In over my head a bit here!

Bought a used 383 from a guy that I trust. He said he ordered it from the back of a car mag about 12 years ago as a turn-key crate motor and ran it in his plow truck for 231 hours (according to the meter). Truck rotted away and I bought the heart! Motor had never been opened up; not even the valve covers!

Now the problem is that I have no idea what is inside this thing. He remembered Keith Black pistons and an Edelbrock cam... but who knows.

It's the old school 383 build with a 400 crank.

Had a flexplate on it but I need a flywheel for my Firebird. I have that still if it'll help me figure out what I need.

The heads on it are 882's but have 4 broken exhaust studs and 4 broken (or sheared off I should say) spark plugs. Since these are sucky truck heads and prone to cracking I wanted to upgrade them to something better. Found some Patriot Performance aluminum heads that I think I'll go for but I was worried about compression.

Block number is 3970010

So, question time!

What flywheel do I need? For a 400, correct? 153 tooth? Any special balancing?

Anyone recognize the pistons? And how do I know how much the block has been decked? Don't have any idea what the compression is.

What about head gasket thickness? How do you go about figuring that out? I have the head gaskets I removed from the motor to measure if needed.

Pushrods... once again, I don't know what the motor has been decked so I don't know the length... just measure them, right? I'd just reuse what I pulled out but the head slipped when I was removing it and I think I bent one or two. Just assume replace the set.

The harmonic balancer is special for a 383 build too, right? I don't think I'll need to change that for any reason. Hopefully the March setup I picked up will bolt onto everything ok.

It has a big Moroso pan on it too. Shouldn't have any clearance issues though right?

The lifters... found four that were stuck with baked on oil. What would have caused this? Could anything be damaged from it?

Sorry for all the (probably noob) questions! I'm sure I'll have more as I go but at least I'm having fun!

Thanks!

 

First, those pistons are domed pistons which will have a higher compression ratio. If you are stuck using those pistons, I would look for heads with the 76cc chamber to help keep some of the compression down so you can at lease use pump gas and not have to always use racing fuel.

Second, pistons may have a part number on them and you can look the part number up online. Hopefully those are forged pistons.

To find out if the block has been decked, just measure one of the pistons that is all the way up an measure the gap between the outer flat part of the piston and the block. If there is no gap, odds are the block has been decked.

As far as head gaskets, you probably want to stick around with the .039 - .041 head gasket thickness which I think is around the fel-pro 1010 head gaskets.

I also think for a flywheel and harmonic balancer, you will need to know if you need an external balanced balancer or if the motor was internally balanced. You can probably use a ati or what ever you prefer and may just have to get the complete internal assembly along with the flywheel rebalanced.

I think that most of this will depend on what you want to use this motor for, street, street/strip or just strip.

Also, those look like flat tappet Hydraulic lifters. If you are content with using that same cam, definitely get a new set of lifters and maybe pull the cam to find out the manufacturer of the cam and get their lifters. The cam should have a part number on the back and you can search the cam specs online also. You may also want to check the cam lobes to see if any lobes were wiped or flattened.

If you are not looking to spend alot of money on heads, I would look into the world products sportsman heads if this is a street motor with some strip use. Granted they are the iron heads, but offer more torque and I am pretty sure the offer better flowing than those patriot heads. But if money is not an issue for heads, look into the AFR 195 heads.

Hope this helps getting you started.

 

Thanks for all the info. I'm still kinda drowning in this rebuild as I'm just so overwhelmed!

On the pistons/compression, can I just run a slightly thicker headgasket to alleviate some of that if I go with small chamber heads? Reason I ask is below.

If the pistons have part numbers, they aren't on the top surface :/

I'll spin the crank and see if the block has been decked.

I have no idea if the motor is internally balanced or not but I don't think it is. I've read most all 350/400 383 combos aren't and require the special harmonic balancer and flywheel/flexplate. I've posted a pic below of the flex hoping that'll clue someone in!

Using this motor for a daily driver / weekend warrior. Not dedicated race use.

The cam is an Edelbrock Performer RPM (supposedly). I'm up for new lifters, any suggestions besides pulling the cam? Lobes show no wear that I can see through the lifter holes.

I picked up a set of heads that need some shining (but no broken bolts to deal with!). They're Patriot Performance Freedom series which are 64cc I believe. Hoping these will work well with my combo!

 

If it were me, I'd take the block down to bare, have a machine shop clean it up, check the crank and resize the rods. Replace what is worn or broken. That is substantial damage for such a low hour engine. The can is highly suspect due to the damage to the lifters. You need to inspect the whole thing. How bummed would you be to put it all in and have it fail because of a spun bearing, or worn cam lobes that you can't see.

