LS engine swap info

[feller]

hummm... thanks man

[89 crewcab]

what swap would get me the most bang for the buck in a 1989 3500 4x4 crew cab RV puller? I like the Cummins idea but that = mucho $

[Firebirdjones]

Are you looking for pulling power or gas mileage??

When it comes to both, it's hard to beat a turbo diesel. I just can't justify the cost so those are out of the question for me.

I use a 79 1 ton for pulling my 28 foot enclosed. The 454 was getting tired so in my case it made more sense to rebuild with a stroker crank (aka 496).
The old 454 would get 14 mpg highway with 3.73's and a 400 turbo. I lost some of that with the 496 but I was after more towing power for the hills around Arizona. It's all a matter of what is more important to you.

[89 crewcab]

It has a small block 5.7 stock engine now, best of both worlds. You know, no power AND bad mpg's. I dont expect to get better mileage out of a stroker (383) or a big block but my 30 ft toybox only allows 25 mph on some grades with the stock engine. I have heard a lot of praise to the 383, but how much more work/money would it take to swap to the 496? I have a turbo 400 trans in it now but I also have a Getrag 5 spd I could have swapped in. I am looking for pulling power more than anything, but dont want to get too many $ wrapped up in it.

[Firebirdjones]

Hmm, I'm surprised an 89 3500 crew cab would come with a 350 for an engine.

Swapping to a bigblock is a pretty big chore if you don't have a donor truck to start with. Every bracket and accessory is different, that's not even getting into all the computer controls and tuning differences.

My old 79 is a factory 454 1 ton, so it was already there, when it was time for a refresh the 496 stroker just seemed like the next logical step for me

If I were in your shoes and didn't have a donor truck to steal from, I'd stick with the small block package and maybe look at some of the crate engines like the HT383. Or if you know of a reputable machine shop then stroking the 350 to a 383 is cost effective. Actually it's about a wash when it comes to rebuilding one anyway. That's probably the least expensive way to go if you dont' mind some down time.

[89 crewcab]

thanks for the reply, I wondered what was involved with the big block swap. Do you have to change fuel delivery when you go to a 383 or will the tbi that is on it now be sufficent?

[Firebirdjones]

I tune carbs and newer LSx fuel injection stuff, but the throttle body stuff is an older design that uses a computer chip and completely different software.
I used to tune tuned port injection stuff which used that software made or sold by Moates, of which I no longer have.
At the very least you would have to find a place that can reflash your E-prom so it's more suited for the fuel and timing requirements of the 383. Other than that, in a nutshell what you have should transfer over and work.
TPIS is one place that comes to mind. Arizona Speed is another. They both still tinker with E-prom style computers as well as design and build intake and fuel systems for this style fuel injection.

[thor]

Just tossing out a different idea - How about lower gear set for the TH400? Many manufacturers make a 2.75 first gear and 1.57 second gear for the TH400, as well as the 4L80e. This could get your mass moving better. But, if it's cruising speed your after, then I agree, you need a heart transplant.

A stroker motor would be the cheapest and easiest route since you already have a small block in place. However, big block will give more grunt. A 454 would probably be the next "cheaper" step, but like stated above, it would be easiest to find a donor vehicle for all the parts you don't think of until things don't line up quite right. But to tempt you even further, perhaps an 8.1L would be fun. A 496 with fuel injection from the factory. But I think we've blown the budget by now. So back to the 383.

Just my .02

[89 crewcab]

I thought of the 8.1 but would'nt you have to intall a computer or something?

[thor]

Yes, you would. And that brings other headaches, challenges, or opportunities to learn new stuff, depending on your outlook. I'm also not sure what the "recyclers" are wanting for them. Easy + cheap = 383, me thinks.

[89 crewcab]

thank you for the info

[bigboyitm]

I have probably over looked it, but I have looked. I am looking for a DIY on the mods that need to be done to the wiring harness for an LSX. I bought an entire truck that I will be pulling the motor and tranny out of, 04 2500 Truck LQ4 4L80E.

