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So I am looking at this 400 SBC...


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So I bought a 280z v8 project from a member on these forms, and the history of the car isn't enw to SBC's and even a 454 bbc. I got all the mounts and goodies and it already has a th350 trans and driveline all hooked up, so I am leaving it be like that for a while. Anyways, I have been looking for a 327, 350, or 400 sbc for about 3 weeks now and I came across a 400 SBC out of a 77 suburban. I went clear out into the mountains to look at it, and since the guy scrapped the body off the frame I had to do a little work to prepare it for a start. It had been mostly sitting for the last five years with a few starts between. Anways, once we got a good cconnection to the ignition and starter it all fired right up. The deal is really too good to pass IMO. The oil was slightly greyed from the high mountain moisture we get in idaho, but after inspecting the spark plugs (No signs of burning oil) and looking at the rockers none or light deposit on the underside of rockers, mostly none). So that's the history and inspection, its a 4bbl and i ran it up to about 4500 rpms and it sounded excellent all the way through. He told me he thought it had 140k on it, but when he got the truck it had all been serviced, and the motor looked real clean for that many miles. My guess would be a rebuild within 30k

 

So My game plan as of right now (If you all even still think this is a worthy engine) is to probably dress up the tin and replace the head gaskets and clean the short block and heads as best as I can and reassemble the engine. Next year I will look into rebuilding this engine or another, right now I just want to get the car driving. I would be interested in a little more performance, so if anyone has a cam or cylinder head recomendations, all ears (just dont' break the bank).

 

Anyways, that's me speaking, looking to hear any and all recomendations. I know the 400 gets a lots of fans and naysayers, and there is 19 pages relating to "400" which I read allthe posts actually discusing the 400 sbc, But honestly, I was looking for a more solid answer "Hey do this on a budget" or "hold off, the engine might not be for you".

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sounds like a good starting point. i work in an engine shop doing mostly high end and somewhat budget performance builds. forget what people might say. the 400 is not really a bad starting point. if you think its too good to pass up then go for it. you will have fun with it and most important you want to stay within your budget. every buck saved can go to some nice goodies as extras. plus you can build a nice 434ci stroker out of it.

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My only hold back is the slightly greyed oil. he said it was SAE 30w, the oil looked like it should have high milage as did the plugs, but the oil had kinda like a silty grey to it.Even after the engine churned it up some, still grey like. But there wasn't any appearance of rust oor resistance in the engine turning over. Everything seems perfect, everything was intact as is minus the ignition wiring and the heater core.

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you should expect condensation. and it's not gonna disappear that quick. it takes a few oil changes to clear out water. however i can understand your reservations with it. if its a good enough deal get the heads checked out after you get it. or look for something that has not been sitting as long in the mountains as long. you can hit me on aim if you want to further talk about it.

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Thanks a lot, I felt good about it. But my dad got me all sorts of worried reminding me about the shallow water jackets ect ect. Honestly, I was very impressed with the engine. Any tips for good performance upgrades without going too far. honestly, i'm a college student, so lets keep it cheap and relaiable.

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set of cheap aftermarket alum heads machined for a 400 (i just happen to have a set i need to get rid of brand new. casting but ill sell them assembled just PM me.) good intake, good cam( PM me about the cam too). and if possible bore it and put a set of forged pistons in it. but a good cam and a better set of heads will make you happy with the right intake can carb combo

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A 400 SBC from a 1977 Suburban will serve as reasonable foundation, but don't expect impressive hp. The top model for that year, a 454, would barely crack 200 hp.

 

That said, resist the temptation to make even minor modifications. It is easy to ruin an otherwise serviceable combo by tinkering here and there. Example: installing new flat-tappet cam; excellent way to wipe the lobes and to send lobe/lifter material all through the oil gallery and into the bearing shells. So, buy the engine, keep it stock, get your car running, become familiar with it, and only subsequently entertain notions of modifications.

