Why not find and build a 400 ? I know I can do a 383 but whats the deal with the Chevy 400 ? Bad choice ?

 

Build the 400 and don't look back. I've never understood the 383 craze myself.

I usually catch a bit of you know what for this, but get a four bolt block. When I used to race them back in the late 80's every two bolt bloct would lose the main bearings because the caps walk under full load. A couple of limitations with the factory blocks is you can't bore them much. 0.040" is the max I've been able to go. Additionally, the bottom end doesn't like a ton of RPM, maybe 7000. I never had a problem with one, but they will break under enough stress. If you are going to be in the 550 hp range or run nitrous or something; look at an SHP block. In fact, I've seen SHP short blocks that are so well priced, it would be hard to justify buying all the components, doing the machine work, and building it yourself.

If you decide yo build your own, there's several other peculiarites to them like absolutely using a deck plate, external balance, rod length, steam holes, possible rod/cam interference, etc. That you need to understand.
.
Oh, and a well thought out 400 build will trounce the 60's BBC's

 

400 blocks seem to be a crap shoot some times, I have seen a bunch that did not sonic test very well, Crack between the head bolt hole and cylinder when the torque plat is installed making the block junk!! But the customer is always warned and unfortunaly has to pay for sonic testing, clean, mag, decking, bore and hone.

Here is an interesting thread on a 400 block that eneded up junk but he was warned!!!!

http://www.stevesnovasite.com/forums...d.php?t=185248

 

I come from the Pontiac world where the 400 is the base choice....not a 350. So it seems the Chevy 400 is not considered a safe choice for a "spirited" build ? The 350 is a safer cheaper way to go ? The SHP blocks look like they start at around 1600.00 I should be able to build a 383 shortblock for that much easy, right ?

 

Building a 383 for 1600$ would be tough. I've got roughly 10,000$ into my shp 400, could easily come real close to that if I had built a 383. I would guess it would depend on what ya already have for parts and how well you know the machinist at the local machine shop. The local machine shop here in anchorage told me it would be wiser for either a 383 or 400 to go with a new block instead of a 30 year or so old block. This is something I've always wanted to do & I might not get thee chance to do it again so I took his advice.

 

Factory 400 blocks that haven't already been cut are getting hard to find, and they're generally poor castings.

The appeal of a 383 is simply that it can be built from virtually any factory 350 block - simple and cheap. An aftermarket cast-crank, hypereutectic piston 383 making around 400 HP can be built for less than 5K with the right foundation and smart planning. The best foundation in that power/price range is a factory Vortec roller engine.

If you want more power or if you plan to user power-adders, then it's a different discussion.

 

Last time i looked there were several 400" engines at Ecology auto parts (pick your own yard) - for $200 come and get it. BTW the bone yards guarantee the block is usable or money back. I really stopped looking for blocks because i don't have the garage space right now - with a GEN II block on the on the engine stand. Well last summer (2011) i saw the same guy/vendor from AZ selling bare blocks at the Pamona swapmeet in LA as he has for years and he still had 400" bare blocks cleaned and oiled for inspection - high nickle too - 'bout $400 i remember. If u want PM me and i'll try and find his card.
Have u tried to look for a 400" block? Many times u will find them in running cars like station wagons and blazers where u have to buy the entire junker to get the motor. But yes if u call the bone yards they may not have many running cores for sale these days but once u really start to look for a 400" in like craigs list and other local classified's u shouldn't have much of a problem. Yes there are bad blocks out there. I saw a bare block at Long Beach swapmeet completely covered in orange rust - seller somehow thought i was protecting the block. If your really worried of bad blocks GM has a brand new 383" ready block, try scroggin dickey <$900: http://sdparts.com/details/gm-perfor...8962516.:cool:
I guess from your first question there are just a few techniques that differ for a 400" block build - but a D. Vizard book for <$20 covers them all. Due to just the size the 400" block should make more torque and hp than a 383 - no clearancing for the rods either. Yes there are a few techniques/operations needed to prep the 383" motor block also.

Let me know if i can help,
cardo0

 

From my under standing the 509 2bolt casting is stronger. Even if the vendor will refund your money on a bad block don't cover cost of having it sonic tested.

 

I'm not looking for over the top power. I think I'll stick with a 383 to keep things simple. I was planning on buying a kit and installing it myself. I got a good 350 block already. I'm trying to decide if I'll use the "racer" machine shop or the "builder" shop....

What special block prep would I need for a tiny bit of boost ? Like under 100 shot of nos ? Would I need 4 bolt caps for that ? The rest is tolerances right ? Good pistons and rings ?

