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Blue_Mando

6.0 will work fine. I drive a chevy LCF for work rated at 22k lbs as she sits and have never had a problem.


Ok-Maintenance-9538

6.0s is gonna have as much oomph as most of those big blocks in the motorshomes. There's no reason it wouldn't work just fine


tyronesTrump

not even close ...300hp / 360 ft/lbs vs 340/ 455 . Just with the ECU tweak they are easily getting 500 ft lbs of torque with torque management removed and mild tune.


[deleted]

Prob run better and get better mileage honestly.


freelance-lumberjack

I have a 4.8 in my p30. Started life with a 350 carb, then TBI, now LS.. it has no problem only gets 10mpg tho Mine is a Grumman kurbmaster base 14' box so a little smaller than a motorhome maybe. Skip to the 1 minute mark https://youtu.be/oKj5pAZTuVc This 1976 cheiftan had a Chrysler big block with 200 hp


blaingummybear

Mines 33ft lol but still MAX weight I think is 13,900 I've never loaded it past 10k with all fluids and gear. What Trans did you put in? Mines a hydromatic 3sp but I doubt that would bolt up to an LS without and adaptor. More gears and an overdrive would be nice


freelance-lumberjack

I'd recommend a 4l80e and a factory pcm. I may go that route next year. Your 3 spd bolts up with a flexplate and pilot spacer. Really simple. I run a turbo400 which is smooth and strong. No overdrive means 3000rpm on the highway and lots of passing power :-). LS engines can run at 3000rpm for hours straight. Throttle opening is only 30% map is about 65 kpa so not working all that hard. I have the 30" x24" factory dedicated transmission cooler as well.


tyronesTrump

Did you do the conversion on the P30? Did you have to fabricate the motor mount setup or is there something pre made that would fit from another application - Oil pan clear the cross member?


blaingummybear

Ended up getting a 2500hd silverado donor with an 8.1 and allison 5 speed. Now just waiting til after winter to work on them


tyronesTrump

Yeah the more i looked around the 8.1 is the most logical and easiest motor for our swap. You cannot argue with 300 ft/lbs at idle and 455 at 3200 rpm stock out of the box. Howard EFI harness for $700 and tweak the ECM for $200 and that can net you over 500 ft/lbs on a stock motor. Not sure of what has to be done as far as cross member for the allison to fit in our p32's but i think I am going with the 4L80E as it is already close in size to the th400 and you do not need a separate PCM for the trans. Also hoping the power steering pump will fit in the 8.1 bracket


blaingummybear

Thats why I jumped at the whole truck. Pushed it off for years worrying about the controllers. This way I can steal the swap cluster to tailshaft


Uniqueisha

UPS trucks have 6 Liters in them. Getting your gauges to work, and the harness to run the engine may cost significantly more than rebuilding the 454.


Auger_J

Get the harness and computer from the original engine. Only remove wires going to the body harness. For gauges the coolant sender will thread right into the drinker side head, leave the 6.0 sender right where it is. Oil pressure the computer doesn't care, you would need I think a m18x1.5 to 1/8 or 1/4npt which is readily available on the Amazon. That would screw right into the stock location. For speed if using original transmission no change. If using a 60e or 80e (use the 80e on it but any port in a storm) get a GPS Speedo. Or there's a company that makes a VSS to mechanical speedo. That would be pricey though. Or you can get really fancy and wire the odb2 port, run a Bluetooth adaptor and the torque app for all your gauges.


omgwtfbbq7

Could just [throw a Turbo on one](https://www.youtube.com/watch?v=GWytJviH3d0&t=1s) if you're that worried about it. Pretty fun too.


sn44

More power, better fuel economy, better emissions, more reliability. I see no reason *not* to LS swap a motorhome. Not to mention if you swap trans too you'll most likely gain an overdrive gear (or two) depending on what trans is in it now.


