01WS6/tamu

iTrader: (36)

What is the max that you can mill 317s's on an lq4 and still be in the safe zone. I'm putting in an lq9 cam and leaving it alone for now other than that. It's a project motor im working on. Might do a set of headers in the near future for now I just want to get it in and running.

dlt76028

iTrader: (13)

i went 30 thousands and use 7.4 pushrods

1FastBrick

iTrader: (17)

I believe you can go around .040 thousands. Factory cc is 71.15 so .030 would be around 68 cc combustion chamber...

curoius why bother with the LQ9 cam and milling the heads???

Depending on the year, The LQ4 should have the same cam as The LQ9.

Part# 12560967 '99-'00 - 191/190 .457/.466 114lsa also used in the 4.8/5.3 from 00-04
Part# 12561721 '01-'06 - 196/207 .467/.479 116lsa

regency

iTrader: (15)

LQ9 and LQ4 cams are the same. And ANY motor will benifit from head work regardless of what cam. An increase of 1 point in compression is 3-4% more power

01WS6/tamu

iTrader: (36)

I just had the cam laying around out of a customers truck that I slid a comp cam into. SOO that submarines my cam swap being as it's the same cam I just figured it was a bit hotter coming from the lq9 denali. My shortblock is an 02 model. Guess I'll go with a cam from comp mill the 317's 30 put it together and see how she runs. Just wanting a nice daily driver out of it no racing hotrodding etc. What kind of compression are we looking at with the heads milled thirty to forty and stock lq4 bottom end. Or if I bit and went with a set of ported 5.3 heads with bigger valves what kind of compression are we looking at and or performance difference.

Mangled03gmc

iTrader: (95)

I went 20k off mine, used the 7.4(hardened) rods. The Hp diff in the two motors, comes part from the lq9 having flat top pistons(more comp) then the lq4 being a dished piston engine.. Cams are the same.. You should be fine on a 30k mill

1FastBrick

iTrader: (17)

I think you will be right around 10:1 with milling the 317 heads... should be good for a dd combo depending on the cam you pick... I wouldn't do the 5.3 heads because they have a smaller Valve in them. You will have to get new ones so It can breath...
Head info here... https://www.performancetrucks.net/fo...6&postcount=17

5.3L heads have a 1.89 intake 1.55 exahust
6.0L heads have a 2.00 intake 1.55 exahust


stock for stock the 317 flow better any way... just strip the ones you have and do a little bowl clean up and better springs. Slap a new cam in there and you should be Happy with it for Little expense... I know my pictures suck but basically just smothing the area around the guide and clean the bowl area so it smothens out from the seat into the runner will make a world of difference.


Since the heads are off for milling and you will be putting in a new cam Get some new lifters and trays while your at it. The trays are cheap, I bought mine from scrogin dickey there like $3-$4 each. cheap insurance..

1FastBrick

iTrader: (17)

oh get hardend push rods too...

trembles

denali's came with lq4

01WS6/tamu

iTrader: (36)

Thanks, appreciate it.