: 2000+ LD8 vs L37 - What's the diff?



Rocket88
03-27-10, 12:40 AM
Just trying to sort out exactly what the difference is between the two on the newer N*'s.
I've read around here that there were some larger difference in 90's vintage N*'s, but haven't found a good listing of differences between the newer ones. I have heard that there is a different part number for the LD8 heads, but is that just related to cams? My understanding was that it was just a cams and tuning difference, but would like to know if I am right on this.
Inquiring minds want to know! :)
Thanks

Mark C
03-27-10, 09:08 AM
As far as the mechanical parts of the engine its just the intake cams that are different. Tuning differences are done by the PCM.

Rocket88
03-27-10, 11:55 AM
So the differnt part numbers for the complete heads would be just due to the different cams being in there, correct.
So, if one overlooks the minor details of PCM tuning and final drives, then a LD8 could be turned into a L37 "simply" by swapping by swapping the cams?

Ranger
03-27-10, 03:34 PM
Yeah, but it won't run well due to the wrong final drive and PCM.

Rocket88
03-28-10, 12:35 AM
Yeah, but it won't run well due to the wrong final drive and PCM.

Which is why I said if one "overlooks" those things... :)

Actually, I have a Bonneville GXP, so I have the gearing part down already. Just need to do the PCM tune.

AJxtcman
03-28-10, 12:25 PM
I guess if you wanted to give up all that torque you could swap cams

http://i224.photobucket.com/albums/dd25/AJxtcman/dyno/TorqueCurve-00.jpg

Rocket88
03-28-10, 01:05 PM
Not THAT much torque.

I figure I am a couple of hundred pounds lighter than a STS, with the same gearing, so it shouldn't be too bad. The STS seems to pull pretty well.

With the short gears in the GXP, you can certainly feel the power dropping off in the upper range of the tach. Ihe think the gearing on the GXP is a little short for the LD8. Maybe something in the 3.4 range would have worked better?

That engine is so sweet, that it should pull smoothly and strongly to the redline.