Z28Dave

iTrader: (10)

Not sure if this is the right section but i have decided to its time for a motor swap. the car in question is a 99 Z28 6M. Now this is were is will get tricky in a sense. what all do i need to swap over my LS1 to a LQ9 or 4?

Mods so far are:
TSP STG 2.5 5.3L Heads
EnglandGreen Mayhem II Cam
36# injectors
Ported Fast 90/92
LS7 Lifters
LS2 trays
7.400 Chromoly PS
LT's
and a few bits and pieces here and there.


So i already have a general idea on what can be swapped IE accessories, intake, cam etc etc etc

so my question is will i need a new PCM with the swap?
will the car need to be retuned?
will my 5.3L heads fit on the LQX without piston slap?
will my flywheel bolt on the block?
what reluctor wheel do the LQx have 24x or 58x reluctor wheel?
will any problems arise if my car is DBC and not DBW?

Cam specs are 23x/24x 62x/63x EG doesn't give out exact specs only rough specs of the grind

406chvycamaro

iTrader: (7)

Sorry didn't mean to post. Good luck with swap.

Z28Dave

iTrader: (10)

unfortunately no, although i do need to replace a synchro in it for 4th gear

6.0Nova?

1) Your PCM will work fine.
2) retune is a very good idea, yes.
3) they will fit. piston slap has nothing to do with the heads...it is the pistons slapping sideways in the cylinder
4) your flywheel should plop right in, assuming you're using a later model engine. the very first truck engines had a longer crank.
5) all LQ motors are 24x,
6) huh? why not keep it DBC and keep your old PCM. anything else would just make things complicated.


edit: piston to valve clearance might be an issue with that much lift, but you can always flycut the pistons while the heads are off.

Z28Dave

iTrader: (10)

Ah many thanks, i only asked about the DBW because should i had to swap pcms i wasn't sure if i needed change up some pins or something. also i learned what piston slap really is.

HCI2000SS

iTrader: (2)

I have PRC 5.3 heads and went with a TMS 370ci LQ9 when I blew my LS1. My cam specs were pretty agressive, so I needed valve reliefs with the flat top pistons. I also used the regular GM head gaskets which puts me at 11.5:1 compression. What are you 5.3 heads milled to?

Z28Dave

iTrader: (10)

going to be honest and i cant recall, i bought them from a member here so i'd have to ask him again on the specs. was it hard to fly cut the pistons? or did you have a shop handle that portion? Only asking because i plan on doing everything myself. I have a set of 799s that has a little bit of work done to them just laying around and was reconsidering swapping the heads when i get the motor.

HCI2000SS

iTrader: (2)

Gotcha! No I bought the whole forged LQ9 shortblock from Thompson Motorsports and it already had the reliefs built in. Had a local shop do the install. My 5.3 heads were on a 61cc and with a big cam I definitely need those reliefs lol