Here is the the idea let me know what you think block will either be ls2/lq4 for stoke could use a 3.825 crank and stock bore which will give me 384 Cubic inch.Or could use 3.825 crank and bore block .030 which would give me 390.32 cubic inch let me know what you think.

 

Seems silly not to use a 4.000" stroke crank which are most of the time cheaper and have the benefit of more cubic inches obviously... Unless you are building an engine to fit into some class rules.

 

I just thought of this and figured i would get some feedback since callies has there ls series cranks the 3.825 crank is 569.00 and so is the 4.000 crank i just liked the idea of a little shorter crank than 4.000 390 is not a real common cubic inch for an LS atleats i dont see alot plus i think it might get a little more longevity out of it because it is a real mild set up.Thanks for the input.

 

They do make that one. I don't know what pistons it uses though? It should work fine but the piston selection may be lower than normal.

 

Maybe they do have some stuff for this stroke as why else would they have it? I saw it but haven't thought about it much as I am so busy but they must have something for it?

 

It's far from real mild. It opens doors to pretty wild. A super nice ring pack for street or race or both, reduces side skirt loading as per piston design, less restrictive on cam size and rod brand usage.

Go for it!

 

I still think its worth looking into, would like to see something out there with one of these cranks. Piston choice is probably limited or non existent though like Erik said unless its custom of course.

 

i would not use a 4inch stroke with a iron block. unless you want it to SUCK
OIL. IMO

 

Anyone know what pistons i would need for this.One of the reasons for this stroke is also to see if this stroke would reduce the issue i have heard with some 4.000 stroke iron blocks are having with oil consumption

 

A lot of people barely know what they are doing. We've been doing 4 inch strokes for almost 10 years and don't seem to have all these "issues" really? Most are the usual problems with people not venting the crankcase or not using sealer on the rocker studs etc. or using pistons that are not designed correctly.

 

Silly?

You can use a 1.220" CH piston, lot thicker then whats used with a 4.000" stroke. We've seen 408 boost pistons come in with lifted top ring land tweeked and peeled over, cracked in the valve pocket to the top ring groove, in some cases people may have not noticed the drop in compression.

I'd advocate the use of 3.825 crankshaft and I think its better combination for boosted engine with the right piston vs. the usual 1.110" stuff.

Fraser

 

Which 1.220 pistons are you referring to Fraser? I wouldn't mind a taller piston for big blowers but that is already a 5140 crank and not a 4340 so it wasn't aimed at big power adders really. I can make a custom piston like we do every week but then that 3.825 crank really got expensive. Plus we already have 8 second 4000 pound trucks and those 1.115 pistons seem to hang in there with the right tuning. I agree though that 1.220 would be better but then I'd also get a different crank too probably.

 

Theirs some soon to come out.

a shop car we had at Speed used a Callies Magnum 3.75" crankshaft, 383ci LQ9 with twin 70mm turbochargers.

 

Hmmm. 4.03" bore, 3.825" crank, 6.2" or 6.25" rods... Call it a 389 for us Poncho fans.

 

Not wanting to hi-jack...but can a 4" stroke be used with stock rods/pistons in an lq4/9?
I'm looking to do this if feasible, and would be N/A only.

 

No you need different rods and/or pistons.

 

If you look at a 6.100 rod or a 6" rod even, the piston options can open up a little. Alot of people think that custom pistons have to be made for applications like that, but for the most part, as long as you can get a rod that is long enough to clear the counterweights and the pistons are clearanced for the timing wheel, then you can get away with making it all add up to 9.2x.

Keith Black just came out with the 3.905 pistons for that 3.825 crank. Uses a 6.125 rod as well. Im looking at helping a friend build an engine with that one. Call it a "half stroker" lol.

At 366 ci with some nice CH numbers it would be a killer idea really.

 

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