1978 500557 block questions 50$

Pontiacpower

Pontiacpower

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Hello all. I have recently found a guy on Craigslist selling an original 400 motor from his 78 trans am. Casting number is 500557 and he said it's never been apart. I know these blocks are not as strong but for 50 bucks would I be wasting my time? It's seized up but he said it ran he pulled it. I have a 71 lemans with a 350 I would like to replace. Is the 400 a candidate for a bore and stroke increase? Or should I take the 6x heads and the crank off and scrap the block? Or not even waste my time with it? Any input is appreciated. Point me in the right direction as I'm a first timer for engine rebuilding and I would like to get between 4 and 500 horse and get it right the first time
 
Call up your local machine shop, and ask them what it would cost to clean and check all the parts you would want to use from this engine.

Since the engine seized it is possible that your 50 dollar engine may just be boat anchor that will cost hundreds of dollars to find out that it is junk.

If your a first time engine builder, ask yourself if you have all the tools to do the job properly, this project will take you longer than anything you have ever attempted on your car.

Personally my advice is stick to what your good at working overtime and side jobs to pay for a professionally built engine by Pontiac specialist that do this work all day everyday.

I would also not worry so much about horsepower and torque as much as ending up with a professionally built engine you can afford.

The friendly and knowledgeable people at Butler performance or other online sources will work with you to pick out the engine that is right for your application.

http://www.butlerperformance.com/

Picking a performance range from 400 to 500 horse power out of the sky is not as important to having an engine with the correct power band that is right for you and your intended driving habits.

A 500 horse power engine carries with it a necessity to upgrade many other things on your car to handle the power.

So be careful with what you wish for you may just get it,which could cause you more grief and unexpected expenses down the road.

I am not saying you should not build your own engine if that is a bucket list item you want to do, I am saying contact the experts that will help you select one of their engines that they recommend for you . have them send you the specs of this engine that you both agree is a good fit and go from there.

Just know that building a engine that will develop the horse power and torque you want is easy.having it stay together or perform the way you intend on it to is another.

just a wrong cam selection, can make your car where you no longer enjoy to drive it.

I do not know you, but I bet you can make more money doing what your good at, working over time or side jobs to make up for the added expense compared to trying to building the engine yourself.

Especially when you consider all the tools and equipment you will need to compete with a Butler or specialist built engine.
 
I suppose you are right. Probably should try and figure out more before attempting an engine rebuild. That or pay to have it done. I just never see 400s assembled for less than $500 here in Michigan. Thought it was a deal even for a seized motor
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I gave away a complete Pontiac 455 with high flow heads that was complete intake to oil pan, with all new machine work it just sat around too long unprotected and needed to be sent back in to be rechecked. I was in a hurry to move and didn't feel like dealing with it.

I got the motor for free from a close friend, he said it was completely rebuilt and left it in storage for years.

It sat on Craigslist for a long time in the free section and I didn't get one email call or text. finally I called my friend at the machine shop and had them pick it up.

So keep your eyes peeled one day the right deal may come around, the universe has its way of providing to those that deserve it.

I wish I had it now to give to you. All I wanted was to make sure it went to a good home and not to be sold off for a profit.

At the time I had a 1979 with a 403 and I didn't have the cash for parts to swap it over plus machine shop charges. when I moved I didn't have the room for it.

For now like I said earlier focus on finding out exactly what you want out of this new to you engine, get the specs from a professional. this way you will have a better idea of what to look for.

Many people make the mistake to say I want X amount of horse power just so they can say they have that amount for bragging rights.

Yet it takes more than horse power and torque numbers to make your car into what you want.

A well thought out car with lower horse power and lower torque that was built to maximize what it has will out perform in a drag race or a road course a car with stupid horse power and torque that cannot hook up or last long enough to finish the race.

I am not sure that came out right I guess I am getting tired.

I hope you get the point, If your car runs well doesn't smoke rattle or need a rebuild. focus your efforts on the known weakness your car does have.

Brakes, suspension, rear end, add fuel injection,cooling system, so many things can be done to your car to make it more enjoyable and reliable to drive.

once all that is dialed in and your getting the most from your car and you still need more then focus on the horse power and torque.

