Chevy LT4 V8 Conversion for my Toyota truck

[JTR70]

This conversion is about 20 years in the making with the planning and collection of parts. Recent changes at my shop as far as storage has forced me to either move on this project or sell it off in pieces. I do need a functioning pickup again and I do miss driving it and in reality both the truck and its parts aren't worth a whole lot as far as cash value. Certainly the drivetrain isn't worth what I originally paid for it back in '97 so I've decided to finally build it and get it up and running as planned.

Here is how it looked about 8 years ago. It has the V6 engine and these early ones were notorious for blowing head gaskets. This one blew both of them about 10 years ago so here she has sat. I'd get about 3-5 notes a year under the windshield wiper asking to buy it. But its got a blown motor and its on a salvage title. Meaning: It ain't worth squat, other than its use to me as a truck and that I happen to still like it. So I never entertained any offers.

I'm not full size truck guy which is why I like this old beater so much but I do want full size truck power and..... sound. I bought this '93 LT1 small block complete way back in '97. It was a killer powerplant at the time but with the introduction of the newer LS powerplants and the passage of time it too isn't worth much. However, I own it clear so I'm going to put it all to good use. More later...
Thanks for looking!

Justin

[Don C]

Justin,
You're one busy guy! I get tired just reading about all your projects!
I'm sure this one will turn out amazing like the rest of your work, all the best!

[Gearz]

Should be interesting...

[JTR70]

Hey Don,

Yeah, I have way too many irons in the fire but I'm not doing this alone. My buddy Rick had offered to help me with the physical swap then its off to Utah this fall where my cousin David who runs a specialty speed shop will build the V8 engine and will interface all EFI and emission stuff along with plumbing for the A/C, heater, Power steering and brakes, exhaust etc. In the end it all has to work and pass SMOG. I'm not building a Hooptie, it has to be nice vehicle in the end.

Fast forward about 8 years and the desert sun has taken more of a toll on the old girl and my 35's (tires) long rotted away. A buddy of mine gave me some stock rollers to get it around.

Time to begin breaking it all down in prep for the new motor.

Interior all had to come out as well in anticipation for firewall modifications and any needed changes to the tunnel. I've built and rebuilt this truck 2 times over so I know it almost as well as my 356.

More later...

Thanks for looking!
Justin

[JTR70]

Transmission choice.

Like everything else I was on the learning curve and it took me some time to figure out exactly what my options where as far a transmission for this conversion. I only had two criteria that had to be met, it had to remain a functioning 4X4 and it also had to remain a manual transmission. An Automatic is nice but I prefer the fun and experience of banging my own gears especially with a V8! The go to outfit for these conversions is called Advance Adapters. They make all sorts of kits for various makes and engine/transmission conversions. The do make a bellhousing conversion for a Toyota trans to accept a Chevy motor but its designed for the Vortech V6 motor. You can run a V8 but the stock Toy transmissions won't hold up for long against the torque of a V8. Neither do the axles which will be the next weak link in the chain to be changed but they'll work for now. So the conversion kit I narrowed down to was for mating an NV4500 5-speed to an early 23 spline gear drive Toyota transfer case. This meant I could not use any of the existing 4X4 running gear already in the truck. The transfer case is completely different and is chain driven. I was soon on the hunt for a transfer case and a new transmission.

Eventually found this NV4500 trans in great condition from a '98 Chevy 4X4 truck. This was perfect as the bell housing is all set up for my LT1 motor. Would have really been simple if I could have just used the Chevy transfer case too but the output shaft comes out on the left side. Also pictured is the correct early style gear drive Toyota transfer case. New adapter housing is bolted to it in the photo.

This is one big heavy duty dog! Cast iron body with PTO outputs; this trans would also be found behind a Cummins diesel in a tow truck. Way more than I need for my little mini-truck but this is the only combination that they make a conversion kit for that fit my plan. What you see here has taken me several years to round up, paint etc. I bought those alloy PTO coolers just because I liked them. The other side won't clear the eventual drive shaft so I'll probably only be able to use the cap.

So with my causin David agreeing to help me with the motor I dug this all out of long term storage and began fitting it together in earnest. Only modification required on the transmission is to shorten the output shaft a little. That next..

Thanks for looking!
Justin

[JTR70]

Commitment time on the tranny.

Per instructions the output shaft has to be shortened just ahead of the splines that where once used for an internal dampener.

Wrapped the tranny like it was getting a hair cut and carefully zip wheeled the excess off.

The end was file finished and polished next.

Now able to mock it up fully for the first time.

The adapter housing has accommodations for a more forward gear selector. I'd figure this one out later.

Decided I wanted that selector as close to the shifter tower as possible for a more correct look and feel; That later.

Another requirement for this kit was a 23 spline output shaft gear drive transfer case. As I'd discover those where only found on the four cylinder Turbo version trucks. I faintly remember those in the 80's and they are sort of a rare bird. Most standard gear drive transfer cases have a smaller 21 spline which this one certainly had. The way around it was to buy a lower 4.70 gear set from a company called Trail gear which had the 23 spline output shaft as part of the kit. Problem solved, I'd have a lower crawler gear and most importantly it was now going to work with the transmission adaptor kit. A buddy helped me install this kit several years ago and one of the requirements was that we had to grind away some of the inner housing to get the new larger gear to clear. A potential problem is that this factory casting is very light and a few guys where experiencing cracking in their modified housing.

Advance adapters offers this heavy duty replacement housing machined especially for the larger lower gear sets.

