LD85

I had planned on stroking my 1985 Vette to 383 w/Scat 9000 crank, & stock 5.7 rods and D-port heads.

I can pick up a 2-bolt main, casting #3951509 standard bore 400 block with some wear, for $225 for the block, crank, and 5.565 rods and bore it to 406. I could have the 400 splayed I guess if necessary.

Will the distributor, and damper etc swap out from my 350 to the 406? Any major issues?

Intake, cam and headers and 113 D-port heads with 2.0 & 1.6 valves would all be equal being a Stealth Ram preferably after making my own plenum or a Superram. At the least a major port job on the stock plenum and large tube runners and a new base.

I m not building a monster thumper but would like a potent ride!
High 12's or very low 13.s

Help me before I go crazy, this thinking so much about how to build this motor is making me nutso! :cry :boxing :crazy:




[Modified by ld85, 3:28 AM 11/13/2002]

ol,RJ

well a 383 will probably be cheaper to build (but the price for that 400 block is hard to beat).
a 406ci is just a 400 block with .030" overbore (not stroked) (btw .030" over is max reccomended on a stock GM 400 block, aftermarket is different).
both the 383 and the 400 will need a new balancer (get the small one so it clears the crossmember) and flywheel (this can be tough to find because you need the small 153 tooth one to fit in the stock bellhousing). the best bet is to buy a kit (rotating assembly with balancer and flywheel, and have it balanced together).
the 400 block has steam holes that have to be drilled into the heads for proper cooling, and the oil pump shaft must be the necked down version (most aftermarket one's are this way already) for clearance (the 383 should get this shaft too I think). everything else should interchange.

as far as which one should you go for, depends on your budget. better heads would be nice, especially on the 406. same for the intake/ exhaust system.

oh, figure up what you think it will cost, then double it. that might be close to what you'll spend. :yesnod:


[Modified by ol,RJ, 3:01 AM 11/13/2002]

Jimbo93

I'd go with a 383 with 4 bolt main. I wouldn't trust a 2 bolt main.

atotalnincompoop

i had a 383 and smoked it this summer, now i'm running a 30 over 350, and planning my next one. I had seriously considered a big block but have decided on a 400 based smallie. I'm probably going to build a 420+ inch stroker, there is no replacement for displacement. :cheers:

Nathan Plemons

Why not compromise and make a 396?

You can do that using a stock 350 block and you wouldn't have the some of the problems that the 400 block had. If memory serves people here claim that they had overheating problems and such. A 396 is just a 4.030 bore with a 3.875 stroke.

The longer 3.875 stroke as opposed to the 400's 3.75 could give you more torque out of the original block. Problem is that if you're wanting to do it on a budget it's probably not possible. I've never seen a 396 crank that wasn't forged.

vader86

The overheating problems with 400+ engines is a direct result of poor build quality by whomever built that engine. Properly built, with the correct steam holes drilled, it would not overheat.

I would go with 383, because of demand the parts are cheaper, and you can afford to go forged all the way. 396 is also a good compromise.

But i would be more worried that the D-ports would be unadequate to feed a 396 or bigger engine.

Nathan Plemons

A very valid concern. Also make a note however, if you can afford to do a forged 383 than you can afford a forged 396. The difference is crank price is minimal once you're forged. Block clearancing will have to be done for either a 383 or 396 so that should be a major issue either.

BLUE ONE

If you "only" want high 12's low 13's you don't need a stroker at all :smash:

You can do that easy on a 350 with intake, head, cam and exhaust mods :yesnod:

:cheers:

HWoods

There is no substitute for cubic inches. If you can get ahold of lingenfelter's book on small block chevy's it has a small article about a 406 and the torque monster it can be. You can build a very stout engine that will make tons of HP and torque below 5500 rpm, so you will not need forged a crank. ck out http://www.allchevyengines.com too. They have one there. You may need to still use a small base circle cam if you go with 5.7 or 6" rods. But the 406 is a good choice.
From allchevy engines web site:>"400 GM 2 bolt block
New Elgin "cast steel" 400 crank (std,std)
Stage 3 superstock 5.7 rods with ARP "wavelock" rod bolts
Hypereutectic flatop pistons (10.3:1 comp)
Sealed Power rings
Hydraulic flat tappet camshaft (.500 lift,292 duration)
Heavy duty Cloyes timing set
Michigan 77 bearings
High volume oil pump
Fel-Pro gaskets
World Products "Dart II Sportsman" heads
Hard seats and guides for unleaded or reg fuel
New 2.02" stainless intake valves
New 1.60" stainless exhaust valves
Screw in studs and guide plates
New Crane dual springs
New chrome moly pushrods
Crane roller rockers
New oil pan, timing cover and chrome valve covers
New GM harmonic balancer damper
New heavy duty flexplate (std trans flywheel extra)
Edelbrock Victor Jr manifold
Balanced, blueprinted, assembled and painted
only $3499 "


