Hoping some of you can help me out with a few questions regarding my LQ4 build. I just read through 10 pages of topics with "LQ4" in the title and I think I have a pretty good understanding of what I'm dealing with, but I had a few questions specific to this build that I wanted to get some advice on.

I'm getting a low mileage LQ4 short block with a TSP Torquer V.2 cam, LS1 heads with Patriot dual gold springs, and a Professional Products Typhoon 96mm polished intake and throttle body (and a few other small things...pushrods, ported oil pump, etc) in a trade. This motor is going in my '01 WS6 that's in my sig. I plan on keeping the short block, cam setup, and valve springs for sure. Everything else is up in the air. Would like to maximize the power I can make with the LQ4 shortblock and existing cam, along with the other supporting mods I already have (see sig). Would like to see 425+, but I'm not too concerned with dyno numbers alone.

Heads are the first order of business. I've been looking at PRC 5.3 heads as well as PRC Stage 1 and 2.5 LS6 and Patriot LS6 heads. I know the LQ4 has lower compression due to the dished pistons, so I'd like to bump that up to as high a level as I can on pump gas and not have to flycut. I'd love to throw some AFR or TFS heads on, but it's just not in the budget, unless I get a killer deal on some used ones. Would the PRC Stage 2.5 5.3s work OK with the TV2? I had read about how the 243 heads may work better with the LQ4 due to their design and the increased displacement of the 6.0l, but I'm unsure on that. I know the desired compression will be easier to achieve with the 5.3s, but if I need to get some ported 243s and have them milled, I can. So some suggestions on a head combo would be great.

I read a lot of conflicting info on the PP Typhoon 96mm intake and TB. Most of it indicates that the mani is prone to heat soak and really not worth the money to swap from an LS6. I have both options available (I still have my LS6 intake and Shaner S3 from my old motor), so I just want to use what will work best for me. I read where the Typhoon gives up some low and midrange power to the LS6 but gains a little on the top end...not sure how much this would be affected with the additional cubes of the LQ4. There's also the weight issue. If the LS6/Shaner is going to be just as good, then I'll sell the Typhoon and 96mmTB. If I'm going to see a justified benefit from keeping the 96mm mani/tb, I'll keep it.

Any other suggestions or comments you guys might have would be welcomed. I'm set with everything I need for this swap...the motor is already coming out of an F-body, so most of the necessary items have been done for me. I know I need my accessories, LS1 oil pan, etc, and I think I have all that covered already.

Thanks guys.

 

Where are all you LQ4 guys at?

 

If you had the BBK and not the Typhoon you'd be good to go, but I haven't heard too many good things about the Typhoon intakes. Nor have I seen many if any results showing any gains over the LS6. If you have the LS6 I'd probably just stay with that and sell the Typhoon and use that money elsewhere...

Milling the heads is the way you wanna go to up your compression. Just remember you don't need a HUGE cam. A smaller cam will give you a ton of torque and be VERY street friendly on that 6.0...

What are the specs on that Tourquer 2?

 

TV.2 specs are:

232/234, .595/.598 on a 112

 

From what I have read the 317 heads are the same as the 243's but with bigger chambers and they are cheaper then the 243's if you are gonna have them milled anyway. I think a lot of guys are useing the l92 heads with the ls3 intake and getting some incredable number. Look up the episode of horsepower tv they did the same thing and I want to say they got close to 600hp at the fly. Good luck.

 

I was considering the L92 setup, but iirc the chambers are like 70cc, and I wasn't sure how much I could safely mill.

 

Going to bump this. Still debating on heads...ported 5.3s or ported LS6. Either set will be milled to bump compression. I'm also debating on swapping the cam for another if I a larger one will make a huge difference.

Any suggestions on a combo?

 

I have some lightly ported 5.3 heads for sale $150 shipped if your interested. Pm me if you are.

 

Thanks man, I'm looking for a little stouter head.

 

why not just mill a set of l92s?

 

How much can I mill them? I was under the impression that they were 70cc heads, but I could be wrong. If they are 70cc, those heads combined with the dished pistons of the LQ4 would give me 9.67:1 compression. Even if I mill them down to 67cc, the comp will still only be 9.98:1. I was hoping to get to 10.5:1 or better. Am I missing something?

 

I would call WCCH or a Mast and ask them about their L92's. I know WCCH's heads kick *** and they are reasonably priced, and I bet they can configure them to meet your needs.

 

They can be milled more but some of the valves they offer are pretty large 2.08" intake. As always, beware of P to V clearance!

 

i never go more than .030 on any oe head total. imo would go with prc ls2 243 heads or the 5.3s version.
the 5.3s milled will offfer the highest scr.
if your gonna use a long duration cam, cutting vr's in the piston is a wise idea.
final scr will depend on gaskets used, which heads, how much milled, and vr volume. but with the 243 or 5.3 it will be closer or beyond 10.5:1

 

The LQ4 pistons have 8cc valve reliefs...you think I will need to flycut? I was hoping not. Looking at around 62cc for the combustion chamber on the heads I buy, regardless of 5.3 or 243s. According to the figures I was looking at with a stock head gasket, compression should be 10.55:1 with a 62cc head.

I'm also considering swapping the cam out for something else, maybe a little larger like the MS3 or Tsunami. Thoughts? Just trying to get a good combo for the slightly extra cubes I'll have. It's hard to plan this out since most of the good head/cam info out there is for a stock 346 LS1...I don't even know how much of a difference the extra 18cid will make, or if its something I should plan around.

 

yes, even with the 8cc dish. i have always cut in relieves. esp when using milled heads and thinner gaskets. ive ran trex on lq4 before. with milled heads and thinner gaskets. even with the dish it was too close for comfort for me.
the ms cams are very similar to trex. so i would assume preparation is the same. i degree any cam, and verify final ptv clearance. you may not have to cut. but doenst hurt to verify. i keep at least .100 clearance. however differnet cam mfg. use different lobes. so similar duration cams may not have similar valve events. even though the durations may be close

 

Cool, I may just stick with the TV.2 then. The motor is set up with stock 241s now and didn't have any PTV issues, and Matt from TSP said they could safely mill their 5.3 heads down to 60cc and clear the TV2. That may be the best option for me.