As far as the heads go. What runner volume are they? Are they too small or large for what rpms you want to turn and what the engine needs to breathe properly? You could pick up a set of flat top pistons for not too much scratch and know for sure that the compression won't be too high.

If the bottom end is good and the cam is reusable, it is not a huge amount to invest at a machine shop for peace of mind.

 

See the problem is that I'm already in over my head (both motor-wise and money-wise) and I'm affraid to go much deeper thinking I'll just never finish the project. I wasn't even expecting to pull the heads but I had broken studs that needed to go to the machine shop!

What damage can be caused by stuck lifters? Will it be scraping/gouging on the cam that's obvious through the lifter hole or something else? I'm guessing the lifters themselves as well as the pushrods could be bent or something so those will get replaced.

I know nothing about the heads but I think these are them: http://www.carcraft.com/techarticles...m_heads_64_cc/
http://www.jegs.com/i/ProMaxx-Perfor.../2120/10002/-1

As for the guts, nothing is worn as the motor is barely broken in and nothing should be broken as it sounded OK. I don't expect to find anything beyond these lifters but I do understand what you mean, you just never know.

 

12 years old and spent a lot of time just sitting. Oil and water (condensation) sat inside and gunked up the works. Tear it apart, clean and make sure everything is good, or slap it together and roll the dice that things are good.

Stuck lifters likely caused some cam damage. Do you want to find a flat lobe now, or after the engine is in the car?

As far as head gasket, find out how far in the hole the pistons are, then aim for a total quench height (piston to head) of .035"-.045". That is: if the pistons are stock .025" in the hole, use an .015" gasket = .040". If it's been decked and the pistons are 0" in the hole, then use the .040"-.045" gasket.

 

Ok, I'll start there. As for tearing down... we'll see. I understand I'm taking a gamble just running it if I do. Will have to see how the funds are.

 

Those heads might work, though most people here would go with a different brand. There are some iffy reviews on those, just make sure the castings are good, as QC for some real budget heads tend to be spotty.
Dart, Profiler, AFR, in a pinch some world sportsman 2 heads would be better but it really depends on the cam specs and intake you are using.

Those heads, depending on cam limits and intake are good till around 6800rpm. I'd imagine that's too much for that bottom end. 195-210cc would be better for your application.

Again, your cam must match the heads and intake, or it won't run well, or it will fall on its face before making power.


If you are absolutely sure your bottom end is without fault and the pistons are still in good shape, I'd still pull that cam. You need to see the whole cam, all the lobes.

If you want more power up top, seeing that this motor was in a work truck, a cam to optimise the desired rpm range would need to be installed.

Also, do you have a higher stall torque converter?

The whole top end needs to be matched. The bottom has to be strong enough to turn rpms at the desired speed, and the transmision and rear has to be strong enough to take the torque. Do a search here for 383 builds. There are a bunch of folks that have run very satisfying combos.

The worst thing you can do is to slap together a bunch of Chinese parts haphazardly to save a few bones.

Don't get discouraged though. This board is a wealth of info. Take your time. I've been building my 355 for over two years. It won't be complete for another two. The driveline will be done in a couple months.

 

Heads checked out OK and were barely used. Got a great deal on them so that'll help.

So, with my bottom end the way it is and the heads I've chosen, I now need a cam/lifter set that'll work the best with what I have.

I understand the cam might be damaged and probably isn't the proper grind for what I'm doing anyways.

After choosing the proper head gasket thickness as mentioned above, I'm also going to need to measure for new pushrods right? Need to replace them anyways as they might be bent from the lifters.

Also want to order the proper matching valve springs for everything too.

I'm running a T5; only posted the flexplate as it came on the motor and I was hoping it'd help identify if I need a balanced flywheel or not as I have no idea if this rotating assembly is balanced internally!

I'm satisfied with the rest of my drivetrain, just need to get the proper parts for the motor and drop it in!

 

engines in plow truck live hard lives.


The cylinder walls look good, they still have cross hatching..

There is nothing special about the pistons they are flat tops with valve reliefs, they are dished NOT DOMED. They are not high compression pistons.
64 CC heads should be fine.. but a machine shop can CC the piston and head and do the math to determine static CR so you are not left guessing.

Odds In a plow truck with GM iron heads your buddy just ran regular unleaded in it.

I cannot comment on the lifters because I am not there.

I would do the right thing.. not the easy thing..

