I have a lm7 from a 03 Silverado that I plan on putting in my 240sx and twin turboing it. I was wondering if the lm7 with the 317 heads and a wiseco rkd20111 rotating assembly would be a good combination the rotating assembly specs are

359 ci
3.780 bore
4.000 stroke
6.125 rod length
-7 piston volume
11:1 cr with 58cc combustion chamber
10.5:1 cr with 61cc combustion chamber

I was wondering what kind of cr would it have with the 317s I know they have a larger combustion chamber than the stock lm7 heads. Has anyone ran this combination before or am I just crazy for wanting to twin turbo a 240sx

 

317 heads have a 72 cc chamber That will make you CR really low.

What fuel do you plan on running and how much power do you want. I would pick up a 243 head or 799 head and be right around 10:1 CR for pump and Meth

 

But wont the cr be higher with the wiseco rotating assembly than the stock lm7 rotating assembly

 

Are the specs you listed for the Wiseco rotating assembly??

 

If my calculations are right using the standard head gasket that compresses to .021", and the wiseco piston s have a 7cc dish and the 317 have a 72cc combustion chamber will make the total combustion chamber about 87.2754cc and bring the cr to about 9.4:1

 

Wonder how that 4" stroke would work out with that bore.

 

Yes they are for the wiseco assembly

 

The 4" stroke will make for a really torque-y car. LilJohn and myself have discussed a very similar engine for an Ultra Street/Real Street car.

 

That is what I am wondering I haven't ran across anyone using this kit and I think if my calculations are right then it would give me a decent setup for twin turbos that would be a forged bottom end and still run pump gas and not be doggy out of boost

 

I just thought it might be a decent combo that I haven't seen done in the research that I have being doing the last couple of weeks I have read a lot of builds and haven't seen anyone use this setup

 

Yea thats pretty interesting. Wonder what you would spin something like that to with the larger stroke.

 

Well at 6000 rpm would make piston speed 4000 fpm
And 5700 rpm would be 3800fpm
So with a forged assembly I would say that 6000 rpm is about it

 

I have read that ls engines start to fall off at 6700 rpm so I could see keeping redline between 5700 to 6000rpm to be reasonable. Do yall think this will work in a light*** 240sx

 

Im pretty sure tou can spin it much higher then that, 6800-7000k

 

You dont think the piston speed would be to high

 

I dont think so. Where do you find info on that rotating assembly? Wiseco doesn't make rods or cranks so I wonder what they are using on thr kit

 

Found it. K1 steel rods and k1 crank. Wonder what those rods are good for.

 

I believe the rods and crank are made by k1 http://www.wiseco.com/Catalogs/Rotat...eteCatalog.pdf page 8 and I doubled checked it is a k1 crank and rods

 

What are your goals for the build? Are you racing it quarter mile?

My JY build 2001 dished piston 5.3 with 317 heads and LS9 MLS head gaskets (.051 thickness compressed) put me at 8.6:1. Ran a t4 1.10 S475 turbo with the small 83/74mm wheel. 3500ish stall and 3.10 gears with a power glide.

It was worthless on the street at anything above 12lbs it would spin 29x12" slicks. As soon as it flashed the converter it would make boost. 24-25lbs at the track was enough for 8's on a JY stock shortblock. Through the traps around 5800rpm. I shifted at 6500. SOme of the local LS 240 builds claimed to be lighter than my car as well. Right at 2850 race weight.

IMO, I wouldn't' worry about the lower compression at all.

 

I am gonna be setting it up to do a couple different events in memphis we have drag, road course, and drift events pretty regular every year, but I still want it to be streetable I haven't chose a trans yet was starting with the motor and goinv from there