Sammyboy

iTrader: (9)

Engine displacement=8(pi)*((Bore^2)/4)*stroke.....Thus leaving me with a 4.00" stroke and a 3.9694" piston bore. This project is souly ment for nostalgia purposes....but I needed some imput as far as proper stroke to piston size. What was the original...and what forged parts are available.

z28mccrory

iTrader: (7)

If you absolutely HAD to have that CI, i would probably use a 3.9" stoke and then bore a 6.0 iron block to whatever was required to achieve that exact displacement.

ROCNDAV

iTrader: (100)

Mine is a 3.905 bore and 4.125 stroke. Most people don't like this set up because of the extended stroke (unsquare).

I agree with Z28mcCrory in saying that I would stay with the stock stroke and either get an LS2 (or resleeved LS1) and bore it out to its appropriate bore.

z28mccrory

iTrader: (7)

Not necessarily a stock stroke (3.622), but a 3.9 stroke. It would be big money to get over a 4" bore. A stock LQ9 block could be slightly overbored to 4.0xxx to achieve 396ci exactly i think.

Sammyboy

iTrader: (9)

More than likely I would resleeve....but I wanted to try and avoid any custom machining as far as piston diameter....What do you mean by "unsquare"?

ROCNDAV

iTrader: (100)

If you are going to get it resleeved, you are going to have to have machine work done.

As for squareness, it is often thought as being better to have a bigger bore than stroke. Tons of topics on here if you search.

Sammyboy

iTrader: (9)

ROCNDAV...I just noticed your 396 Lunatic stroker...what pistons/bore/stroke/rods did you end up going with?

ROCNDAV

iTrader: (100)

I purchased the complete rotating ***'y as a kit from Lunati:

http://store.summitracing.com/partde...rsview=sku&Ns=

Stang's Bane

iTrader: (22)

Just take a page from Chevrolet. Build a 402 and call it a 396.

REGALIS

I would say Over and Under square. If you have a square engine your bore and stroke will be the same i.e 4" bore 4" stroke 4/4=1

Oversquare would be when your bore is larger than your stroke.

i.e. LS1 3.62" stroke with a 3.90" bore, or you can determine if you divide the 2 numbers bore over stroke. You must have result larger than 1 to be over
square. 3.90/3.62 = 1.07

Undersquare would be when your bore is smaller than your stroke.

i.e 396 stroked LS1 with a 3.97" bore and a 4" stroke.

3.97/4.00=0.99 Result is smaller than 1 therefore undersquare.

Arthur

Sammyboy

iTrader: (9)

What are the advantages and disadvantages of under and over square.

ATVracr

iTrader: (5)

Erik Koenig built me a 3.9 stroke 4.0 bore 396 Nitrous motor. Works great !!

REGALIS

There really is no power advantage to either design. Where they differ is in how that power is produced. Usually, a 'stroker' (undersquare) makes it's maximum hp/torque #'s at a lower rpm. An oversquare motor of equal displacement can produce the same power, but would require much higher rpm to reach the power band.

Sammyboy

iTrader: (9)

So basically your talking about stoke vs bore....the small the stroke the higher the RPM you can turn due to the decrease piston speed...meaning higher power band, verses a bigger stroker motor.

REGALIS

You bet.

67camaro

iTrader: (28)

Have a machine shop offset-grind the stock crank to a longer stroke and bore a 6.0L iron truck block to get the rest of the cubes.

1Hawk

The closest I think youre gonna get is to use a 5.3 litre block and use a ls1 3.960 piston (which scoggins sells) and a 4 inch bore crank with a 6.125 rod...that make like a 394ci. Or you can go stock bore 6.0 iron block with the same crank and rods as above...thats a 402...But honestly if your gonna spend the money to put a motor in a car i would do something thats gonna make some big power. like an iron block 414 or something...Utilize the new 4.125 and 4.200 cranks in the 6.0 iron block with a common piston like a 4.030

devilsalmostfree

iTrader: (28)

yes you can get a 396ci out of a LS1/6 block
383-4.000 stroke
396-4.125 stroke

99blancoSS

iTrader: (115)

4.135 bore x 4.250 stroke and 7300 rpm limit. big stroke big rpms need air

GrannySShifting

iTrader: (10)

Just use a iron block, with a 3.9 crank, its standard parts no real funky stuff. He did ATVRacers motor about 3 years ago.