By then you will know what you need.
 
I do plan on doing brakes and chassis first I just figured the deal would be worth buying and sitting on that block Until I can get to it. My 350 is a dog and I just want a potent car to drive and be able to take to the strip and run decent quarter mile times
 
well for 50 bucks I agree it is a good deal. its worth that to drag it home and pull it apart.
If you have the time space and energy.

Plus it would be a good learning experience for you. I am guessing it may have other parts on it that could be cleaned up and resold on this forum or eBay.

While taking it apart label everything take pictures.

I used to clean up engine parts tins water pump housings etc recondition them and sell them on eBay. So I doubt you would lose money. even if the both heads and the block was cracked.
 
Pontiacpower said:
Hello all. I have recently found a guy on Craigslist selling an original 400 motor from his 78 trans am. Casting number is 500557 and he said it's never been apart. I know these blocks are not as strong but for 50 bucks would I be wasting my time? It's seized up but he said it ran he pulled it. I have a 71 lemans with a 350 I would like to replace. Is the 400 a candidate for a bore and stroke increase? Or should I take the 6x heads and the crank off and scrap the block? Or not even waste my time with it? Any input is appreciated. Point me in the right direction as I'm a first timer for engine rebuilding and I would like to get between 4 and 500 horse and get it right the first time
Click to expand...


Buy it.....youll be fine. If the block is cracked ( which I doubt) you can recoup the money as scrap.

Doug in P.R.:cool:
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here is a video I found that you may find interesting, You may be able to wake up your tired 350 without pulling the engine from your car.

Of course it depends on the condition of your engine.

https://youtu.be/LYs6tPCGVHU
 
Thank you all for the input. I'll clear some space and call the guy and see if he still has the engine in a week or two. I watched that video and that's pretty impressive making 350hp and 380 torque. Being my first time doing a restoration/rebuild on a car. I am overthinking the output too much. I suppose completion of a mild project will dictate what performance I would like from my car.
 
Since you have never built a engine before, perhaps a better start for you would be to wake up what you have, If you leave the rotating assembly alone and focus on the top end, camshaft etc, you will get the grease under your nails experience and fun you have been craving.

Just take your time find good deals on the parts that was suggested in the video and you may be in Pontiac bliss when your done.

he was able to this so inexpensively because much of what he needed he already had.
 
I feel you are right. I have never done anything to improve performance on a car so jumping into a full rebuild is probably a bad idea. I have however had issues with the countless cars I've owned so far and I have kept them all on the road so I know I can take on a mild build at least. Am I mistaken or is his car a 407 stroker? I watched 2 other videos of his and I thought that same car was in each one and in the title it said 407
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I just looked at all of his videos, I do not see the 407 you mention, the video I provided a link to is 4 years old. the videos that show the 413 CI was made three years ago.
So it is likely he dug deeper into the engine making further modifications.
Look closer and you will see the engine has changes made to it.

It is not uncommon for people to evolve their build as they go and this is the way you may end up going one you get used to the power and have the extra greenbacks to dig deeper into your build.
 
I did notice how he had 455 air cleaner and a few other small modifications that he pointed out. I guess the first step is a 4 barrel upgrade, I also have a set of round longtube headers sitting in the garage as well so I have stuff to do for now. My lemans needs some work to do I'll have a laundry list for this winter
 
I would suggest lets do some good old fashion testing and see what we are starting out with. If your engine needs to be rebuilt lets find out before you start bolting parts on the car.

I like to start out with a engine that is in good working order making sure it works as intended before upgrading anything.

Many inexpensively repaired things can effect the performance and fuel economy.

If your timing chain is stretched and worn out this will lower compression making your car very sluggish.

so lets see how bad it is, this test will cost nothing and you do not need any special tools.

You should check the slop or play in the timing chain, if you have a timing light, clean the harmonic balancer and timing marks either found on the balancer or the timing chain cover .

I do not remember on a Pontiac engine which has the marks for setting the timing you will have to look and see or someone else can chime in.

Using a timing light with the vacuum advance disconnected and hose plugged.