[thor]

Check LS1tech.com for wiring diagrams and such. Unless someone posted on here and I missed it.

[usmcchevy]

www.LT1swap.com I referenced that site, but also end up using wiring diagrams from all data.

[structures]

I got all my wiring diagrams from autozone.com under the repair manual section and referred to the guidance provided on www.LT1swap.com. But I don't actually have a running engine yet.

[fpjr0]

my .02 I got all I needed when I did my 5.3 swap from the lt1swap page mention above...it took about a weeks worth of studing the diagrams and reading on the web and about 6 or 7 hours of actually cuting and re routing the some wires \.

[aggie91]

suscribed so that I can find this one later...

[K-TEN]

Great thread and thanks to all.
I'm putting a 4.8 and 4l60e from a 2000 truck into a '51 GMC suburban. It looks like it all fits pretty well except for the pass. side exhaust manifold. I need something that is shorter or longer, to get by the top of the frame rail. What would be a better stock ex manifold?
Also, the engine leaked out orange anti-freeze. Can I run traditional green AF in this motor without any issues?
I broke one manifold bolt, but it'll come out. What is the least expensive but proper replacement for those? This is a major league cheapo build. And I'm sure I'll have plenty more questions. I got the motor trans and redone harness for $1400 bucks. Which is cheaper than rebuilding a 6 banger. Thanks again..

[Thealien]

You can run regular antifreez (I would try to flush all the dexcool out though)

Prestone (others might also) Makes a universal antifreez that is supposed to work with both types.

Some people use Fbody (camaro/firebird manifolds 1998-2002?)

I am using trailblazer SS manifolds that hug the block nicely (but mine is 4 X 4)

I would just get some manifold bolts from a dealer, parts yard? I use copper never sieze as they are prone to breaking. I use a torque wrench also.

Good luck with your swap

[K-TEN]

looks like Dorman makes a TBSS or SSR manifold for under $100. p/n 674785 or maybe the 675525
Do you run washers on the manifold bolts as some are suggesting?

[Thealien]

I didn't as I used stock manifolds and stock bolts. After installing everything and hearing how many have had broken exhaust bolts so a month ago I removed every one and put high temp never seize and reinstalled and torqued every bolt except the couple I couldn't get the torque wrench on.

[Firebirdjones]

I used the stock bolts as well, which don't need washers because they are already a shouldered bolt.

I install with antiseize which is common practice for me with anything aluminum. Steel bolts and aluminum parts don't mix well.

I used the 3/4 ton truck manifolds on my swap, they are said to be some of the better flowing manifolds out there as far as trucks go. I had to slightly notch the frame however because they kick out a bit, which is what helps them flow as well as they do. I sent mine out to be extrude honed as well.

[K-TEN]

Who knows about stock exhaust manifolds? The original truck (2000 4.8) manifold sits just above my frame rail. I'd like it to be shorter by at least 2 inches, or if it tucked tighter to the engine by about 2 inches. I'm looking at the SSR manifolds. They SEEM to be shorter, but I have no way of knowing at this time. Dorman has the repros for about $140 or so with the gasket and studs. The GM Dealership can get me a new GM part(SSR pass. side ex manifold) for just over $80 bucks. (No gasket or studs).
Can anyone tell me if the SSR manifold is actually shorter than the original truck manifold? Thanks.
(1951 GMC suburban w/ 4.8 and 4l60 and '65 truck 12 bolt going in)

[grennberet02]

Started my LS swap and the 98 camaro exhaust manifolds did not fit using the transadapt plates and the stock motor mounts.
I may be using shorty headers instead for the exhaust set up.
Plenty of room near the rear of the motor.
I broke one of the rear coils as it hit the brake booster. (accident)
You may think of removing these before installing.
I used a Poly mount with a single stud in the middle and only had to move the engine mount to the rear using one of the existing holes.
The drive shaft will need to be shortened. Using one from a burb.
Just wanted to add this to the list.

Thank you,

Luis G.

[Clyde65]

I used the Sanderson Shortie Headers CSLS1 and have not had any issues at all, no leaks not fitment issues at all.