what sucks is i really dont have the time to have the truck down being thats its my dd

 

If it was on the 07< models I would tell you to go for it but I just have not seen it on the NBS for some reason. I've actually seen some loss of performance or minimal gains. It's not that your concept is wrong it just that it is hard to get timing when you raise the compression on these new trucks. Has anyone tried it here? Maybe some tuners can chime in.

 

im told the 2.5 5.3 heads flow like 300 or so . is that good?well im undecided rite but my tuner/mechanic is expecting 25-30 hp increase on the head swap. is he crazy? does it sound about rite

 

on average you will see a 4% gain in HP and TQ for each point of compression. But it will be everywhere in the power band not just at peak. Should be a nice gain with the ported heads combined with the added compression. Rather than mill the **** out of the heads I would do as mutch as I could with a thinner gasket.

 

thanks guys ,anyone else tried the texas speed 2.5 5.3 heads?xpieriences

 

The NBS setups do run alot less timing, same with the new 6.0l vortec max etc

The current tune runs runs 22 deg's. 23-24 gets occasional spots of knock retard...


Swapping to a set of CNC ported 5.3L heads over 243's has shown solid 30-40rwhp gains on all the 5.7l ls6 setups with 243's I've done. Also the power gain has been across the board. The cnc 5.3l heads outflow the stock 243's by a ton and the slight compression increase (running them non milled at 61 cc) will not give any issues with timing/detonation. Actually the head will likely have less detonation and possibly take more timing due to the increased efficiency.

 

Does anyone know what size valve the 243's on the NBS trucks have (4.8 and 5.3). I'd like to get a set of those 243s for cheap and put them on my 6.0