[Modified by HWoods, 12:56 PM 11/13/2002]

ASRoff

In the Imortal words of smoky yunick "put in the biggest damn rod you can find that will fit in the block" :D

LD85

Spoke with my builder today, he said that the 400 is OK but some parts like a flywheel can be a little more expensive and some parts harder to find . He said that the heat issue is negligible if steam holes are put into the heads but it will run a few degrees hotter.

On splaying from 2-bolt 400 to 4-bolt he said that this weakens the web and that the only way to do this is to put strap from one side of the block to the other, not cheap.

He said that use 2-bolt mains all the time for and they work fine up to a point/RPM. He would use the 5.7 rods in the 400 and go with a dished piston depending on the head CC to end up around 10:1

He likes the 350 / stroker cause of parts availablilty and cost. He says no need for a steel crank unless it is going to be abused on a regular basis. He also said of all the hundreds of motors they have built they have never seen a cast crank break. He has seen crank bearing issues but never a broken cast crank.

Regarding the D-ports TPIS says theirs flow 260 CFM at .610 lift and Lingefelter and TPIS thinks enough of the D-ports to sell them for a lot of money so IMO, with good porting and polishing they can be plenty of head.

Also in Lingefelters book he uses the D-port on a couple of 400+ HP motors with his Superram.

Info from Scat web site:
"You've heard of a crankshaft referred to as a casting, a forging, or a billet, but what does that mean, what are the differences between them, and what is the strength comparison? Basically, a cast crank is made by pouring molten iron into a sand mold, letting it cool, than pulling it out and machining it. This is the easiest and least expensive way to make a crank, and that's why the majority of stock cranks are castings. They are strong enough for most stock applications, and will run forever in a daily driver. But bolt a blower or nitrous system on the engine, and start making some power, and a stock cast crank is living on borrowed time. Scat has a line of cast cranks, the 9000 Series, that are available in several different strokes and are stronger than stock. Lieb told us that the tensile strength of a stock cast crank is 95,000 pounds, whereas the 9000 Series cast crank is rated at 105,000 pounds.

A forged crankshaft is made by taking a big piece of iron and forcing it into roughly the correct shape for a crankshaft. This obviously requires mammoth machines, which dramatically drives up the cost of manufacturing. The advantage of a forging over a cast crank is strength. The material used for a forging is generally better to begin with, and by moving the metal instead of melting it, the grain structure of a forging is better. Pushing the metal around does not break the grain structure, it just stretches it into a different shape (think Play-Doh), and that promotes greater strength. Among forgings, there are several different materials used to make cranks.

A production forging is made of 1045 carbon steel, which has a tensile strength of 105,000 pounds (the same as Scat's 9000 Series cast crank). The next step up the ladder is 5140 steel, which has a strength of 115,000 pounds, and 4130 with 120,000 pounds tensile strength. The strongest forging is 4340, which has a strength of 140,000 pounds. The biggest differences in these types of metal is the grain structure, (which is what holds the material together), the heat-treating process, and the actual mixture of the elements. For instance, 4130 and 4340 steel have more chrome and nickel in them, which increases strength.

Crankshaft durability is measured in tensile strength and fatigue strength. Tensile strength is measure when a 1-inch-round piece of the metal is put into a fixture that tries to pull it apart. The force required to break the metal sample is the tensile strength. Fatigue strength can be best described by thinking of a piece of tin. You can bend it back and forth for awhile, but it will eventually break. The crank goes through the same type of bending and twisting, from cylinder pressures, vibration, block distortion, high-rpm clutch launches and stuff like that. As tensile strength goes up, so does fatigue strength."

What I have learned from the CF is that you can take a 383 and have real good heads and cam and a stock ported top side and go to low 12's to high 11's like HOLESHOT does.

