I'm considering a 'winter' project and am not having much success with the search engine today. Right now I've got a 347 w/ Wiseco pistons, Eagle rods, balanced stock crankshaft, a 228/228 575/575 cam, some old CNC heads out of Florida, LS6 intake and Grot headers which need to be replaced. I bought the shortblock used and the original owner had intended it as a nitrous motor.

I don't want a huge outlay on this, but I am not particularly heart set on keeping anything off my current longblock. The engine will only ever be naturally aspirated and will be used for ~75% autocross, ~15% daily driver, and the rest road racing. I expect to put 2000 miles on it each year, and would be driven to/from events.

What don't I like about my current setup? The forged pistons are noisy, the valvetrain could be quieter, I want more torque in low RPMs coming off slow corners, I want to minimize weight on the front end.

I guess I'm looking for input as to which cylinder case to begin with, then break down what if anything I should consider keeping from my current engine. The components need to be relaible, and light rotating assembly woudln't be bad but not sure if the additional cost is justified. I'm not looking to set any dyno records, but want the engine output to be designed around it's use. I don't need to be tearing up slicks which cost $450 each due to too much power

Due to classing restrictions, I can't increase my stock displacement more than 15% without being bumped into a class I don't want to be in. So that means 396ci or less.

So based upon that alone, is it worthwhile for me to consider a LS2/L92 setup?

 

hell yes, you should for sure do an LS2/L92 set up.

even though you said you wanted more torqe, id get a sleeved LS1 block out to a 4.125 bore and put some LS7 heads on it.. use the truck 4.8 crank and the displacment is only 5.7L , if you spent money on the valve train you could spin massive RPMs with that set up..

 

talk to katech about their sneak attack 5.7l ls7's

 

Doesn't the LS1 need to be sleeved to go beyond 3.905" bore? I don't like the idea of sleeved LS1's. Heard too many horror stories and I just won't consider it.

Katech would be great, but I bet that package is $$$.

 

The L92 heads won't fit on a 3.905 bore..

 

...which is why I mentioned a 383-396 LS1, and use a 4" stroke. Are there any other displacement options between 364 & 396ci for the LS2 block? Is it less expensive (and have similar power capability) to build a reliable LS2 longblock than the 383/396 LS1 longblock?

 

How about using the L92 block with a stock crank? This would give you 376 cubic inches and this combo would of course work fine with the L92 heads that you would like to use.

 

I'm just looking for ideas. Would that be the stock L92 crank you're referring to?

 

You could use either the L92 crank or the LS1/LS6/LS2 crank. They all have the same 3.622" stroke.

 

Any idea what the an OEM assembled L92 shortblock costs? I haven't been able to locate a part number for anything except the bare block. I'm just wondering if it's less expensive (and just as reliable for my application) to buy the GM block and swap in the 3.622 crank than to go overboard with an aftermarket rotating assembly.

 

Starting to build an itemized list for a new 377ci L92. For the 3.622" stroke, what length connecting rod will I need? 6.125"?

 

You could probable stuff a 6.2" rod in there seeing as how it will most likely be a custom piston anyway. It really comes down to what you want though.

Nate

 

What do I need to consider when picking the rod length?

 

I think that the 6.125" rod will be fine. You are using a 3.622" stroke crank so the rod angle is already much less than it would be with a 4" stroke.

 

do you mean re-sleeved? it already has sleeves in it

 

Yeah, re-sleeved

 

Either use a L92 block and stock crank for the build or a LS2 block and a 3.90" stroke crank, that will keep you under 396 cubes. Either way both setups with nice forged pistons will need custom pistons. If you set the piston to wall clearance right and run a 4032 alloy piston everything should be quiet.

I'm personally doing a L92 headed LS2 build up with a light rotating assembly for myself.

Bret

 

JimMueller, i would take LS2/L92 H/C over LS1/LS6 383 becuase for almost same cubic inch i prefer more bore and less stroke over less bore and more stroke. i feel that way you will get better power band for the bigger bore becuase with bigger bore you always can better heads. and always go with more cubes until the bore is equal to the stroke. i feel that way you will get good power band that will acelerate you faster. perosnaly i would take LS7 topend with 427ci short block for either NA or turbocharged or supercharged. i don't like superchargers actualy actualy i like turbochargers.

 

A 3.9" stroke crank would be custom, no? Does it cost more for a custom crank than it would for a standard stroke, everything else being equal?

 

Eagle has a 3.9" stroke crank available. At least they used to.

Mark