Lateral-g Forums - Stock SBC block w/ 4" stroke?

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Quote:

Originally Posted by Scotch

I get it. While I appreciate your angle, the capabilities of the big-inch small-block crate engines out there serve the need. Otherwise, if you really want to build this within the confines of a stock small-block, there's plenty of potential in a 406 to make the kind of power you're looking at.

The thing is...once you decide to go after that other 40-50ci, you really want the raised cam/taller deck to make it work for you. You need to give that crank room to swing and you want to run good connecting rods, and they need clearance too! You don't want to be grinding the rod bolts down or notching the bottom of the cylinder bores if you don't have to. To get a bunch of stroke into a stock block would require these kind of clearancing techniques and while they've been done before, they are also the reason the aftermarket tall-deck/raised cam blocks were engineered in the first place!

So, I'd have to recommend either a very serious 406 or an aftermarket block-based 450-ish inch setup. Based on what I know, which ain't as much as lots of other guys, but is a little more than most, building torque will not be your challenge here. Putting it to the ground will be. I think if you've got 500-550 ft-lbs being put down without tire spin, you will be a happy guy. You can make that kind of power with a very serious 383 or a very good 406. A mild aftermarket block-based 450-plus inch SBC can do even better at lower rpm.

~SP~

Thanks SP,

You nailed the requirements above dead on. I guess I should have said "I want 400 ci w/o a bore bigger than 4.060". I looked at my cylinder heads again and if I were to use a 400 block, the cylinder bore and bore centers would be all wrong for the heads and the head gaskets. (Don't ask me to explain; just take my word for it :_paranoid ) I already have a stock block so I was looking at 396 and 401 combos w/ a 3.875 stroke or just maybe a 402 w/ a 4" stroke. Oh well 383 it is for now. :mad:

Thanks again guys for the help.

Mal

Save yourself the headache and block clearancing and build an awesome little 406 with a 3.75 crank and go woth 6" rods trust me will be all you will want to handle if you can hook it up! ecs mated with a good set of heads 215cc would be just right, this is the exact combo im building for my prostreet keep your cam under 270 ish @.050 with a good single plane and you will A. save your self the price and headache of clearancing your motor and B. will most likely out perform the set up you mentioned beacause increasing the bore to 4.0 will indead at torque but like mentoned not with out problems with cam clearnace etc

In the fall issue of Chevelle by super chevy the is an article on a 408 chevy that is a stock block with a 4" crank by T&L Engines ( tandlengines.com )

They can go up to 414 on a stock 350 type GM block. Heres their spec sheet. Not bad for under 5K

408 Chevy A-2 510 HP 500 Torque - $4784
•
4.00 stroke 4340 forged steel crank
• 4340 6” H-beam rods
• Mahle forged pistons
• Mahle file fit rings
• GM 4 bolt block
• Dura-bond cam bearings
• Block plug kit
• Oil filter adapter
• Hydraulic roller cam
• Roller timing set
• Custom gasket set
• Chrome timing cover
• Professional products balancer
• Balancer bolt
• Melling high volume oil pump
• Melling oil pump drive shaft
• Melling oil pump pickup
• Hydraulic roller lifters
• Dart or RHS aluminum heads
• 7/16 screw in rocker stud
• Comp cam push rod
• Aluminum roller rockers
• Edelbrock RPM Air Gap manifold
• ARP head bolts
• Chrome valve covers
• Chrome oil pan
• Autolite spark plugs
• Oil filter
• 12 pt bolt kit

Labor

• All parts hand cleaned
• Block sonic checked for thickness
• Block pressure tested @40 psi
• Block stroker clearanced
• Block square decked w/BHJ fixturing
• Aligned hone mains
• Bored and honed w/torque plates
• All clearances checked to the nearest .0001”
• Rotating assembly balanced
• Engine blueprinted w/specs sheet on file
• Engine fully assembled and dressed to customer specifications
• Dyno tested

Blessings,

Here's a picture of what the dart alum. block is notched from the factory and it clears my 4" stroke, 6" rod combo (callies crank/rods) just to give you some idea of packaging. You will need a pan with notches too unless you want to get real creative. (pan spacer, etc.)

It does raise a lot of 'why' questions though on the 350 block-- there is a lot of HP to be gained by that extra 1/8" of bore, not just cubic inches, but in unshrouding the valves. One of the reasons why '358' cid busch/cup motors are big bore, short stroke.

Quote:

Originally Posted by R67Chevelle

Hey thanks,

I'll look that issue up for some more details. I knew I was not crazy :willy: when I saw all of World's block specs had stock deck heights but stated they accpeted 4" cranks! Now I have to ponder a decision again 383 or 400? :_paranoid

On another note 67Chevelle I sent you a PM. Did you see it?

Mal

You might want to check out this book. I found it very useful in helping me decide how to proceed with a big-inch small block that I wanted to build.

http://www.cartechbooks.com/vstore/s..._ID=3166&DID=6

are you still working on this engine build 4ofakind, if so would you have pics.

i have a 400sbc(509#block) that i plan on putting a 3.800'' crank in it. i also plan on having it filled half way with block filler.

good luck with your build

Very few racers use a stock block unless its a stock type class, all Modified, late model, bracket racers all use aftermarket blocks, many of the street engines I build are aftermarket blocks.

Quote:

Originally Posted by XTRMEASURES

Thanks xtream,

I was just thinking out loud as I plan my motor direction. I have a 350 2bolt block sitting in my garage waiting for me to get done mounting my body so I can locate my engine and trans mounts and start rebuilding the engine.

I just bought a 4L80e last week. After Christmas the car will go in the shop to get body, engine, and trans mounts. Then I have to buy a set of cylinder heads. Engine rebuild will probably start in June. I'm leaning toward a 383, but I won't rule out a 3.875" Stroke w/ a 4.060" bore for a 401ci displacement. Check back then. I will have lots of pics.

Mal

Quote:

Originally Posted by XTRMEASURES

I have a 400-509 casting block also and was just going to do the same as you but with the standard 3.75 crank. topped with the dart iron eagle heads I already have, a victor jr. and my demon 750 and stab it with a solid roller lunati. and try for somewhere around 10.5-11:1 comp. gotta love 93 octane..