Leedogg

iTrader: (2)

I have searched to no avail....but I have a 89 crew cab dually with a TBI 454/th400, that I am considering a 6 liter carbed setup with a built 700r4. I was thinking that a stock carbed 6 liter packs prolly 100 more ponies- but about 100 less in tq. gear can make up for that, with an OD trans.

Anyhow- anyone in here using a LX motor is a tow pig? Are there any mods to boost TQ over HP? It'd have to get better mileage than a 454.LOL

ZONES89RS

iTrader: (25)

Man, I bet a stock 6.0 lq4 with a ls1 cam to bring rpm up a bit would work bad *** for the long block, then performer rpm manifold topped with a vacuum secodary 750 would do magic honestly.

The tq band will bitch slap any old small block, the efficiency by itself would be awesome, get a lower thermostat, a set of cheap shorty headers to tip it off with a y pipe, I think it would be great man.

3pedals

iTrader: (3)

I agree

xpndbl3

iTrader: (23)

towing and 700r4 trans LOL....just toss in the motor, keep the strongest trans GM ever designed in your tow vehicle and run it. You'll be up on HP and TQ along with increased fuel economy. No reason not to drop the tank and toss in a walbro 255 or similar and keep the EFI for a tow vehicle though. I'm doing the same swap in a 88 lifted suburban that I tow with.

NemeSS

iTrader: (127)

Ithink I'm gonna vote Efi on this one.
My 00 rcsb does fine towing and gets 22-23mpg on 87octane. And all it's got is a lowly stock 4.8 with 60e
Only upgrades are diy cai
Summit trans oil cooler and deeper cast pan
Gm engine oil cooler lines from HD truck with summit oil cooler

ZONES89RS

iTrader: (25)

I can tune my own carb, so i say carb if it is carbed, otherwise, if you know how to do it, then the EFI ic pretty cool, but i dont know how to do all that.

NemeSS

iTrader: (127)

Yea might as well carb it
That tbi is no better than a carb anyway. If anything mpg and Hp will prolly improve with a well tuned vacuum sec carb.
TBI and the horse it rode in on

ZONES89RS

iTrader: (25)

Lol, not to mention the lack of top end a tbi system cannot hack.

3pedals

iTrader: (3)

yeah, I overlooked the 700R part of the OP. I would NOT swap to that either.1 word for that trans : FRAGILE!!
Keep the TH400, Just make sure you gear the truck to work with your non OD trans. As posted above, thats the strongest trans you can get, and when your towing you dont use OD anyway.

68vette

Go with the 6.0l. There are some upgrades that can get the torque much higher than what the 454 came with in 89. Horsepower will be much higher as well. In an 89 454 you are looking at 255 horsepower @ 4000 RPM and 405 lbs-ft of torque @ 2400 RPM. A bone stock LQ4 or LQ9 will get you close to with 360 and 380 lbs-ft respectively. Put a carb on an LQ4 and out of the box you will make big torque. Car craft did some dyno numbers on an LQ4 with just the carb setup and with the carb setup and a cam. The carb setup alone made no less than 400 lb-ft of torque from 2,200 to 5,400 rpm and managed to crank out a peak torque of 439 at 4,400 and 425 hp. when they added GM's Hot cam (a good cam, but there are better cams for even more torque) torque went up to 450 lbs-ft and horsepower was at 483.

hornerhotrods

iTrader: (2)

I suppose you were talking about the stock efi that comes on the motor correct? Not a lowly pos tbi setup right? The Efi would be much better suited for the towing and part throttle driveability than a carb setup. Its all in what you prefer

xpndbl3

iTrader: (23)

yes i'm telling him to remove the stock tbi and put on the factory gen3 setup. Just toss in the high pressure pump and reuse the factory tbi lines with adapter fittings. Remove the tbi computer and you'll have power, ign hot and grounds for the new computer already ran through the factory fuse panel....doesn't get easier than that

hornerhotrods

iTrader: (2)

Cool that what I thought you were saying. X1 for easy installation

Leedogg

iTrader: (2)

I am thinking the 700r4 cuz I alread have one that is built in my 92 silvy. I am considering turning the silvy into a race truck(has a salvage title), and I could drop the 400 in it for racing. The dually will only tow my Trans Am, or RCSB Silvy on a open trailer. I figured the 700r4 would hold up to that...maybe not....

Thanks for the info everyone. I just bought the dually for a tow pig...and it has a random miss I cant figure out. gets 9.5mpg(which I expected)...so I started wondering about the LS swaps. The wiring in the truck is not in as good a shape as it could be- Like to go carbed and ditch the wiring.

Leedogg

iTrader: (2)

Also you guys are saying simple swap to efi...any links to similar installs.

xpndbl3

iTrader: (23)

no i wouldn't tow with a 700r4 at all, buy another th400 for the "race" truck if you feel the need, they're cheap to buy used. Conversion forum and search for the truck swaps, there's like 40 of them

Leedogg

iTrader: (2)

cool- I'll go do a search.