Alright guys im currently taking a class for college and one of our assignments is to rebuild heads. So I was thinking of finding a pair of 243's or 799's, I could just use some random ones for the class but since im doing it I might as well do it for my truck right? Iv got an 04 2500HD LQ4, lsxkiler tune, cai/exhaust. Is swapping out heads practical for a mostly stock engine? It will have a cam put in someday but no time or money now for that. Is it worth the time or should I just wait on heads and do cam first? Thanks guys!

 

head swap would be a great idea to bump compression up, but id be worried about making the computer happy with the extra compression. you might need a tune with that which will cost$

 

Re tune won't be a problem!

 

Yes heads are a great idea! Your 317s are good flowing if you mill them for more compression.

 

Does the instructor/yourself know how to properly port or are you allowed to port? I would open the exhaust ports some, remove the rocker lumps, and swirl ramps in the intake ramp. A light diy port job should get you a solid 10-15 hp, plus mill them for another 10 solid 25 hp for the cost of gaskets bolts and time sounds pretty sweet. If you mill the heads you will need shorter pushrods and a checker. Thats a 100 added on the project but you will need them for the cam any ways. 243/799 will give more compression than milled 317s

I would replace the lifters and trays while the heads are off.... it is the perfect time to do so.

 

I'm not sure if we can port or not but I can ask today! And yeah I'll be getting hardened push rods anyways! Will I have to change pushrods length twice if I put my heads on before my cam?

 

depends how aggressive you go...

ALWAYS measure it is cheap insurance

 

Should I just mill port and polish 317's or try and find some 243's? 243's came off ls6 and ls2 right?

 

A lot of work for a minimal gain. My truck put down 404/391 with stock 317s.

Best option for you, imo, is a higher stall torque converter and a tune.
Maybe some LTs and a free flowing exhaust also.

 

If you mill the heads you will definitely need some shorter pushrods and every motor is different slightly so a $20 push rod length check is perfect. I prefer the comp cam one, had a trick push rod checker and the nuts are in the way making it useless.

The 243s will have a smaller cc chamber than milled 317s, b/c I wouldn't mill heads more than .03 IMO deck surface starts to get to thin. But 243s will run you +/- 300 and the 317s are free so I would just use the 317s milled and spend that 300 on good springs, pushrods, lifters gaskets etc.

If you are trying to save some money I would do the headers and cam at the same time so you can pay to have it tuned once.