L33 5.3 LS for my van.

[racrx7]

So I'm enjoying my 4x4 Astro, except it's lack of torque and power. It just doesn't have the power to pass or to climb bridges. So time for an upgrade. An all aluminum 5.3 L33 LS engine. First to freshen it up and add a nice cam and a lower profile LS6 manifold. Mechanically, I don't foresee any real problems. Nothing some cutting, fabricating and welding won't take care of. The real issue will be the electronics to make it all work like factory. I'll figure it out lol. Anyhow, here's what I have.

[Captn. Crunch]

Cool. The body lift will come in handy with those coils on the valve covers. Most issues I hear of is the ac compressor location down low on the pass. side. There's a pricey bracket to put it back where it belongs

[racrx7]

There's a pricey bracket to put it back where it belongs

I remember seeing something about that. I'll have to try and find that.

[RINNY]

So you will need a different transfer case and possibly transmission? I am going to try to build my 4.3 to get 60 to 100 horse more out of it. I know what you mean by power and torque. I have to do something also.

[racrx7]

The 4.3 and 5.3, most of the LS truck V8s use the 4l60E transmission. There is a slight bolt pattern difference in the bell housings between the two engines. My understanding is you have to leave one bolt out of our existing transmission when connecting to an LS engine. I may just source the correct 4L60E or even better, a 4L65E. (A little heavier duty). As for the transfer case, I am already running 246 internals in the 236 case. Should be ok. I do however, think the front and rear differentials will we too weak to handle an LS engine. Will be looking into upgrading those parts to 1500 Silverado units.

[Captn. Crunch]

I don't think you will need to upgrade your diffs. As far as the front goes, the same diff came in the Syclone/Typhoon trucks back in the 90's. They were turbo'd. The Sy/Ty forum shows these guys making sick hp and running the stock aluminum. If you're truly itching to upgrade, source a cast iron unit from a five speed 4x4 S-10. I have one that's going in as soon as I get my lovely Torsen unit installed.
The 7.625" rear end can be upgraded easily enuf with aftermarket axles. Just remember, because both of these units are " petite" the ring and pinion selection can have a profound effect on durability. It's been found that the stock 3.73 ratio is very durable. Once you jump to 4.11 or 4.56 the gear set becomes VERY small and prone to catastrophic failure.
So just some food for thought and go get em. Great project!

[mdmead]

Some day I'll complete this swap in my van... In the mean time...

A couple of sources for a relocation bracket for the A/C. I think the best route is likely the new brackets offered up by Holley. They seem to run in the $200 range, plus or minus. Holley actually offers up several different brackets to choose from. There is another company out there also making an affordable bracket, but I don't recall the name.

Regarding the trans, you need to figure out if you have an older or newer model of 4L60E. My '96 has the older version and requires a special adapter to install. Bought it at Jegs. It realigns the nose of the torque converter with the flex plate. And yes, one bolt hole (top of block? Don't recall) is eliminated during the bolt-up. (Isn't that important since the original trans didn't have it.) With a high-miles trans, you may just be better off exchanging for a rebuilt of the proper style.

Will be interested to see what you do about the pan and the motor mounts. I've had people on Facebook say the pan was not an issue for them, but I don't see it. When I've done test fits, it sure seems like it is going to hit. I've wondered if a H3 Alpha pan (5.3L and the sump is farther to the rear with more clearance) would clear... it's got to be damn close. This pan is available as a swap pan and I think Jegs and Summit offer it. (There are a lot of options out there, so it is crucial to find the right one.) Of course if the pan is an issue, it can be modified.

I've been trying to make a couple of sets of conversion engine mounts work together. I've got the JTR AWD V-8 mounts and I've been trying to use them with a 350 to LS mount. It didn't even come close the first time I tried, but somebody thought I had the LS coversion mounts backwards and after some investigation, they were right. (The reason I had it wrong was they didn't fit the other way. Had to grind on them a bit.) I don't know if I tried again to drop the engine in or not to see if it was a fit, or close.

Are you going to use the electronic throttle or keep the cable? I plan to keep the cable. You'll need a different (cable controlled) throttle body, but they are cheap to find on Ebay. (Some early LS engines used them. The reason I want to keep the cable is I think it will be easier to keep the cruise control and I don't want to deal with mounting the electronic pedal. (I've got one that came with the engine and it will require more fab work up in the footwell then I am interested in too.)

No matter what, you'll need the ECM tuned. If you haven't, sign up to an LS board and you'll find who people are using for affordable re-flashing.

Keep posting on this! I'm watching!

[racrx7]

Hey mdmead, lots of great info and much appreciated!!

So my van being an 03, I believe I have the later model 4l60. Seems I remember reading 03-05 started using a lot of 1500 truck parts. I'd like to find a 4l65 if possible. Just a bit more robust. Speaking of transmissions, are you leaving yours in the stock location? Using the same trans mount configuration? Can the engine be offset to the rear some for oil pan clearance? I ask because if I go to to an NP246 transfer case, the trans adapter required for that requires modification to the rear cross member. That being said, it can be moved around a bit.

How about exhaust manifolds? Stock? Certain body style ones? Shorty tubes?

When the time comes, I had planned on rolling out the whole sub frame to make the swap. Just seems it would be easier. I also will be doing some frame mods for the front suspension anyways. Much easier to work on when it's all out.

Got any pics of what you have accomplished?

Thanks again for the post!

[Astrophysics]

Awesome stuff guys!
Power to the Astro!

[mdmead]

Your trans should be the correct configuration. Seems like the change was actually in the late 90s.

Not sure on the manifolds. I think the factory (truck style which is what I've got) will work, but I didn't have the engine sitting exactly where I wanted to say for sure. Not sure what other options there are. Personally, I don't want headers, so I'd be looking for a different factory manifold. I'd guess there are some tight fitting header options though.

I'm actually moving backwards on my swap... I had the sub-frame out at one time, but a couple of years ago I had to put it back in so I could move the van from my Dad's shop into my own. Right now my 5.3L and trans are sitting on the shop floor with an engine-less van parked next to it.

Here is the last activity on my van... Sad for sure... Just too many other projects and a shop that is a true disaster area to work in. I'm trying to get organized though!

http://astrosafarivans.org/bb2/viewtopic.php?f=2&t=9371

It does look like I tried to drop the engine back after reversing the LS mounts and I still have pan clearance issues. I can solve my pan clearance issues by raising the engine up since I'll have 5" of body lift to work with, but I was hoping to keep this part all bolt-in. (This might also solve manifold issues. Raising the engine up does offer up more pan ground clearance which is a good thing!)

You asked about moving the engine/trans back... with the body lift, you may get a bit of room, but I think where the doghouse meets the floor is going to limit you.