dtom001

The 2001 aluminum-head LQ4/4l80 combo that I got this weekend turned out to be a 2000 iron-head LQ4/4l80, so I'm looking at my options to swap out those heads and intake for something lighter and better! Does anyone have any good suggestions? This will be going into a 1964 Bel Air 4door, and I'd like to not need big-block springs in the front end after the swap. I live in the Colorado mountains and occasionally need to turn when I drive.

I think that my most-stock path is to stick with the 2001+ aluminum LQ4 heads (Gen III). I think I could go with the LQ9 heads but wouldn't I need to change the pistons to LQ9s for it all to work correctly?

I assume that I could bolt on a lot of the 4.0-bore Gen IV heads (LS2, L76, L98, LY6), but it seems like they come with additional tech that my Gen III computer couldn't use, variable cam timing and phasing and cylinder deactivation and the like. What about the L92 heads? They're designed on a 4.080 bore, so would the valves end up hitting the block?

Thanks in advance, Tom

scj

iTrader: (89)

lq9 and lq4 heads are exactly the same, 317's. You can bolt on these with no modification.

sierrac3_s2000

iTrader: (6)

If you are going to purchase heads go with the L92 castings and a LS3 intake. That setup with a good cam can make some really big HP. All of those parts will work with your GEN 3 ECU but you will need a cable operated 90mm throttle body.

71ANTICARB

iTrader: (23)

Is your goal more weight savings or power gains. If it is power the L92/LS3 setup is really good for some big power on a reasonable budget (still about $1100-$1200), if it is just weight savings you can get the LQ4/LQ9 317 heads (about $150), or you could go with something like the LS6 243 heads (about $300-$400) which would get the power and weight without having to change intake and throttle bodies. Another thing to consider about the L92/LS3 is the rectangle port heads love a huge cam and it won't make much more power without one. IMO.

dtom001

Thanks for the great info! Right now I'm more worried about weight and getting the engine installed. I'm also not that concerned with power in the long term, as this chassis, though it is fairly light, isn't stiff enough to handle tons of power and won't be raced. It sounds like my best and most straightforward swap will be to find some aluminum 317 LQ4/LQ9 heads, so I'll start looking.

Thanks, Tom

claytonisbob

iTrader: (1)

I thought it was the other way around. The L92 heads can make some pretty big numbers with a relatively small cam compared to what many people with cathedral port run a bit bigger cams. I guess that's all subjective though to what people think is big vs street-able ect.

My opinion based on budget:
Very low budget: some 317 casting heads or if you can find them some LS6/LS2 heads (243). The 317's are actually really good heads and are designed about the same as the 243 heads, but with a larger combustion chamber. Switch to the 243's to pick up a really decent compression upgrade. You can also mill (or get thinner head gaskets) the 317's some to do the same, but you'll decrease the ptv clearance for some of those bigger cams. So unless you plan on running something pretty mild, that might not be the way to go.

Medium budget: L92 heads, LS3 intake, LS3 aftermarket cam. Actually, this can get more expensive especially if you do get a cam for this swap (ideally). There are a few extras things you need for this (new intake rocker arms being one). One major downsides to these heads, they're 70cc, so essentially you won't be raising compression ratio at all. You can mill them, but again, that will decrease ptv clearance (without flycutting). And the fact that if your running drive by cable, you'd have to get a 90mm cable throttle body (starting at $370+). You can get pretty good results with a small cam, but to get the full effect of the head swap, look into some of the LS3 cams in the Gen 4 Engine forum here.

Higher budget: aftermarket heads. This really can be the same or cheaper than the option above. Especially if you get some C&C'd GM castings. It really will boil down to supporting mods (intake and cam).

I will say that if you are just looking for a decent improvement in what you got on the cheapish: get some 317 heads, have them milled .030-.040, and get a hot cam regrind with some of the yellow corvette springs. Keep the truck intake if you can fit it in your car (it's actually not bad up to the higher, 5500+ RPM range). You'd probably need some bigger injectors if your looking to make any extra power. I did this combo and got some LS2 injectors on the cheap. It also turned out I didn't need custom length push rods because it seemed the milling of the heads and the smaller base circle of the reground cam worked in my favor (not always going to be true).

65SSZO6

iTrader: (4)

I have a 04 LQ4 in my 65 Chevelle that has aluminum 317 heads,ZO6 cam matching yellow springs,LS6 intake,Janzer P/P throttle body,fuel rail and 42lbs injectors for sale here in Colorado.Combo has less than 2k miles. Can see build here on LS1tech.com. PM me if interested.

Pocket

iTrader: (22)

Dont forget, the iron headed 6.0's were the ones with a cast in crank spacer so you're limited to the 4L80E or older SBC trans choices. To use a modern 4L60E or T56 you'd have to change cranks

dat260

Hi,
I'am in the process of buying an lq4 from a 99gmc pickup truck complete with harness and computer. I want to mated to a t56 but you say the crankshaft must be changed.
Now when you say "older sbc trans" do you mean an older manual transmission or you are still reffering to an automatic?
cheers,

Thirian24

Like everyone else has said, Im going to run the L92 heads with the L76 intake on my LQ9.

xlcooplx

iTrader: (26)

Exactly what I was going to reiterate.

Jimbo1367

Good info pocket

Jimbo1367

I believe 06-09 Monte/Impala SS 5.3L came with the LS6 (243) heads. Should find them cheap

dtom001

Thanks for all who replied! I'm keeping the 4L80e that came with the engine even though it is an extra 80 lbs fatter than a 4L60. It's a great transmission, I've heard that it has fewer tunnel fitment issues than the 60 and besides I already own it.

Jimbo that's a great piece of info on the modern Impala heads, I'll keep an eye out. It'd be great to get modern Impala parts into this ancient Impala! Maybe I should grab the seats from a '96 Impala to get parts from every generation into this one. I was on the lookout for a 70s Impala 12-bolt rear end but it looks like I'll need one from a 64-67 or 68-72 Chevelle to match the flange-to-flange width with what i have currently.

dtom001

Do a search for "LQ4" and several posts on this issue will pop right up. In short if' you're committed to a T56 you should reconsider your purchase of a '99 LQ4 for this exact reason and purchase one that is DEFINITELY '00 or newer. The newer engines are distinctive because they have aluminum heads, while the older LQ4 heads are iron. A magnet will tell you the difference, or the suspicious presence of rust.

Irish350

iTrader: (14)

lol

my vote is for ls3/l92s and a matching intake.