We are talking short block here. If I can build one for a little less than I can just buy one I'll do it. I feel like messing with an engine project.

 

Nitrous kits at or under a 100hp are designed for stock engines but since your building from scratch get forged pistons and good rings,4 bolt main is not nesseary but get new main bolts or studs. You should be able to buy a good set of rods for less than rebuilding stock ones.I always have blocks "race" prepped but if your on a low budget bore and torque plate hone will get you by just make sure the block is checked. Nitrous can get addicting so build it for more than "just 100 shot". Your fuel system will be very important for higher hp levels.

 

400's bigger bore breathes (fills cylinder) better than 350's smaller bore ... bigger bore wall is further away from valves.

suggest boltnut list approximate geographic location in profile ... could be someone nearby has what he wants? ... this time ... or in future.

 

A race shop will surlely do a better job as I see what the local jobber shops do for work, Boring off unsquared decks, no balancing, no torque plate honing which is a must for good ring seal, I also line hone every block as I find GM main lines after many heat cycles they are not very straight.

Having a known deck hight to achieve a .040 to .050 quench is a must as it will be less prone to detonation.

If you want a so so job go to local jobber shop and roll the dice.

 

The minute you start thinking about power-adders then you should step up to an all-forged ***'y at the very least, which changes the numbers a fair bit. Same regarding 2-bolt block, I would step up to a 4-bolt. Don't get caught up in "I have a block"...you'll be spending some serious machine work dollars here, so don't start with the wrong foundation and spend a bunch of money trying to get it right. But a factory roller-cam, 4-bolt block is fine for the power levels you're looking at.

It will always be cheaper and easier to buy vs. build. In the end, the only money you're "saving" is on final ***'y. But there's nothing like building your own engine, if you have the patience and are willing to learn the skills to do it

My views on racing vs. just a good, solid machine shop are well-known on here, but you don't need $4,000 of machine work on a $3,500 block for an engine making < 1.4 HP/CID. Get performance references from both shops and make your decision based on that - there are good/bad shops everywhere, regardless of the type of work they do.

 

To machine an OEM block correctly Sonic test, clean and mag, line hone, square a deck to zero, bore and plate hone to finish size, stroker clearance if needed, lite hone on the lifter bores. Most good shops are under 600.00 and thats far from 4000.00 on a stock block

I see to many guys cut corners on block machining and it some times will bit them back with blowby issues, bearing issues, oil pressure problems ETC. just do a search on these problems!!

If you need the VIN numbers left on the deck and the shop can't do that its not much of a shop and you should find one that can deck the block and do it right!!!!!

 

So that's what you charge on your CNC machine? I pay about $750 for that package at my shop.

 

750.00 is way to much and can your shop leave the VIN numbers on the deck???? I would be under 600.00 as most good shops would be as well

 

John Lingenfelter the original was a huge fan of the 400 and debunked all the myths about 400 small blocks in his book John Lingenfelter on modifying small-block chevy engines. It is a older book but almost all of the information still very very good. I am pretty sure it is still available. I personally have a worked 400 in my 79 and love it.

 

Machine work prices vary a fair bit geographically. My experience is that it's a pretty competetive price; I'd be interested in what others are paying for block machine work; that $750 includes:

* Clean/mag/sonic
* Mainline hone
* Surface/cut deck as req'd or to spec
* Bore/hone with plates
* Stroker clearance
* Install cam bearings and final block prep (plugs, pins, etc.)
* Hanging the pistons for pressed pins.

I get the block ready to clean, check and assemble.

ANY decent shop can leave the VIN - it's not magic, and shops were doing it a couple of decades before CNC was generally available. Folks that get their VIN cut are ones that don't correctly review this with the machine shop beforehand.

 

The shop you use what do they deck with to leave the numbers on the decks or do they deck the block and take the numbers off?

 

It sounds more like u want the experience of the entire process rather than buy a finished block. Well in that case your known good core 350 block is as good as any and can't beat that price. D. Vizard has some great "How To" books on building sb chevys but i recall there are books now on just building stroker sb chevys. U will need to know where to clearance the block on the pan rail and how much. U can also buy special bolts or grind the the rods bolts to help clearance too.

I just suggested the GMPP 383" bare block as all the plate honing and rod clearancing is already done. But u really need a 3.8" stroke crank for that block and u can only purchase that size crank as forged - $600 minimum. Also u need special sized pistons that GM uses for the ZZ383 engine though u may find them elsewhere. Just posting this so u now whats out there.

I know nothing 'bout NOx and can't help u there but suspect a forged crankshaft a minimum for that.

Good luck and post your results,
cardo0