to be weight reduction some where in order to be 75 pounds lighter?
A thin casting kinda gives me a bad taste in my mouth lol . But I guess they seem to work . Are pontiacs more prone to over heating issues than a BBC because of the thin wall casting?
I actaully read that some where that  pontiac block's have actually broke in half?  Now that would be a major ,even the crank would be unsalvagable .
I gotta quit reading I guess ,the more I do the more paranoid I get .
Besides there's no way to get a shaker to fit a BBC that I know of .  The only other option is a SMC . But I am still thinking a T/A is not the same unless it has a pontiac engine . Although I realise they put the SBC in 80 and up regardless .

Offline LOMILETA

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Re: 400 pontiac engine weight vs Chevy Big Block
« Reply #4 on: September 16, 2009, 12:44:18 PM »
Look at the pics of Poorboys car, he has a chevy 502 and the shaker fits on it.
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Offline Joker (§ir£Ğragon)

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Re: 400 pontiac engine weight vs Chevy Big Block
« Reply #5 on: September 16, 2009, 12:53:55 PM »
I actaully read that some where that  pontiac block's have actually broke in half?  Now that would be a major ,even the crank would be unsalvagable .

That can happen to any engine. There are many different things that can cause major, catastrophic failure like that like a weakening/defect of the casting and/or over-revving for example.


The only other option is a SMC .

Now you know what my reaction to that statement is, right?
Larry


Offline Anderson0741

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Re: 400 pontiac engine weight vs Chevy Big Block
« Reply #6 on: September 16, 2009, 12:58:43 PM »
The buick 455 weighed about as much as a small block chevy

Offline Mr. P-Body

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Re: 400 pontiac engine weight vs Chevy Big Block
« Reply #7 on: September 16, 2009, 02:47:21 PM »


   Pontiac V8s, "ready to ship", weigh in right at 650 lbs.  That's with iron heads and a aluminum intake, no exhaust.

   An iron-headed BBC weighs right at 800-820 lbs. Aluminum heads will save about 100 lbs.  IMO, the sheer weight is the ONLY real "drawback" to BBC.  GREAT engines.

   Pontiac blocks HAVE been known to "split". The vast majority I've seen have been 455s. A 455 Pontiac block is weaker than a 400 Pontiac block, due to the "hole" down the middle being larger. The crank is NOT the "weak link" in ANY Pontiac build.  Also, ALL of the "split" blocks were "race" engines, over 750 HP, revving beyond 7,000. 

   The Buick 455 IS light. As a "stocker", it's a good engine, making lots of torque. Due to the "thin wall" casting, it is rather weak. Pumping up the Buick CAN be done, but it must be done very carefully.  Once the block's ability to withstand the "pounding" of racing is exceeded, the block flexes too much and the crank breaks.  We have one example "out there" running mid 10s in a 3,400 lb. car. It never exceeds 6,000 RPM.

   When the 400 Pontiac was introduced in '67, it was hailed as a "thin wall casting".  While the cylinders ARE a bit "thinner" than the older 389s, the extrerior walls are a bit thicker, making it a stronger block. The exterior walls of the 389 were prone to cracking, so the changes were made.  The 400 block weighs MAYBE 25 lbs. less than the 389.  IMO, the 400 is the best of the "lot".

   Camaros have BBCs in them. (real) Firebirds have Pontiacs...(:-

FWIW

Jim

Offline RainMan

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Re: 400 pontiac engine weight vs Chevy Big Block
« Reply #8 on: September 16, 2009, 03:47:59 PM »
Thank you for the reply Guys ,and Thank you for posting Jim .
 I am not at a stage where I can afford to get a new engine ,but more or less trying to see options .
In the future I am not really going to be very happy with 180 HP ,I can see that right now .
I don't want a 600HP engine ,or a 7000 rpm screamer  , a lumpy cam,or forced to use 4.11 gears ,just enough HP where you don't have to try very hard to peel rubber in first ,and some 2nd gear tire spin would be kinda nice .The car is an auto ,that part sucks ,but I want to keep it stock .
 
I really want to keep things looking as  stock as possible ,
so maybe it would be better to take my 400 I have now ,and someday get the stroker crank  and 455 pistons . I guess a person could always paint aluminum heads to have the stock look?  I wonder if getting the block to accept 455 pistons  would be on the thin side? Or should a person just rebore 30 over and use the next size of 400 pistons, that way keeping the wall thinkness as thick as possible.
I read that people were boring it out further to except 455 pistons ,more or less to same money .I can't see the added cubic inches making a big differance bore wise with the 455 pistons .

