I'm hoping someone can give me some solid advice. I FINALLY have money in hand to get some real progress going on this project car.

The background on the car: Bought a few years ago as a $500 special. It needs work and I KNOW that. My goal is to have a streetable weekend warrior ride. There will be audio, custom interior, etc. But I want something with power.

It came with a 305 in it stock. I found a 4 bolt 350 engine (cast #330817) already bored 60 over. One of the cylinders needs sleeved which is why I was able to get a deal on it. I currently have Hooker header shorties ready to go back to my loudmouth SLP exhaust. The car was bought with a 750 Holley carb (80508) and a Weiand single plane intake (7546).

I need advice on what rotating assembly to go with as well as cams and heads as I doubt stock 305 heads will fit this project (maybe I'm wrong?).

There are NO plans to have boost or nitrous on this setup. This is a tight-budget build, so please keep from trying to sell me on top of the line race equipment.

I appreciate any and all help. Thanks!

 

A casting # 330817 block is a 400 block, not a 350.

If it's been bored 0.060" already, the first step is to spend the money on sonic and crack testing. You need to know if there is enough material left in the cylinder walls to trust the block, and if there any cracks to know if it is justified to spend any more money on it.

Did you just get a bare block, no crank or rods?

 

Yeah, I got the block by itself. The guy I bought it from said he was building it as a race motor, but the company that bored it out chipped a cylinder and wouldnt cover repairs. (which is why it needs sleeved)

 

Walk away from that block. It isn't worth it to spend money on machine work on an already .060" 400 block. Even if it checks out and you build it and run it, if anything ever happens needing more machine work you are back to finding another block. Most machinists won't take a 400 over .040", as they are already at a very thin wall with a virgin bore (4.155"). A .060" 400 block has between .2" and .25" of wall from cylinder to cylinder... which might hold under power and might not...

FYI I am running a 3.875" stroked 330817 2 bolt 400 overbored to 4.155" and I don't have a worry about the 300 pills... but I am planning on buying a bowtie HD block within the year as well..

 

If you have a 400 block that's been bored out .060" and needs repair, you might as well sleeve all the cylinders and start over with 400 CID again. There's no guarantee it will survive if you don't know what other abuses the block has gone through. Every time a block is line honed, the crankshaft moves closer to the camshaft. After 3 or more line honings, a shorter timing chain is required.

Considering GM hasn't produced a 400 block since 1979, the extra cost to recondition an old block is worth it.

Your only other alternative is to buy an aftermarket 400 block which will be a much better casting.

The only good factory 400 block to buy is one that was yanked out of a street car/truck. Then you know it may have had at least one rebuild in it's lifetime and never raced.

Since you need to buy everything else, I'd walk away from it also. What did you plan of doing with it? Street engine, race engine?

 

It was meant to be just a much needed upgrade from the 305 that came in the car. The car was not going to be raced by any means. I dont have the time or means to build what a race motor would need. With what I have in the garage and what I have in my wallet, I dont have the cash to get ANOTHER block. Although I do understand the waste it would be if this block failed.... ugh...

 

Unless you can find a virgin 400 engine, you'll be better off just getting a 350 to replace the 305.

 

Here are some pics....

 

The chip probably won't hurt anything. A shop that knew what they were doing could weld it up and remachine it.

But, it'll without doubt cost you more just to buy all the parts to put that engine together than it would to rebuild a 350 longblock.

 

I believe that chip is well above the top ring and would not cause any problems, but I am no machinist, maybe someone else will chime in?I notice in the pics that it has splayed main caps, that is about 500 dollars worth of parts and work,and the fresh bore cost over 100$, and considering all the other machine work, I am sure it has been decked, so once you consider that a 400 block sells for over 200$ and this one has at least 750 dollars worth of machine work, I would say it is worth the risk of paying for a sonic check, and if it passes buy it. This is if the owner agrees to let you(if he does not, run away!) as mentioned before 400s have thin cylinder walls and are usually not bored .060, but I have seen it done with good results. If it checks out to have sufficiant cylinder wall thickness, you will have a great block for building a potent street strip motor.

 

Do you guys think this is something I'm considering on buying?

It is sitting in my garage right now. I simply want the best way to get it into my T/A with the other parts that I have.

 

This is the message: Completing that engine would be very expensive.

Cut your losses. Sell the block if you can. Install a 350. Your goals don't justify a shaky 400 build.

Ditto the single plane intake manifold. It doesn't match your goals. Ditch it.

 

I do not see why completing this block would be more expensive than building a 383 out of a junkyard 350 block. It seems to me that this block only needs sonic checked, and if it does have enough wall thickness, talk to a machinist and see if it would need a sleeve. Sleeves are perfectly acceptable, that is how all aluminum blocks are made.
If he sells this and has to use a different block, he will still need it cleaned, bored decked, decked line honed, and the list goes on.
Not to mention this one has billet main caps, which fixes (well, it helps) the weakness on a 400 block.

You also can not think that using this block is shaky just because it is .060 over, because of core shift you can have a .060 block that has better cylinder walls than a .030 block, you just need to have the block sonic checked before boring, or in the case of a used block like this, then before assembling.
My advice would be, do not plan on using this block until you have it sonic checked. I agree that using this as is would be a shaky build, but if you have it checked and it has enough wall thickness, then this is a GREAT block to start with.

 

Based on the OP's previous statement:

A 383 build is NOT recommended.

Street car...

Upgrade from the 305...

Solution - 350.

Least pain, least cost (even less than just completing this 400 shortblock - or a 383 shortblock), more likely to stay together.

 

Ok, I guess I did not completely read his intentions,if he can not afford another junkyard block, a new balanced rotating assembly will be WELL out of his price range, a stock rebuild 350 will be about the best he can do, well, that is if he can afford a core motor and rebuild kit, plus machine work, which is obviously well above the cost of a junkyard block!