I am so confused that I am ready to blow a gasket myself, info overload to the max! :crazy: :crazy: :crazy: :crazy:

Oh yeah thanks for all the opinions I truly appreciate thinking about all the different options and reading all of the discussions!

Links to engine combos: http://www.geocities.com/MotorCity/7610/dyno.htm




[Modified by ld85, 5:13 PM 11/13/2002]

Ken Lanham

Here is one other option to really get your heads spinning. This is one that I like alot. Use the 400 block, it is plenty strong enough, even though it is a 2 bolt main. You will have to do the mentioned mods to the heads, and proper block machining. Then buy a good used FORGED aka STEEL 350 crank. They came in many cars, like Corvettes for instance. They are much cheaper than any of the fore mentioned aftermarket peices, and are quite strong. Even after a nice clean up on the journals and balancing you come out ahead. You can use a 5.7" or 6.0" rod, whatever you choose. I think SRP, the off the shelf division of JE, makes a piston that will work with either rod length. Then you can use the common 350 flywheel and balancers. You will end up with 377 cubic inches + or - some depending on the final bore dimension. The 400 block will certainly live to much higher horsepower with a lighter crank in it. The forged crank also won't flex as much so will probably contribute to the block and bearing longevity. Also, the bigger bore will unshroud the valves a bit, allowing the heads to breathe better. Seems like a winner to me. It will just require some junkyard hunting for the parts. I can get a block and crank for less than $100 around here if you are willing to look. But I'm kindof a junkyard rat.

The above is based on my research, I haven't actually built this motor. So don't take anything as fact without further research. But, I think I am on target here. Just another way to skin the cat.

-Ken
Englewood, CO :smash:

ol,RJ

sounds like you've been doing your homework!
nothing wrong with going 406ci (thats what I'm running!!).
If your willing to spend the cash then its a "no brainer" go with the cube's.
you will need some good flowing heads "stock" D ports are not going to cut it, ported one's might do the job but for the cost of serious porting you could buy aftermarket. I'm running AFR 210's (ported) but you could settle for their 195's or go with another company and get something around 200cc.
I had the AFR 195's on mine and made 380rwtq, 350rwhp. with the 210's its making 410rwtq and 416rwhp (nothing but the head's changed, and some porting).

I'll take you a ride in mine, that will make a believer out of you.


[Modified by ol,RJ, 1:28 AM 11/14/2002]

CORKVETTE1

400 here :cheers:

LD85

OK so a 406 it is! :yesnod:

Wont be anything fancy but even mild it has to be a lot stronger than a stock 1985 350-230 HP L-98. ;)

FYI, this 509 block is out of a truck. :cheers: :cool:

AquaMetallic94LT1

I recommend the 400 block as well. The larger bore 4.15 will give the engine better breathing than a 4.060. Cast crank will work fine. Fel pro makes some new gaskets for the 400 that are supposed to help with the cooling issues.

You could use a main girdle for strength on the mains. Ford guys use them on their small blocks. Honda motors also have them and Honda engines are very well engineered. They are not as common on Chevy but would definitely help with rigidity.

Ken Lanham

If you use the 400 crank, are there some special flywheel and harmonic balancers that need to be sourced to make the motor work in a Corvette? Either with a Manual or Automatic?

ol,RJ

Ken,
the 400 crankshaft is externally balanced (older 350's are internally balanced) later model 350's are externally balanced too but that doesn't mean they'll (flywheel,flexplate,damper) work on a 400. the rotating mass is different between the two.
the whole assembly should be taken to a good shop and balanced so you'll know that they'll work right.

I just thought of another part that is different. the oil pan and dipstick! they are on the other side of the motor.
RJ

LD85

Ol RJ: What heads do you have on your motor? Looks liek this deal will be going through for me picking up the 400.

I am selling the D-port herads and will go with a head that will breath a little better. My stock 85's are proabably better than the D-ports for this engine. being 76CC and already having 2.0 and 1.6 valves in the 624 head.

ol,RJ

the heads I'm running now are "AFR210's competition ported"
my old head's were AFR195's (not ported) they may be more what you will want for street use, mainly because of port size, the 195's still take a bigger intake gasket "fel-pro #1204" but most intakes can be ported to this size. the 210's take an even bigger gasket and the exhaust port is bigger as well (my 1and3/4" headers are just big enough).