I have plans for next spring to swap a "budget" LQ4 into my 3rd gen T/A. The plan has been to throw in a custom grind cam from Pat G, Ed Curtis or the like, bolt up an f-body pan and accessories I have laying around, and top it off with an LS6 intake ('03 lq4, cathedral 317s), with hopes of 380rwhp but with more concern for area under the curve torque for street/corner carving use.

To throw a monkey wrench in things, I have an opportunity to pick up a set of newly CNC ported 799 heads locally. This would completely throw off the "budget" aspect, but they are affordable for me. Also included is a new cam w/ 237/242 duration 595 595 lift. Seems like a little more duration than what is recommended on here via search for an LQ4, although most examples were for non-ported heads.

Questions:
1) Will the gains from the compression bump of the 799s be worth doubling the money I have invested in my LQ4 over cam only with 317s and supporting valvetrain? Keep in mind, I have no reason to pull the heads otherwise.
2) Is the 237/242 595/595 cam thrown in with the deal worth having, or am I better off in the 228-232 range for street/autocross use?
3) Just for fun, can anyone throw out some guesstimated dyno #s for a moderate cam/317 set-up versus moderate cam/799 combo?

Thanks for playing along.

 

I would go with the ported heads and cam package. I think with on a 6.0 motor that combo would make 430+ at the wheels comfortably.

 

Thanks for the reply. Anyone else have any thoughts?

 

Yea it's worth it to go with the good heads because that is where the power is made. Plus you could recoup some money from the 317s (100-150). The increased compression will also work better with the cam you are looking at.

 

What about some 5.3L heads? They'll give you a nice bump in compression to help with overall power, and should easily get you over 400whp with about $300 worth of work and you can pick up a set for less than $150.