how is running a 396 on the street any worse than a 383? you add a little bit to the crank and nothing to the bore, so your not getting any thinnner in the cylinder walls. the only advantage i know of running a 383 over a 396 is the mystical rod/stroke ratio that really doesnt mean squat in the overall picture.

the KISS philosophy works best for street cars IMO. thats Keep It Simple Stupid

 

Lol....sorry, go to http://web.camaross.com/forums/index.php? and search there. I remember one or two threads on a 421....more threads on 409's....matter of fact, here's a link already searched out for ya.

http://web.camaross.com/forums/searc...earchid=537632

 

These arent really stroker kits persay, a lot of it is how much you bore the block with a certain stroke crank to achieve the cube numbers. I personaly would never want to go that big when a built 383 with a great set of heads can do the job for most aplications.

 

Ghost your link doesnt work. well not for me anyway.

i agree with Bizzzatch. honestly the only reason I am considering a 396 is itll bring the torque curve down a little more which better suits my application and it just sounds cooler. aside from that a 383 is a great design. just look at how many 383 Gen Is there are and how much power they are making. want to squash a big block? build a stroker small block.

 

Amen to that...

 

The cylinder walls are not the issue.

You have to grind the lower end more for the larger stroke crank to swing. Some blocks are thin in these areas and will crack into the water jacket after they run for a while, ruining all your high dollar machine work. The chance of that happening is less with the smaller stroke. So why risk it? The power difference is no where near risking this senario. 9 1/2 out of 10 people either cant afford or dont know how to feed even a 383 correctly to make the kind of power it is capable of making, so why a 396, 410 or 421?

Torque curve is dictated more by camshaft and cylinder head port cc if fed correctly, sure the torque and power curve will move down on a 396 vs 383 only because you dont have enough cylinder head on it. No one one earth can stand behind and engine and tell you how many cubes it is by listening to it.



David

 

good point i had forgotten about the clearencing on the bottom of the block for the crank throws.

and your right the cam and heads will better dictate the power band which is why so many 355s beat up on 383s. i say if your stroking a motor you need at least LT4 style heads.

 

Yup I researched Strokers alot. going over a 383 with out a NASTY set of after market heads is Usless.

Most heads peak to early on a stroker. it takes ALOT of welding and porting to get a LT1 head to flow the correct Volume and Velocity to make power with a stroker.

The cheap way to make power is with a forged 355-366 combo. A set of ported heads will feed that to 7,000 just about any time

 

Sorry.. thanks for help guys

 

Ellis, how do you build a 366? i have never heard of that displacement

 

Not one to call the BS flag but, in order to get even 650rwhp assuming an 18% drivetrain loss the cylinder heads would need to flow over 355cfm. Unless your guy has a set of worked 18* or SB2.2 heads on it, it ain't happnin'. Not all motor anyway. I'm trying for 750 at the crank with this LT1:

 

Agreed. With a 383 you would need at MINIMUM a set of hogged out GM LT4 castings. I talked to a few guys a G9 this weekend with strokers and all were running ported stock castings. I guess for budget constraints. This is why you see so many stroker LT1s in the 430 or less RWHP. Its pretty pointless to go stroker if you're going to do that.

 

Bringing this bitch back from the dead!

Love those cup sb2.2s, found your other thread mentioning they flow 379/260. Vicious.

I've been reading old threads from 04-07 all day about 408, 410 and 421 lt1s and wondering if anybody still knows of an active one other than Joel? Jason Short built a couple, and I found some threads about fitting a 4.125" crank in there to make a 421-427, anyone have a part number or any info on a set of rods with a small enough big end to clear the cam without having to go to less than a .9 cam?

And yes I am just dreaming, but I realize you would need done sb2.2s flowing 370+ cfm to make this worth it.

 

If you're looking into stroker LT1's and since you are in the area call Burtonsville Performance and Machine in Laurel, MD. They have been doing LTx and LSx engines for at least 10 years now. They aren't cheap, but build quality blocks. They'll tell you what time it is.

 

I have a 95 Corvette block and stock I used an ultrasonic on the walls. I had .140" thickness between cylinders and .240" the other directions. About .040" over for ~.100" wall thickness is my limit but others have gone to a .060" over. You can't reliably go over .060" for long, but possibly with an hardblok filled engine you could. So with that limit you have to chase stroke, that means you need to to get to a 4.0 stroke crank at minimum.

I put a 3.875 stroke crank in an LT1, it took a bit of clearancing, but there was room for a 4.000" in crank like some run. Probably would need to fill the block as clearancing the bottom of the cylinder would hit the water passages.

To get above 3.875" stroke the following is a must.

Connecting rods:
Bolt heads may have to be machined to be shorter.
May have to buy bolts with a smaller head (ARP2000)
Shoulder of connecting rod may have to be massaged to clear the camshaft lobes

Pistons:
Piston skirt may have to be massaged for the crank clearance.

Camshaft:
If the rods don't come close enough to clearing or you have too much lift on the camshaft you will have to get a smaller base circle camshaft.

Block:
Bottom of the cylinders for the connecting rods.
Oil pan rails for the connecting rods

Oil Pan:
Going to be doing some beating with a hammer on the scraper or grinding.


4.060" Bore x 4.00" Stroke 414ci
4.070" Bore x 4.00" Stroke 416ci
4.070" Bore x 4.05" Stroke 421ci
4.070" Bore x 4.10" Stroke 427ci

Most of that would be custom pistons and crank, costing lots of money. I wouldn't bet that the engine would last a season, especially if you are spinning the hell out of it.

 

4.070 is not in my mind worth it. The builds I've seen on the interestnet today mentioned 2-3 that stuffed a 4.125" off the shelf crank in there, but yes you are chasing stroke. Enough people have run 4.060 bores for long periods without issue. Joel's 414 is still humming along begging for some 13 degree heads.

I agree with all the clearance points you mentioned, but I don't think it all has to be custom. Yes you need clearances rods but there are plenty of off the shelf scat, Callie's, Oliver and lunati rods that will work with a 4" crank, the question is will the extra .0625" of length be too much and hit the cam with a 4.125" crank.

The 427 I was mentioning was 4.060x4.125

 

Mark Montalvo did it years ago with GTP. In fact it was in an old 1996 GM High Tech Performance mag. I might still have it.

 

A 427? time to dig through google...

*edit* looks like guys have been grinding cranks down to 1.88 journal like they do in nascar and having plenty of room to clear 434s in SBCs. So looks like a 4.125" crank will fit if you go down to a 1.88 journal and use Acura bearings.

 

less cubes and rev it to oblivion

a 385 @ 8krpm pulls in far more cfm than a 427 at 6000..........

im still trying to figure out why everybody in here is so hell bent on building motors with massive strokes and no bore....espically when 99.9% of them cant get enough air through the heads into them anyway

 

I personally would have loved to have extracted 421 cubic inches from my LT / SBC engine - as my first real love was my 1966 2+2 with a REAL 421 from Pontiac (R.I.P.), which I thought was quite great; however, reality sunk in and after doing the math and speaking at length with my builder, we settled on a 383 - 38 cubes / 10% shy of the original target, but a (as stated above) a lot safer.