Hi guys,
So I'm wanting to put together a modified LQ4 to swap in place of my 350. I'm making sure to do my research and am going to take my time doing things so they get done right the first time. As I'm going over the multitude of different threads on the subject, a few questions comes to mind about the build I'm wanting to accomplish. Sorry for the read, just want to get a good idea of what I should be using.

Is it possible to make a setup that hits in the 400-450 crank power range that is also fairly driveable? I took a trip to Kentucky with my fiance about a month and a half ago to see the Corvette Museum (spoiler: kinda disappointing) in my G6, and while it wasn't awful by any means, it really made me miss the power I had in my C4 before I sold it. I know I likely won't get to that same level of driveability, the C4 was a 3200lb fiberglass arrow and the LQ4 will go in a 6000lb truck with the aerodynamics of a wide cardboard box with an open front and a closed back end, but I'd like to hit it better than the G6 did.

My primary goal is to have it act as a reasonably fun secondary daily that will be situated mainly towards daily driving or working use, with a secondary goal to make it usable for some long trips. I'm not meaning to make it into a cross country type of vehicle (G6 got 30mpg on the trip), but I'd like to go out of state with it occasionally if it is possible to do so considering the primary goal.

My first thought to make it possible was to use a supercharger, basic bolt-on power that doesn't require rerouting a bunch of components and should be relatively easy to install and tune for. But, I'm not sure how the block or internals would hold up to the supercharger over time, or how easy it would be to get a belt for the supercharger a decade or so down the road (course by that time maybe we'll be served by robots and gas will be a rarity). Then, adding a supercharger will mean needing to upgrade the cooling ability past what the basic LQ4 and 4L80E would require, yea? But, if I go with a supercharger, I figure I can save a bit of money and keep the 317 heads on the LQ4 since the 317's should have more than enough room to do well with the extra boost, and then I should just need to focus on the few supporting things it will need as well as preventative maintenance items while it's out of the truck (oil pump, main seals, timing chain, knock sensors, maybe lifters and springs, injectors). Additionally, I should, I think, be able to keep a good chunk of low-end torque which will do good for city driving.

On the other hand, could a naturally aspirated solution be available? It would keep the stress from boost off the block and internals, and maybe even keep the budget down some (last I checked, superchargers were pretty darn pricey). I figure I could make use of the 706 heads off a 5.3, they're a dime a dozen and most of the 5.3 guys tend to ditch them pretty quickly so getting some at a good deal shouldn't be an issue. From what I'm reading, the smaller chamber should do well to increase efficiency if paired with the right cam and intake, which should I think help with power and torque, yea? I can always keep and store the 317s if I decide I want to go bigger later. For a cam, I figure go with something in the 220-230 duration, keep torque and power numbers in the mid-low range and not so far outside of stock duration that the idle gets too rough/choppy. 230 might be too big a duration for what I'm looking for, but I really still don't understand cam measurements so I've no real clue. For intake, I would think maybe a TBSS intake w/ matching TB? Seems to be a common choice for folks not doing huge power adders, though admittedly I don't know the benefits between that and the regular LQ4 intake, though I think the TB on the TBSS intake is a bit bigger than the TB on the LQ4 stock intake, yea? Or is there a better intake I should be using for this?

I guess when I get everything taken apart for it, even though the power increase isn't huge, I should probably replace the connecting rods and the rod bolts with something sturdier since they look to be a weak point on the LQ motors. I've seen a couple of people mention Callies rods, are they still a good quality part or is there something a little better for the application I'm going for? Any recommendations for the rod bolts?

~Ken

 

LSA supercharger or small turbo

 

Edlebrock TVS2300 kit, comes with everything except fluids to install it. as long as you keep the boost to 7-8 pounds you won't even know its there till you hit the loud pedal.

 

400-450 crank HP on a 6.0 is mild bolt-on territory.
TBSS intake manifold and a decently free flowing filter or tube/cone filter, long tubes and good Y-pipe or duals, decent tune, and a fresh set of plugs will get you 400 at the crank on a 6.0.