The right thing is to take it to a shop and have it checked and refreshed if needed. (bearings, rings, re-hone, fresh gaskets.)

They can also assess the cam and lifters. etc.


you can do it right once or pay more by doing it over... and over.. until you
get it right.

 

What rpm range are you looking for?

 

Yeah, I'm guessing he didn't baby this thing... had the original plugs in it and it hadn't ever had a bath!

Good to know I have standard (albeit weird looking) pistons. Even better that 64cc should work ok!

I'll try and find a reasonable local shop to check it all out I guess. Really wanted to say I did it all but I'm way over my head. I've called a few places but the prices are nuts... unless that's just how it is. Was looking at nearly $200 just to have my other heads checked out!

As for RPM range, this is a daily driver with a T5... so nothing nuts. Beyond that I had nothing particular in mind I guess.

 

Nothing weird looking about the pistons,

Those pockets are called valve reliefs. You may have a cam with alot of lift, the reliefs keep the valves from hitting the pistons and are very common on high-perf engines. You did say this was a 383 crate engine?

 

Yes, mail order from the back of a magazine or something around 1999.

 

LOL, and you expect a machine shop to work for free?

200 $ is fair to inspect a set of heads.


You are paying for their expertise, craftsmanship, specialized equipment, rent, lighting, and payroll, not to mention the parts you need for the re-build.

I have had 2 engines built in 16 years a 383 and a 421.

I sold the 383 in 2012 and it's still going strong in a '57 Chevy.

A well built engine will last a long time with basic maintenance..

I would not even bother building my own engine because after all the machining it's only a couple hundred bucks for final assembly and that person builds them all day. So I let the shop deal with that task and I take care of the rest.

 

Yup, took the words right out of my mouth.

What does that have to do with being a crate motor? Your questions make no sense.

 

For less about 1 grand you should be able to have that motor inspected and refreshed if all it needs is bearings, rings, gaskets, and reassembly.

heads, cam, etc wil add to that.. depends on what you want to do..

 

valve reliefs are common, I can tell you are new to this, that is all..

best of luck !

 

As for cam selection, I'd go with something in the 280 or 290 range. Your shift points should me in the mid to high 6000s. (Though, I still think you are over heading the car a bit with those 235s because you don't really know what type of rods and crank you have, or their ability to Rev that high. )

IMHO, a 64cc, 195-210cc head with a 280 cam, with springs that will handle it would be what you want, seeing as you said you want a good Street car.

If the bottom end is stockish cast stuff, (even if the pistons are forged) it's only good till 450/500 crank hp, around 5800-6000 rpm. Especially considering you don't know what rod bolts were used. You need a quality set of strong bolts or your rotating assembly will come apart. More power and higher revs, you need a really strong bottom.

To the T5.... has it been built? They are hit and miss, depending on how it was used before and how it was maintained. They are not rated for lots of torque from the factory. Some people have had luck, some have trashed theirs on a stock motor.

What about your rear end? Is it stock or are you going to have it built, or replace it with a 9", or 12 bolt?

I know it's daunting, but you need to think about the WHOLE package, and how the entire car will react to throwing a motor with double or triple the power in it. I only expect around 350whp tops, in mine, and though I have an auto trans, I put a brand new bottom, brand new top end, switched from tpi to a HSR, got a edge tq converter, had a 1700 dollar trans built, and fully expect to have to rebuild my 9 bolt or just replace the whole thing when I kill it. Your power levels will be greater.

My point is to illustrate that it is not as simple to just swap a motor in. And that you should think about all the effects that a fresh engine will have, and what you may have to deal with.

Take your time, save some cash, do it right. You will be happier, and your car will thank you.

 

A wise older man told me long ago: When building car start from the rear end and work your way forward to the engine.

 

... unless your engine is already trashed. But, yes, that is sage wisdom. It is always wiser to biuld a strong foundation before you realize you really need it. ..... me, I'm not wise, and I *think* I can be gentle till I get my rear done. .....

 

Pop your lifters out and check them for cupping on the bottom and scoring on the sides. If none clean them with brake cleaner and soak them in 30 weight. Then test for a collapsed lifter by pushing down on the inside with a pushrod, if they collapse easy or don't come back up after you push them down replace them. Otherwise it is just varnish from sitting once you clean them they are fine. I would pull the cam and look at the lobes, if they look ok, reassemble the valvetrain and turn the motor over by hand with a wrench and check the movement on each valve. None of this takes money.

 

Finally some possible good news! That's more up my alley for what I can afford to do right now

I'll dig into it soon and post the results!