 

BTW you mentioned that your Z went through a stint with a 454. What happened? Why was it removed?

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I'm not teribly sure why the big block went, possibly sold for some money at the time? reguardless of why it went I am certain about wanting the small block lol. Wouldn't replacing the heads and cam as well as intake be a good enough upgrade?

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My only hold back is the slightly greyed oil. he said it was SAE 30w, the oil looked like it should have high mileage as did the plugs, but the oil had kinda like a silty grey to it.Even after the engine churned it up some, still grey like. But there wasn't any appearance of rust oor resistance in the engine turning over. Everything seems perfect, everything was intact as is minus the ignition wiring and the heater core.

 

It looks as though you have found the one very important clue in the silty grey oil. Should be blacker than grey. Suspect a water leak in the block. Drain the oil from the pan and leave the oil plug out. If the radiator is still there, fill the cooling system with water and obtain a pressure pump and adapters for radiator neck. Pressurize the system and look for water leaks especially from the oil pan. Small Block Chev's of that generation can suffer from core shift when the block was cast. The 400 small block may have weak spots in the cylinder bores. The only way to truly know is complete dis-assembly and sonic test each bore for wall thickness. Should be approx 0.200" minimum.

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It looks as though you have found the one very important clue in the silty grey oil. Should be blacker than grey. Suspect a water leak in the block. Drain the oil from the pan and leave the oil plug out. If the radiator is still there, fill the cooling system with water and obtain a pressure pump and adapters for radiator neck. Pressurize the system and look for water leaks especially from the oil pan. Small Block Chev's of that generation can suffer from core shift when the block was cast. The 400 small block may have weak spots in the cylinder bores. The only way to truly know is complete dis-assembly and sonic test each bore for wall thickness. Should be approx 0.200" minimum.

 

The whole system was there except ignition and heater core. and it was still completely full of fluid. the collor didn't get any worrse or better after running it for 10 minutes

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And wouldn't the engine have had some sort of indicaator, like a miss or a slosh in one of the cylinders when running it? I ran it for 10 minutes from idle to about 4500 RPM several times and it acted like any good solid 350 i've ever looked at.

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And wouldn't the engine have had some sort of indicaator, like a miss or a slosh in one of the cylinders when running it? I ran it for 10 minutes from idle to about 4500 RPM several times and it acted like any good solid 350 i've ever looked at.

 

If you were able to run the 400 SBC then the ignition MUST have been working. Gave this situation further thought and there is a cooling system sealant that is powdered lead that is supposed to bunch up at the leak and stop same. Suspect this sealant was used and there is or was a cooling system leak into the lubrication system. Highly suspect there is a head gasket leak or at worst a hole in one water jackets of the cylinders to the crankcase. The only items of ANY VALUE are the block and crankshaft. The remainder will need to be replaced at rebuild provided the block is OK. The low cost cylinder heads with best performance for the price will be the Vortec Cylinder heads. Be careful, get cylinder heads at a reasonable cost that have been reconditioned or new. Get the block sonic tested FIRST if torn down BEFORE proceeding ANY FURTHER. The cylinder heads, camshaft, intake manifold and fuel control will dictate the amount of power generated. The more spent on cylinder heads, camshaft and induction system the more power generated.

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Well yea the ignition system was still hooked up, but what I was meaning is I had to splice it back together since the ignition switch was no longer present. Wish I had a picture availible of the oil color, but it looked like sculpting clay. It still seemed like the right consistency, not watery. There wasn't any sort of build up on the oil cap or the dip stick. I called the guy while he was at work and then followed him home from work, so I don't think he or one of his 3 daughters messed with the engine to make it appear better then it was. This is just a first time encounter for me with greyed oil. Everything seemed to check out fine. The engine is only $250 I pretty much have between now and friday to make a final descision as to whether or not I want it when I go to pull it (myself from the frame and trany) I get the complete engine, AC compressor/condensor, radiator, long tube headers, and any ammount of exaust I want with the manifolds. It's currently 3 inch dual, but nothing special, just rusty tube.