 

Great news, all... lol

One of my cousins is a GM trainer at a local college. I drove the block down and talked to him about the situation (he already knew some of the deal).

Looking at it in real person, he said that we could deck the block and take care of some of the chip issue (it needs it as it has used tarnish marks).

Second, we measured the cylinders and found out the block was to be .030 over and wasnt even finished (400 block + .030 overbore = 406.7). This means that not only will that make the chip even smaller, but it will help fit the rotating assembly to the block.

I'm looking for 10ish:1 so on with the build...

(and as a side, I would love to hear how a NEW 350 build would be cheaper than the 406 I already have started?)

 

If you were closer I'd give you a good deal on my current setup... speed-pro hypers on 5.7 forged rods and a nodular crank .010/.010. It is about the cheapest way to get a good long lasting setup.

 

Pretty simple, really.

You've got a BARE block. Needs machine work and everything stuffed in it. Have you priced 400 rotating assemblies? You still need heads as well.

On the other hand:

Find a rebuildable complete 350 for a couple hundred bucks. You can rebuild a street 350 for less than just the 400 rotating assy alone is going to cost you.

 

A new 406 rotating assembly is not enough cheaper than a new 355 a 383 rotating assembly to make it a factor. Now he could use a stock 350 crank and rods to save some coin, but by the time you rework the rods, turn the crank, and have it balanced, I do not think the savings are worth sacrificing 30 or 40 cubic inces, and using 20 year old parts.

Now as far as to use this block or not, if he were to buy a core, have it rebored, and line honed to get it in even near the same shape as this block, he would probabably spend considerably more in the 350 block than what he will spend fixing this one, being that the most machine work this one will need is a sleeve, and I do not believe it will even need that.

Not to mention that this has billet splayed caps, that is worth 500 dollaras alone. now that I know it is only .030 over, I deffinitley recomend this block if he is wise enough to buy a new rotating assembly, which is almost always the best way to build a new motor in my book.

 

And that right now is the plan. Machining this block is going to be relatively free thanks to my cousin. I planned on getting a new balanced rotating assembly (10ish:1 kits run in the 700s), getting heads and other than swapping out my intake, I have just about all I need for the swap.

 

When you are buying your rotating assembly and heads, remember that a 406 makes a lot more compression than a 355, I needed to use a 72cc chamber with flattop pistons, at zero deck height, and still have 10.6:1 compression. So if you need to run a 64 head, you will need dish pistons.

 

We're talking about a street engine here. An upgrade to a 305. You don't have to rework the rods or balance the rotating assembly on a simple 350 refresh. And forget the 383 - same reason (although a 400 rotating assembly will cost more than a 383 rotating assembly).

I'd say you're taking a big chance trying to run that 400, especially if you punch it out another .030".

But, your call.

 

I'm not boring it out another .030. We just found out the engine hasnt been bored to its true .030 overbore and so that's what we'll do once the rotating assembly arrives.

For those still beating the 'build a 350' drum, I'm looking at actual prices for the rotating assemblies and the difference in price between 350/355/406 kits is at most around 200. So the decision comes down to that 200 being able to get a 350 that will be a big enough step up from the 305 considering I do not plan to go to boost or juice. AND the person I am working with on this has worked on GM engines since before I could spell Firebird and he is saying we'll be fine once we deck and finish the cylinders because I'm not running a high compression setup.

 

Why would he bore ir another .030 over, it has fresh bores and the most it would need is one sleeve. You may not have to balance a stock 350 rotating assembly, but it would be VERY unwise not to rework the rods, any basic performance rebuild should include resized rods with ARPs, if not you are asking for trouble.So I deffinitely reccomend using this block.

 

Going more than 4.155" on a factory 400 block should never be done unless you have verified the cylinder wall thickness by sonic testing.

I misunderstood what you were saying about its overbore. So, it is less than 4.155" now? The crosshatch looks like a finish honing, did they only take it to 4.145"?

And, the rotating assembly research I did quickly above assumed the 4.185" bore you originally stated. Piston cost was higher that way. Still, you're looking at over $700 plus freight.

And, you still need heads. And external balance damper and flexplate/flywheel.

If you can live with that, go for it.

 

He previously posted that after further inspection it is only .030 over, which is a 4.155 bore and perfectly acceptable. He also posted that it was a fresh bore, and the only problem seems to be a small chip, which I believe is far above the top ring and will cause no problems.

Some blocks even have valve notches that protrude further into the cylinder than that and cause no problems, but an experienced machinist should be the judge of wether it will need a sleeve to repair that or not.

 

What he said was:

{emphasis added}

Sounds like it was intended to be taken to 4.155", but wasn't finished.

Agreed, many blocks (like my 396) have valve reliefs cut in them in the top of the cylinder. But, they were cast for it, while small blocks weren't.

If you're going to use it, and there is more finish honing to be done, and have it decked after that (the chip won't be that much smaller), take a die grinder and lightly clean up the chip to remove the roughness only. Verify the rings won't come up any higher than the chip, and is should be okay.

 

So now that I am this far.... what heads are a good match for what I am building? I know that 350 heads will fit once we plug the block's steam holes (planning on that anyway for extra wall support).

What would be good heads to match a budget build 406? Thanks.

 

use pro action heads.they flow better than dart heads

 

I agree with importspanker, I just bought a set of RHS pro actions and have been impressed so far, and I believe they are a shade cheaper.

What kind and size of cam do you plan on running?

 

i'm running them on my 406.i used a small domed piston,total seal rings,and the 72cc heads with 2.08 valves.comp cams flat tappet camshaft.i believe 495 lift with 1.6 rockers.plenty of valve to piston clearance.