 

I got your N/A recipe. Mines an lq4 with ls2 rods, flat top pistons, 220/224 .585 lift on 112 LSA, spring kit, ported 317 heads, moly pushrods, ported throttle body, gtp injectors, cold air, and long tubes. It's in a squarebody K5 weighs roughly 5600lbs. Nv4500 5 speed and 4wd. I get about 15 mpg around town and 18 on the interstate. It cruises pretty good and will bake 33" tires through the first 3 gears. Never been dynoed but I'm guess somewhere between 400-450.

 

400crank Hp in a 6000lb truck is still gonna be a Dog compred to a slow C4 lol
The torque from that LSA blower or the TVS will be SO MUCH better and wont shift the power higher in the RPM range....

A N/A setup will work just fine but you will want to regear the truck to really wake it up witch brings the cost up to the price of positive displacement blower/supercharger

Just my opinion

 

What compression ratio do you get with the ported 317s and the flat top pistons? Are you using the stock truck intake, and how do you find it’s city/town driving is? I figure it’s a definite night and day from the stock motor, but anything you wish you did differently with your NA setup?

 

Compression will be 10:1 with flat tops and 317s
but if your going to go through the trouble of flattops it would be cheaper to just start with a lq9 by the time you buy pistons (and rods if your lq4 is gen 3) headgaskets/bolts you would be better if starting with a lq9

 

Slow C4

What gearing are you thinking would be a good wake up for it? It’s got a 3.73 rear end and the 4L80E has some pretty decent ratios for the first 2 or 3 gears if I recall. The only thing I think would really make much of a difference would be going to a 4.10, but I figured the 3.73 would do just fine for city/highway driving

As long as it outdoes the G6 I think I’ll be happy, which shouldn’t be too hard I think

 

4.10s would be a waste
i would do 4.56 for up to 33s
4.88 for 35 or 36s

The 4l60 has a low 1st gear but not the 4l80
the 4l80 is definitely the transmission to have in this application though

 

Probably be a Gen 3, I wanted to go LQ4 because my understanding was that most 2500’s with an LQ4 in them will have a 4L80E trans and will have most of the accompanying equipment I’ll need to use that trans in my swap. I’ve heard that some of the LQ9’s can be matched to a 4L80E from factory, but that quite a few had the 4L60E with them. With that in mind, even though the LQ9 came with flat tops stock, it seems more practical to me to go for the LQ4 since it should be set up to work with the trans I want. Even though flat tops will be extra, it potentially saves me a bit of headache later.

Also, at this point since I asked the hearing question, I should probably mention that the truck this is going into is a 1992 K1500 with a factory 3.73 rear end.

 

Exactly my thoughts, though I don’t remember the 1st gear of the 4L80 being too different from the 1st gear in the 4L60. I’ll have to lookup the ratio and see

As of right now it’s running 33’s (technically 32.8’s)

Edt: wrong use of to

 

I did a full tank of around town cruising the calculated, and a couple hundred miles on the interstate and the filled up and calculated the mileage. Mines got 3.73 gears. I'm sure some will consider in a dog compared to camaros and vettes. It definitely moves good. Taken down a ram rebel, hemi 1500s and gotten close on a couple Cummins.

 

If I was gonna go 4L80E i would do 4.10 gears for a little grunt and still have a bit of economy. Since I'm a 5 speed i stayed 3.73 my first three gears a pretty low already. And the cost of a gear change isn't close to the cost of a supercharger.

 

Gear change alone isn’t, but cam springs gaskets pushrods etc adds up when you do it right and you will push the power higher in the rpm range.
With the blower it will not effect the rpm range of the engine to make more power, and the torque is insane for those things!