Check the timing for your engine, the mark should not move around much a few degrees is normal but if it is bouncing around a lot we need to do a manual check on the timing chain.

let the engine cool down some and crank the engine over by hand using a large ratchet and socket on the crank shaft, remove the spark plugs if you have to to make it easier. mark the wires if your unfamiliar with the fireing order.

If you remove the spark plugs keep them in order so you know what cylinder they came out of, take close up pictures of each spark plug so we can see what they look like.

Reading your spark plugs gives us a good indication of the engines condition and tune.

Make sure to rotate the engine in the normal direction of rotation, you will need to have the distributor cap off making a mark on the distributor body that points to the number one wire on the cap.

I used to have a remote starter button to help make this easier. they are still available inexpensively through harbor freight if you need one.

Either way you want to have the number one piston on the compression stroke you can tell this by having your finger plugging off the spark plug hole while you are cranking the engine over by hand or bumping it with a remote starter button.

Once you feel compression building, turn the engine the rest of the way by hand till you get to top dead center indicated by the timing marks.

If all is good the distributor should be pointing close to the number one mark you made on the distributor body it will not be exact because of the initial timing.

once your all lined up spin the engine over slowly by hand backwards from normal rotation while closely watching the distributor rotor button.

The very second that rotor button moves even a little stop turning the engine over.

Then look down at your timing marks the amount it moved shows how many degrees the the cam is off while running.

check this a few times if you think you continued to turn the engine with the rotor button moving. this takes a little patience.

If you have to recheck it just spin the engine back in the direction of normal rotation until the marks are lined back up. then try again.

If your engine shows 20 degrees movement the first time and 10 the second
keep checking it or have someone help you until you are absolutely sure the measurement you made is accurate.

A few degrees is not enough to worry about, anything excessive shows that your first improvement should be to replace the timing chain.

If you determine the chain is good, while the spark plugs are out pull a base line compression test writing down your findings and post the results.

a compression test kit can be obtained through many parts stores as part of their tool loner program.

I will take you step by step checking the engine and tune to insure we are starting off with a good engine and a well tuned engine.

With the data you collect and the parts list obtained by doing these simple test you will know what is most important to start off with first.

If your not interested in going down this road feel free to let me know so I do not waste either of our time.

If you do go down this road you will learn more about your engine than you were counting on learning.

I do not know what your experience is with cars and engines, please do not get offended if much of this sounds like common knowledge to you.

Understand I go out of my way explaining all of this to not only help you, but anyone that doesn't know these basic test and procedures and perhaps will learn something from it.

By the way if anyone that reads this notices if I miss a step or incorrectly typed something feel free to correct me. I am far from perfect or an expert.

I am sure I forgot 3/4 of what I used to know about cars and the other 1/4 I do remember may be contaminated with false information LOL.

So use common sense and whenever possible go by a manual specific to your car and engine.

The information I provide freely is general knowledge and not year make model specific. So I am counting on your skill set and reading the manual to keep you out of trouble.
 
The timing mark is on the balancer. It doesn't move at all at an idle. Thank you for all the details and procedure. When I get the car back from the body shop I will pull the plugs and see what they look like. I don't have much experience in working on cars other than maintenAince type stuff. I always manage to get my vehicles back on the road but I have not ever attempted an overhaul like this so having input from those who were fortunate enough to be driving these cars before they were considered classics is awesome
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that is great, after we read the plugs and pull a compression test we will know more about the condition of your engine. if I were you I would consider making a list of parts you want to do, cam lifters, heads, gaskets, valves and springs, push rods, intake and carburetor, exhaust etc and accumulate them and do this job all at one time when you have everything together.

this will be the most cost effective way to do the upgrade without wasting money on fluids and filters gaskets etc over and over by trying to do it in a piece at a time.

pulling these pieces on and off will add that many more chances for a mistake to happen and damage the finish of your new shiny performance parts.

Do it right and do it once it is cheaper and the end result will be much better.

If your having paint and body work done, you will want to wait for some time to work on it. even if the paint is dry it my take some time to fully cure and harden. talk to your body guy and ask how long it will take to safely put clean fender covers on it and work on it.

