LQ4 with 706 heads = more power AND mpg????
 

i have a stock 2005 lq4 in my crew cab 1500 only thing done to it is longtubes and ORY and a RWTD tune...

what would the compression be if i used stock gaskets and milled a set of 706 heads .025? and do you think the power would be worth changing to the heads? and also do you think the MPG's would go up or down drivin the same way i drive it now (17 highway and 14 town)..

i will eventually put some type of cam (220 or 224) in it

I dont think the stock 706 heads flow that well for a 6.0...if you went aftermarket like the PRC 2.5 that is a different story.

they flow good enough for a daily driver THIS IS A CREW CAB ON 24's not a racetruck...
and also for $250 i can get them milled and the valves from a 317 head installed into them for a little more flow...

listen to the advice requested.

Perhaps a set of 243/799 heads, which flow better, as well as your stock 317's and will increase compression with 64cc combustion chambers.

With increased compression you will have better low end.

And with 243s you wont need to Mill them like the 317s or buy valves, Same valves as 317.. There was a few sets floating around on tech anywhere from $300-500 shipped.

When I went to the swap meet in Englishtown this past summer I saw sets of 243's everywhere, they were aplenty

I dont think you'll see any gain in MPG. I increased CR 1/2 pt with no change. Also, the cam will cost you 1-2 mpg.

dont due it man ! yes the compression will go up with 706 but the top end flow will drop like a sack of potatos! i went that route and know i have to speend cash again just to get some better flowing heads ! if you can get the bigger valves then thats cool! but you can probable get some 799s or 243s for an extra 100 bucks and they already have bigger valves and the flow better as it is becouse its a better cast then the 706s! dont due it!

243 heads
Intake Valve Diameter: 2.00 inches
Exhaust Valve Diameter: 1.55 inches
Stock Head Flow Numbers
Chamber 64.45 cc-------0.100---0.200--0.300--0.400---0.500---0.550---0.600
Intake 210 cc------------62------126----184----224-----251----256----257
Exhaust 75 cc------------57------108----143----163-----176----180----183

706 heads
Intake Valve Diameter: 1.89 inches
Exhaust Valve Diameter: 1.55 inches
Stock Head Flow Numbers
Chamber 61.15 cc----0.100--0.200--0.300-- 0.400--0.500---0.550---0.600
Intake 200 cc----------63 ---128----179-----210----218----221-----226
Exhaust 70 cc----------54 -- 93 ----121----145-----163----168----174

317 heads
Intake Valve Diameter: 2.00 inches
Exhaust Valve Diameter: 1.55 inches
Stock Head Flow Numbers
Chamber 71.06cc----0.100---0.200--0.300--0.400--0.500--0.550--0.600
Intake 210cc-----------66-----142-----196---228----236---238-----240
Exhaust 75cc----------59-----104-----137---155----167---173-----177


with that being said... I PERSONALLY think the ONLY difference between the FLOW of a 706 and a 317 is the valve size ONLY....CORRECT???

I was under the impression that the 317 and 706 had different ports also, while a 317 and 243 are virtually the same besides the combustion chambers