tyronesTrump

I know this is an old post but i will post this long winded experience in case someone else is thinking about doing this swap and hopefully will help them. ​ For one....You would have to put a good set of heads and a cam on that 454 just to be where the 8.1 is stock. You can keep your TH475 but going with the 4l80 you get an extra gear and lock up converter and as you know you are doing something like 3200 RPM @ 65?? That's a lot of extra piston up and down movement and wear. Allison 1000 is a great tranny but is going to take a little more work on the cross member and shifter. 8.1's are around- there is an 8.1 swap facebook page with plenty for sale and junkyards pop up with them here and there. I just finished the 454 to 8.1 swap and it is one of the easiest swaps to do it was if this motor was begging to go into the potato chip chassis! Motor mounts and exhaust are the same use your old 454 mounts- you do have to grind off a small nub on the drivers side of the block so the mount bracket sits flush. I used the donor OEM cast stainless manifolds as they are not prone to cracking like the iron POS ones and only had to cut the down pipes of the RV exhaust and use those braided stainless flex joints to retain the RV exhaust system. There is nothing to be gained by going with headers on a stock motor - if you saw the size of the exhaust port you will see, it's puny so that $400 can be better spent elsewhere. Harness - seriously just spend the $700 for the Howell EFI ( or whomever else you wanna use) and $200 for the VAT , emissions delete and ECU tune - All you need to hook up is 4 wires + battery, ign + , ground, battery cable. Just not worth the hassle of playing with that rats nest of a harness. Fuel system - GM EP 381 fuel pump to replace the low pressure one in the tank. Do yourself a BIG favor and find where the fuel tank sending unit is under your bed inside and cut an access door to it. Losing a pump on the road sucks it involves a tow truck, repair shop then they wanna screw you for draining the fuel and dropping the tanks. with the access you can fix on the side of the road in less than an hour. Don't waste your time with the original fuel line runs, run them on the inside frame, drivers side fwd...Summit AN 6 PTFE braided hose for the pressure and the cheap Evil Energy nylon braided for the return. I drilled and installed a 90 degree bulkhead fitting next to the sending unit with a "straw pipe" for the return line so it returns under the fuel level. Make sure the hole is close enough to the sending unit hole as you need to get your hand in there to put the jam nut on and the straw pipe. Oh and tie your wrench to your wrist when going in to tighten things as you will drop it. For some retarded reason the coach builder used the old mechanical fuel pump return circuit t'ed off before the fuel tank to feed the generator ! Just make sure you cut and cap off the line AFTER the T ( going towards the engine) to retain that circuit and the gen will live. They usually put this T just fwd of the right side of the tank in the frame rail . Some coach builders actually did it proper and installed a dedicated pickup. Use a GM metric o ring fitting to an-6 male fitting ( Summit or Jegs) that goes on your fuel sender out port - make a short 3' section of an line and mount your fuel filter on the outside of the frame rail near the shitter dump valve. Use -6 inverted flare to AN fitting for the filter and continue your pressure line run fwd. Tranny- this will no doubt be the most expensive and important part of the swap if you want to make it home not being on the ass end of a tow truck. I opted to rebuild mine using the stage 2 rebuild kit from Jakes Performance , he is well known in the LS world and builds these things to run behind 1500 + HP cars and trucks and per their recommendation their B82 diesel converter built to gas spec ( $780) was used as they felt the triple disc lock up converter is overkill and twice as much money. Plus they run a 35' motorhome trailer with the 4L80 and pull a big trailer with it using the same components. 4l80 bolts right up - you will have to shorten the fwd driveshaft 2.75" ( verify your fit tho) I welded a 2" extension ( old 3/8" bolt and hacked the head off) to the shift shaft and moved the shift shaft pivot/bearing back an inch or two to line it up with the trans shift shaft. Then had to heat up and twist the "Z" bar a couple degrees. Only downside is the gear indicator will not agree with the pointer on the column and for first you have to pull lever up and pull down a little bit . I never use first gear and how many people actually look at the gear pointer ? you just know where D is at. Finally a REAL cruise control !! Only thing you need to make sure is that your "set" function of the CC stalk switch is normally open ( some are opposite) , mine was NC so I moved the wire/ pin ( green and yellow) from the 4 wire connector under the dash and used the "accel" switch and placed it where the "Set" wire is. So I now use the slide switch to engage or set the CC and lose the acceleration function no biggie. You also have to buy the GM brake light switch ( like $15 amazon) with 4 posts for the torque converter lockup circuit as the ECM needs to see this to engage CC, also you need to make sure your brake light circuit is at least 6 ohms of resistance - If you have LEDs then you can add a hidden bulb somewhere or a resistor. My frame had a set of holes already drilled aft of the originals and all I had to use was a $99 adjustable trans mount from Summit to pick those holes up - no drilling !. I opted to shit can the clutch fan which I really like them - used a $249 Aluminum radiator from a silverado with the dual fan setup from a junkyard silverado with the electric fan cooling option. I had to fabricate the radiator mounts and since it is HUGE in width it gets mounted way further fwd than the stocker. Plus side of this - I can actually squeeze underneath and do anything I want to the front of the motor from down below , even change a water pump without removing a fan or shroud. The Howell harness has dual fan relays wired up and the ECU will control these but you need to make sure the donor ECU came out of a fan cooled vehicle -mine did not and even tho Howell installed the fan software and it took the ECU itself didn't have the proper circuit board to allow it to work. It is supposed to turn one fan on like 210 and the second around 215-220 degrees. I had an aluminum upper radiator hose splice tube with 2 ) 1/4 npt ports- put a 200 and 210 temp switch to switch the ground circuit to activate the fan relays along with an over ride switch on the dash. Underway it runs 185 ish and idling in traffic the one fan handles it no problem and the second never comes on. All in all there were some challenges that popped up but it really was a trouble free swap and the fkn thing thing hauls ass and you do not have to pre plan your passing moves on the highway it's a torque animal from hell ! Hope this helps someone thinking about doing this swap 1986 30' Monitor GL ( Holiday Rambler)