And yes if you need the entire driveline then a lq4 would be the way to go! A set of 243 heads would bump the compression to around 10.4:1 without toutching the pistons witch you can pick up for around $300 to $350 if you plan to stay NA

 

If I stay NA, is it better to use 243 heads with their 66cc chamber, or 706 heads with the 61.5cc? How big would the compression difference likely be?

When going to a supercharger on a used likely high mileage motor, wouldn’t it be a good idea to do springs, pushrods, gaskets etc anyways?

Is the difference of long term reliability and wear and tear considerably different between the NA and FI setup?

 

Your 220/224 cam, is that a custom cam or pulled out of another LS series motor? Any recommendation on who to go to for a can like that?

Also, are you using the stock LQ4 intake on it?

 

With the TBSS intake, if you add in a mild cam like what jgaines posted, would that do well with the 317s since you’re already increasing airflow with the TBSS, or would that hurt airflow and overall decrease performance? If it’s an increase, I figure maybe +25 crank hp, yea? Or, at that point, is adding that type of cam gonna be better with the smaller 706 or 243 heads?

 

One thing you might want to do, is google/read the "Iron Maiden 6.0 build" by Hot Rod magazine. They test all these heads, intakes, etc, across 5 or 6 installments.

450 HP at the crank is certainly doable in an N/A motor that is plenty streetable.

I have an LQ4 in my truck. It is not a daily driver, but I do drive it a good bit, including stop and go on my way to work, and occasional highway miles. My setup:

~2005 LQ4
CNC ported 317 heads, but stock chamber size, not milled.
223/231 cam with 0.637/0/617 lift, 114 LSA, aftermarket dual springs and retainers
TBSS Intake Manifold
92mm WARR cable throttle body
FAST/Corvette LS2 33# Injectors
1-7/8" Doug Thorley headers, 2.5" piping with h pipe, largest Borla straight-thru mufflers I could find
4" Intake piping, no MAF, large K&N filter in a cold air box
Holley Terminator X Max computer
4L65e
3200 Stall Yank Pro Truck converter
4.56 gears
33x12.5s
electric fans, I removed the stock mechanical fan

I would estimate this combo is in the range of 450-475 crank horsepower, based on other dynos that I have seen. Have never tested it myself.

Mine has no trouble in 4th gear, locked converter at 1600 rpm, not surging or anything. 4.56 gears is good for this application, which is more of a hot rod truck. If it was a newer daily driver, I would think 4.11s might be slightly better, or going to a 6L80e. I am in the range of 2700 rpm @ 80 mph

Admittedly, mine is a bit of an odd combo. I bought a long block from a wrecker, from an H2 that someone had been running a blower on. So that's why it has CNC'd heads but stock compression. Then other parts like the cam, intake, injectors, I had left over from a TBSS motor. The cam I figure is a decent match anyway, it's a PCM of NC Attitude V2, designed for LS2s in a heavier trailblazer. Does great, will spin both 33s well into 2nd gear. I also had a 5.3 complete (with a dropped valve) and full stand alone red/blue painless harness. So I started with a bunch of parts already, and bought the missing bits to get it completed. Realistically, if I was starting from scratch, I'd have started with an LY6.

Have been running this for 3 years. Only changes that I would make, looking back, are:

1) I would have milled the heads for more compression (don't get me wrong, it runs great and doesn't feel soft down low, I just wish I Would have, to get every last drop out)
2) The Holley Terminator X Max is soooo much better for me than the 0411 ECU + HP Tuners. Admittedly, it wasn't available when I built it, I switched this year right when they came out and have been very happy since..

 

Lots of people like Brian Tooley Racing truck cams for items in this range. Cam Motion, TSP, etc, all have good ones.


Also, I originally ran my stock LQ4 intake an 78mm cable throttle with stock truck MAF. When I changed to the Holley ECU, I also switched to my TBSS intake, 92mm throttle body and got rid of the MAF (Holley is SD)... Truck feels way more powerful, (although my tune overall is much improved), the throttle response is much snappier.