vortec 454 swap into a 68 K20

[grass]

New to the page and to classic Chevy's, I have been searching for a couple weeks now for any info on swapping the drivetrain from a late 90s k2500 into a 67-72 Chevy k20 4x4 chassis, and I haven't really found anything. I have a 68 K20 with a mild 350 and turbo 350 mated to a np205. I also have a 97 K2500 suburban vortec 454 with 4l80e. I am looking at swapping the whole drivetrain from the burb into my k20. I'm trying to find a way to just bolt the 454 in, I'm not concerned with the cross member, I've built many cross members so that is not a problem, any help here would be greatly appreciated. Pics are what it looked like when I brought it home and how it looks now.

[ryanroo]

if not for the oil pan, the 454 would sit in the stock SBC position. i dont know exactly how the MPFI intake would affect fit, it may be close. i forget how far back they extend. the 4l80 will require some crossmember mods. the tcase from the k2500 wont work, and the 205 wont bolt up. you can get OEM 4l80 to 205 adapters, but they are quite rare. there are a number of places making adapters, but most are for the later model round pattern 205 case that i know of.

its a cool swap idea. ive considered trying it before in one of these trucks.

[DirtyLarry]

If it were me I would move the engine forward like the BBC sits in the 67-72 2wd trucks then use a later square body style trans crossmember to support the 4L80E. I’ve never been a fan of how the engines sit so far back in the 67-72 4x4’s. The downside to moving it forward would be the water pump would be really close to the radiator where you would probably have to run an electric fan as a fan clutch wouldn’t fit, or run a short neck water pump and run all old school v-belt accessory brackets and accessories (meh, I wouldn’t but it is an option). I also believe a 32 spline NP241 or even NP208 from behind a TH400 should bolt up to the 4L80E as well but I’m not sure what adapter would be needed. The 241 is a good alternative to a 205 if you have a difficult time finding one.

As far providing power to the engine, I wouldn’t recommend the engine harness from the donor Suburban. The best $600 you could spend on a late model engine swap is starting with a fresh stand-alone harness from someone like Howell Engine Development with all new Delphi connectors, etc. I have yet to see a reworked donor harness looks clean and is actually reliable. Think about it, a 1997 harness is almost 20 years old and you can bet most of those connectors are dry and brittle.

The entire method of a L29 7.4L swap isn’t much different from the L18 8.1L swaps I’m into. The L29 454 is a great engine, you’ll love it! Probably the best truck 454 ever built IMHO but I personally favor the 8.1L’s a bit more. A bird in hand is better than 2 birds in the bush. If I had a L29 in hand I would sure use it in something, plus those engines look sweet with the neat looking intake and clean valve covers (sans coil packs like unlike the ugly 8.1L)! Good luck with your project.

PS…ditch that body lift while you have it torn down. Body lifts are just plain sucktastic

[grass]

Thanks for all the info, I just acquired a 700r4-NP205 so as for doing a modern 4l80e I might just go with the 700r4. I'm really just looking to get something with overdrive because I commute about 170 miles round-trip for work. i'm sure I will end up driving the truck to work a lot. I was looking at the Howell engine harness and they are very nice, I am for sure going to buy one

[b454rat]

Something worth mentioning about swapping t-cases, you need one that has a VSS so the tranny will shift. 4L80/205 was used in ONE YEAR ONLY, that being a 1991 crew cab. Since I've been messing with trucks for close to 20 years, I've personally never seen one in a junkyard, and only one on the street. I believe someone is making the adaptor and tailhousing, but can't remember who it was. You could go with a 241 from a 91 suburban, that will have the VSS. 90 and older 241 and even the 208 will work with their adaptor, but no VSS. But I think you can take the tail off your 241 swap the parts over. Or, could swap to a HP44/60 from a 78/79 Ford, then wouldn't have to worry bout swapping t-cases.

Buddy took a Vortec 454 and put it in an early 80s 2 door Impala. Found a Whipple super charger, converted the car to 5-speed and seats from a 90s Bonneville. Guess is hauls ass....