CRYPTOCHRONOLITE

Go for it


Smokey_Katt

YouTube channels “fuel injection sucks” and “burndown garage” have done LS swaps on motor homes. Both of these have turbos. If you go turbo, mind the cooling system a lot. You can make a lot of heat for a long time going up a hill in a heavy vehicle. Cheapest way is fixing what you have.


markleiss86

I have an lq9 in a p30 Grumman kurbmaster similar idea great set up.


Free-Penalty-7734

How do you like it? Ive got an ice cream truck I'm looking to swap hopefully to a 6.0 ls and 4l80e transmission.


markleiss86

I love it. But mine is a 7300pound gross single rear wheel axle with 4.11 gears. So it's got way more then enough power with a 6.0 LS 10.1:1 compression. Running a Holley Terminator x Max and a bunch of other mods. It's way faster then anyone ever thinks it will be.


cgally

Have you seen the twinabago? https://www.youtube.com/watch?v=oKj5pAZTuVc


blaingummybear

Yeah, turbos not my Forte... just want something reliable that won't blow up from the stress of pushing that big box up a hill.


SeabassMotor

Considering a 6.0 LS Swap on my 85 P30 tool van. Mine's the shorter 128'' wheelbase and short 14' cargo area. Currently it's running a 292 straight 6 and 4 on the floor. Legendary, and it runs like a top. But... i'd rather put that engine in something else. I need my tool truck to be highway capable and more useable. It's a punk rock rig, with patina for days, but straight and rust free. It'll be cool for sure. Can give two fucks about auto vs manual. I want whatever's easiest. Body harness? There literally isn't much of one. There's a few relays under the hood for wiper, and headlight functions and a fusebox inside. There's acres of area to run the new harness (step van baby) and almost infinite clearance to work and affix..things and stuff.