It just doesn't seem like a head gasket or broken jacket because normally there is milky build up on the cap and dipstick from what I've seen. However, please educate me further if this isn't the case.

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Well yea the ignition system was still hooked up, but what I was meaning is I had to splice it back together since the ignition switch was no longer present. Wish I had a picture availible of the oil color, but it looked like sculpting clay. It still seemed like the right consistency, not watery. There wasn't any sort of build up on the oil cap or the dip stick. I called the guy while he was at work and then followed him home from work, so I don't think he or one of his 3 daughters messed with the engine to make it appear better then it was. This is just a first time encounter for me with greyed oil. Everything seemed to check out fine. The engine is only $250 I pretty much have between now and friday to make a final descision as to whether or not I want it when I go to pull it (myself from the frame and trany) I get the complete engine, AC compressor/condensor, radiator, long tube headers, and any ammount of exaust I want with the manifolds. It's currently 3 inch dual, but nothing special, just rusty tube.

It just doesn't seem like a head gasket or broken jacket because normally there is milky build up on the cap and dipstick from what I've seen. However, please educate me further if this isn't the case.

 

Don't understand the comment about sculpting clay. Is the color grey or brown/tan? Ask the owner of the suburban what caused the oil to appear the color it is. Ask if it has been rebuilt at some point and how many miles are on the engine and since rebuild if applicable. There must be a reason for the off color oil.

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it's grey, like the stone colored. It is almost grey primer color. He said the whole truck was completelly serviced before he got it about 6 years ago. It had been sitting for about 5 years with a start every now and then. Since he has owned the suburban, he never changed the oil, plugs, wires, coolant- nothing. He said the grey was from the air moisture. Last month he scraped the body off the chassis, since the interior was shot, most glass was bad, and couldn't sell it. The engine sounds great, doesn't have any odd vibrations, and fired right up with a little gas poured into the carb, whereas it remained running just fine. The oil has only one consistency, grey. It isn't watery in some parts and chalky in others as far as I can tell. Just oil, grey colored.

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Possibly this?

http://www.ford-trucks.com/forums/291591-grey-motor-oil.html

 

I don't know, i'll make sure to ask the guy more questions about the oil color. Although, I doubt he is teribbly informed, doubt he even ever checked the oil in it. Honestly all he has to tell me is he got it, ended up not really using it, started it up every now and then, and now he is tired of it and cant get rid of it.

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Possibly this?

http://www.ford-truc...-motor-oil.html

 

I don't know, i'll make sure to ask the guy more questions about the oil color. Although, I doubt he is teribbly informed, doubt he even ever checked the oil in it. Honestly all he has to tell me is he got it, ended up not really using it, started it up every now and then, and now he is tired of it and cant get rid of it.

 

Do what was done in the link that you posted. Drain the oil, check for any sign of coolant, change the filter and put in new oil if no coolant detected. Then run it till it gets up to temperature and then 15 minutes beyond getting up to temperature. Shut it down come back in an hour and check the dipstick for oil color.

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I haven't bought the engine yet. should I try to convince him to do this with me? other options?

Propose to the owner about draining checking the oil and if no moisture is found then change the filter and fill with oil that you have purchased. If the owner hesitates consider it as a sign that something major may be wrong. The other option is to purchase the engine explaining to the owner the reusable parts are the block if it passes inspection, pressure, crack, sonic testing and the magni-fluxing crankshaft. The purchase is a gamble. What is put into the block for machining and components will far outweigh the cost of the bare block. You decide.

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My opinion is to just buy it. If something is bad after you get it you'll be able to part out the rest that is coming with it. For $250 thats a drop in the "oil" so to speak. The long tube headers were are still prob worth just that.

 

Now if he was asking $1k for it then I would be a little worried.

Edited by GOTHALOSISM
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