[grass]

Auto meter makes a cable-vss adapter... had one on my 75 cj5 with a Howell fuel injection kit. worked great!!!

[Gobuffalo]

You can bolt a 4L80E to a NP205. It requires a little machine work.

http://67-72chevytrucks.com/vboard/s...d.php?t=640506

[grass]

well I have an update, I went to pick up a 700r4 on sunday and while I was at the guys house I noticed a ls motor tranny and tcase sitting in the garage. I asked him what the deal was with it, his dad said it was a 6.0 out of an escalade and he was just using the tranny and tcase. I told him to let me know what he wanted for the long block, he said he had no idea... two days later he text me $250 for the motor and to come and get it because he was sick of it being in the way in his garage...

[grass]

lq9

[argonaut]

Regarding for and aft engine position: I'm pretty certain that if you mount the big block in the forward position and try to use the long water pump serpentine setup it will not fit. Even electric fans will be very tight. So measure closely and take that into account as you locate and fab your crossmember.

I have heard that a 700r4 won't live long behind a big block or other high torque motor. I'm sure it can be rebuilt with stronger components but my understanding was that it was primarily used behind small blocks from the factory. If it were me I would just figure out how to use the 4l80e.

[grass]

SO I axed the 454 vortec, I picked up a LQ9 that is pretty much complete for $250 on wednesday

[argonaut]

That is a ridiculous deal on the LQ9. Awesome.

[grass]

Ya... as the guy said to me why would you want that fuel injected crap, wanted to start laughing my ass off. He then was showing me how bad ass his vortec 350 was he just put a carb on.

[grass]

well I installed a pacific fab ls cross member and mounted the LQ9, 2 days later a buddy caught wind of it and offered to trade a complete 88 crew cab dually for the LQ9, I had to do it. So I pulled the LQ9 the day after I finalized the cross member location. But before pulling the LS cross member I figured I would see if the 454 would bolt up... It did so that was a huge relief!!!

[Mr. 250r]

170 round trip? I thought driving an hour to work was kinda bad i hope it pays well to drive either a big block or ls that far lol. Assuming you want to keep the passenger side drop front axle mail ORD and ask them about using a 241 adapter a long time ago i asked them how to mate a 205 to a 4l80 and they told me you can use the 241 adapter i think you have to change the input shafts/notch the shift rails or something but nothing crazy.

[grass]

it pays descent, but I was just approved for a transfer to my departments office that is 3 miles from my house... only down fall is it will come with about a $800 a month pay cut. So I need to get the projects done before that happens.

[grass]

well the 454 is in, not pretty but in at least. Now I'm working on the hydro boost and hydro clutch, then I get to take it all out and paint it all up and make it pretty.

[70']

Did the 454 bolt up in the standard position on the motor mounts or did you have to move them to the forward position?

[chaff]

The savings in gas has got to be $400 a month + 3 hours windshield time a day, you my friend are a winner.

[grass]

The Pacific Fab cross member was mounted I believe in about the same location as the original sbc cross member, but the motor bolted right up to the new rubber mounts on the pacific fab cross member if that is what you are asking.

[70']

Was more curious about the back of the heads hitting the firewall. It seems to be hit and miss. I am really wanting to big block my 70 4x4 during my frame off, but don't want a bunch of fabrication headaches. Just taking a poll I guess. Thanks for the info

[grass]

Mine has plenty of room, the pacific fab cross member can be moved to where you need to not hit the fire wall.

[grass]

installed the Dana 70 rear-end, had to put on the dually wheels until the new tires and wheels show up

[PeterHall]

which rubber mounts are you using? we're also doing a 454 with 4l80e into a 72 k20. we're using small block mounts and flipped the crossmember to make oil pan clearence

[Farm Shop]

Any updates on this build? I'm curious about your 454... it looks more like a Gen IV with those valve covers and interesting accessory drive setup.