Or maybe bite the bullet and build a completely differant engine . I could see a Butler engine build adding up fast . 15 G  would probably be just a good start . As you may as well start from the ground up with one of there new block's considering you are getting newer proven technology.  Don't know how stock it would look though . You would think the block should look simular enough for the average person off the street not to notice .
But I suspect most people are building Butler engines for 9 second quarter miles lol . Next I'll have to strengthen the frame , tranny,diff  ,etc  YIKES this is getting out of hand  :o


btw Mr P body ,you are right ,a real Firebird has a Pontiac engine . It pains me to even think of a chevy engine in a T/A
« Last Edit: September 16, 2009, 04:11:20 PM by RainMan »

Offline SavingTheBird76

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Re: 400 pontiac engine weight vs Chevy Big Block
« Reply #9 on: September 16, 2009, 04:30:40 PM »
You would be better off building your 400.
The big block chevy is not only heavier,but wider and taller.
If you really want to store your current engine,don't go with a Buick 455.
The Buick needs a lot of mods to make big horsepower,and has a weak oiling system.
I have a 73 centurion,and parts are extremely expensive.
High performance rebuilds usually require girdles,along with other strengthing of the blocks.
Torque is the mainstay of the Buick motors,not high rpm or horsepower.
The pontiac motors are engineered better,IMHO.

The chevy Big block is a heck of a motor,but I don't see many in pony cars.
I imagine the suspension takes quite a beating with the added weight.
A full framed car would carry the Big chevy a little better.
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Offline LOMILETA

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Re: 400 pontiac engine weight vs Chevy Big Block
« Reply #10 on: September 16, 2009, 04:55:27 PM »

If you really want to store your current engine,don't go with a Buick 455.
The Buick needs a lot of mods to make big horsepower,and has a weak oiling system.
I have a 73 centurion,and parts are extremely expensive.
High performance rebuilds usually require girdles,along with other strengthing of the blocks.
Torque is the mainstay of the Buick motors,not high rpm or horsepower.
The pontiac motors are engineered better,IMHO.


 Im not trying to be an a** or argumentitive, just stating FACTS as I have seen them.

I have just over 5K in MY Buick build, with a complete stock bottom end.. No girdle, No other strengthing of the block, yet is was dynoed at 575hp and 565 lb/ft. My brother has been running solid high 10s for over 5 years with the exact same combo without any problems. I also have friends that are running faster, well into the 7k rpm range. Oh and the oiling mods cost me about $250. I understand that this is a Pontiac forum and my thoughts are the minority. I didnt plan on building a Buick, but I am very happy with what I have now.
« Last Edit: September 16, 2009, 05:00:59 PM by LOMILETA »
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Offline RainMan

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Re: 400 pontiac engine weight vs Chevy Big Block
« Reply #11 on: September 16, 2009, 04:56:39 PM »
You would be better off building your 400.
The big block chevy is not only heavier,but wider and taller.
If you really want to store your current engine,don't go with a Buick 455.
The Buick needs a lot of mods to make big horsepower,and has a weak oiling system.
I have a 73 centurion,and parts are extremely expensive.
High performance rebuilds usually require girdles,along with other strengthing of the blocks.
Torque is the mainstay of the Buick motors,not high rpm or horsepower.
The pontiac motors are engineered better,IMHO.

The chevy Big block is a heck of a motor,but I don't see many in pony cars.
I imagine the suspension takes quite a beating with the added weight.
A full framed car would carry the Big chevy a little better.

I would not go with a buick . I pretty much would stay with a pontiac engine only . Seems like  a pain somedays ,but it's pretty much the only option to me.
I did not though there were readily available parts for pontiacs anymore . I found a few links ,and you can buy an actual aluminum or cast block brand new .
All aluminum would be the ultimate ,but a could see me stripping a bolt and going off the deep end lol .
I think a stroker 400 with modern aluminum heads and intake may be the answer .  Just as long as the shaker height stays correct
« Last Edit: September 16, 2009, 05:02:53 PM by RainMan »

Offline RainMan

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Re: 400 pontiac engine weight vs Chevy Big Block
« Reply #12 on: September 16, 2009, 04:58:09 PM »
Quote
I have just over 5K in MY Buick build, with a complete stock bottom end.. No girdle, No other strengthing of the block, yet is was dynoed at 575hp and 565 lb/ft. My brother has been running solid high 10s for over 5 years without any problems. I also have friends that are running faster, well itno the 7k rpm range. Oh and the oiling mods cost me about $250.

Wow those are some impressive numbers .I'd be happy with HP in the mid 400's
« Last Edit: September 16, 2009, 05:01:43 PM by RainMan »

Offline LOMILETA

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Re: 400 pontiac engine weight vs Chevy Big Block
« Reply #13 on: September 16, 2009, 05:04:44 PM »
Think about this, most Trans ams didnt come from the factory with a Pontiac motor. All of them from 69-76 did. Then from 77-81 they could have had a Pontiac, Chevy, or an Olds. After 92 ALL cars came with a Chevy motor!  Unlike others here I didnt say the Buick motor was better than the Pontiac, I just pointed out what I have done and seen done.
« Last Edit: September 16, 2009, 05:08:01 PM by LOMILETA »
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Offline Anderson0741

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Re: 400 pontiac engine weight vs Chevy Big Block
« Reply #14 on: September 16, 2009, 05:09:55 PM »
77-79 Trans Ams didnt have a chevy engine