As far as poor performance, does your car have factory exhaust on it? meaning does it have original pipes that connect to the engine to the muffler.
I am sure the muffler and tail pipe or pipes have been replaced before.

The reason I ask in the old days the pipes that connect directly to the engine used to be heavy duty double wall tubing. over the years of the inner layer heating up and cooling down at a different rate then the outer layer would eventually cause the inner layer to collapse.

looking at the pipe even a strait section from the outside you would think the pipe is fine when in reality you may have a very large exhaust restriction.

The one car that sticks in my memory was a old Malibu that was a simple as could be, yet everything was perfect and looked great yet the car performed like it had restricted exhaust this was even supported by a vacuum gauge test. yet under the car was clear pipes going to cherry bombs I was like WTF?

an old timer at the time said remove the exhaust pipes and handed me a large ball bearing and said try and roll this through the exhaust. he bet me that if the ball didn't come out the other end I had to buy him lunch.

I told him he hit his head on the bottom of cars too many times and I added to the bet if the pipe was clear he owed me lunch and had to put the exhaust back on the car.

Sure as heck the ball you could hear rolling down the exhaust until it stopped.

I learned from that day never to bet against this old man. and I also learned he had expensive taste for lunch LOL.

BTW the exhaust did sound weird it had a slight whistling sound from it, that made this seasoned mechanic know for sure what it was along with the results from my many test. That he knew I didn't need to run.
 
Well so far I have a quadrajet with an intake, and a set of headers. I do not know what heads I have but imagine that the 6x heads on that 400 might be worth grabbing. As for exhaust, mine is pretty new. It was taken to a local shop and a whole new system was installed before I bought the car so I should not have the issue you mentioned earlier. I do not know when the car had exhaust installed but It looks like it would have been within the last 2 years. I do like your story that made me laugh. And I must thank you again for all the input your giving me on the subject, it's hard to find someone who is willing to play mentor especially on the Internet
 
Many people will say they do not like the q-jet. I like them when they are done right.

is it a used or rebuilt carburetor?
IF so
Have you checked the throttle shaft for play?

the main problems these carbs had if I remember correctly other than normal stuff were throttle shafts with excessive play, leaking well plugs.

What is the number on the Q-jet that you have?

what CFM is it?

Is it the one with the idle mixture screws originally hidden with the metal caps to prevent owner tampering? or factory exposed.

you can tell because the base of the carburetor at the idle mixture screws will look like it was mauled by a aluminum eating beaver.

The older one I think had exposed mixture screws that were not counter sunk into the base completely requiring a special tool to adjust the mixture.

The good news is the Q-jet is very easy to rebuild and parts are available I doubt you will find anything factory for it.

If you find the throttle shaft has play you can install bushings and new shaft if needed with a kit found in this link.

http://quadrajetparts.com/quadrajet-throttle-shaft-bushing-c-128_34.html

If the carburetor is a good match you can get a head start by rebuilding it and having it ready to go unless you purchased it rebuilt by a reputable place.

I will say carburetor cleaner is not as good as it used to be nor as toxic, yet you can still get some good cleaner from Napa.

this cleaner normally comes in a metal bucket some have a basket for smaller parts some do not.

You will likely only need this chemical one or twice then shove it away some where in the garage when your done.

Be careful if you do this because the metal with rust away and you will have one smelly mess on your hands.

One of my co workers did this with large 5 gallon bucket of this stuff which rotted out and leaked everywhere in his garage that was attached to his house, the smell from the chemical was bad enough, but this cleaner made its way into other chemicals he had laying around, I am not sure what.

When he came home from work the fire department was going door to door all up and down his street trying to determine where the toxic smell was coming from.

So if you have to use this chemical and not a ultrasonic parts washer use the proper PPE and store the left over chemical with a secondary containment.
 
I don't know the number on the q jet but it's from 1971 so it has accessible fuel/ air mixture screws. I also have one with the hidden mixture screws too but my uncle recommended using the 71 because it's period matching to my car. He currently has the older carb and is rebuilding it.
 
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