I went ahead and ordered one as I figured I've got the extra weight of this HD tranny/drivetrain and the extra output of a V8. For 200 bucks it's just good insurance. Installing that next.


Fast forward several weeks and we are now over at my buddy Rick's shop who was nice enough to help me with this conversion. Getting back to that gear selector location change I wanted: I learned that Toyota made two different transmissions for this particular transfer case. An EFI version and Carbureted version. The Carbureted version has the more forward selector location and I of course had purchased an EFI version. Fortunately the transfer cases are Identical and its as simple as just changing the shifter rails. You can see the new shifter rails with the claw ends poking out of the new housing.

Done! New HD housing and shifter rails installed.

Original EFI shifter location gets a factory cover plate. Now ready to install this for good on the tranny.


Thanks for looking!

Justin

[JTR70]

A long history and a few incarnations for this old truck.

As with all my earlier car stuff my dear old friend and mentor Greg Parker had a hand in helping me find and build this old truck.

It was offerd to me as an abandoned rebuld project. A '92 extra cab 4X4 that belonged to a guy Greg knew who fell asleep at the wheel and rolled it. Didn't see the truck before hand but I was told it was White with blue interior and very nice with a 4 inch lift. Lift is still with the frame here but the larger wheels where now gone.

Donor body was an '89 2WD theft recovery that Greg sold him for the rebuild. Eventually the owner lost steam and decided to buy a new full size truck.

Greg knew I was looking for one so it was offered to me as a package for about 2,500.00 bucks at the time (1994) which was a pretty good deal. It was great jumping off point so I snagged it immediately.

The donor interior was blue so I thought a dark metallic blue would compliment it better than the original black of the donor body. My Dad was still painting cars then so I hired him to paint it for me. I remember the night I took these shots. I was so excited as we had just put the body on the frame which already had my new rolling stock mounted.

Shot of that trusty V6 I had also repainted the frame and chromed some of the suspension pieces... I was a nut. but the stupidest move was yet to come.

After several years of trouble free service the V6 began to loose performance (head gasket) so I parked it. While it sat I got the bright idea of making it a full on off-road pre-runner truck. Part of the disease from hanging out with bunch of guys who are involved in that world I guess. So I blew the truck back apart sold the 4X4 chassis and mounted the body back on its 2WD frame in preparation for a full cage and long travel suspension. Don't ask me why I didn't just buy another bare body to begin this project. Stupid things a 20 something year old does who couldn't see past his nose is all I can say.

Its all teed up here and was ready to go to my buddy Warren's shop for the full treatment. Problem was, Warren was really backed up with race car fabrication and prep and one year quickly turned into 2 years and here it languished in Greg's impound yard waiting for its turn. Also pictured here is the same LT1 engine I'm finally putting in now so this is not the first time I've attempted to put this motor and truck together.


As I waited my turn my priorities where changing once again. I was getting interested in my old Porsches and realized I needed a truck more than a pre-runner. What also sealed my decision was the arrival of this little beauty to Greg's yard.

It was a 1990 V6 which belonged to a GI's wife who was stationed locally at the time.

The story was she went out of town and gave her husband strict instructions not to driver her truck. Well he didn't listen and decided to have some fun with it out in the desert. By 2001 it was easily totaled and Greg ended up with the wreck. As soon as I saw it I asked Greg how much and we made a deal.

Began swapping everything over(again) to recreate what I had previously screwed up trying to get back to even. Bought a new 4 inch Procomp lift to run my 35's.

I distinctly remember berating myself during this rebuild about the stupidity of tearing apart my beautiful old truck. I asked Greg why he didn't stop me and he said "you weren't going to listen, you had your mind made up, somethings you just have to go through and discover for yourself". He was such a wise man, I miss him everyday.

So this last incarnation got me about another 7 years until its V6 gave way in 2008. Now another 10 years later a little older and hopefully a tiny bit wiser I'm going to complete this motor swap.

Thanks for stopping by!
Justin

[JTR70]

First little glitch. These factory shift forks don't reach down quite deep enough to where Advance adapters has drilled and tapped the base holes. I couldn't reach and engage 4 High completely. First thought was to move the base back to center over the forks. We drilled and tapped new holes and I shaved some of the back shoulder of the housing to allow for more movement. After all that it still wasn't enough. This was full afternoon so defeated I went home.

After some time thinking about it after dinner I decided that the best approach was to add more length to the forks themselves. Rick wasn't really sure about this approach but I said that I don't care what they lookd like, they just have to work and do their job. Besides the whole point to this was moving the selector forward. Forks pictured there with an additional quarter inch added. That turned the trick and worked perfectly with base in the original holes. Felt bad about the additional holes and grinding that I did. Wish I would have come up with this first but it won't really mater once the base is on for good. Problem solved anyway.

Transmission and transfer case fully sealed and bolted together as unit.


Really neat to see it all together after all these years of planning and parts collecting.

It was now time to bring the truck over and remove the old drivetrain and make ready for the new. That next
Thanks for looking!
Justin

[JOP]

Heay Justin,

I think you made a mistake with ya frankenstein hauler
You NEED ONE like this
Thx 4 sharing your journey on 4X4

[JTR70]

I think you're right Per. I'd build one of those next and put this truck on its back

Getting her ready to accept the new drivetrain.

To make everyone's life easy the core support and inner fender liners where removed.

We just plasma'd them off at the firewall where I had cut and rewelded them back on all those years ago. Before its done I'll fabricate new flanges with capture nuts so this entire front assembly will remain removable for easier service of this larger V8 engine. Actually its not larger than its old V6 only just slightly longer as I'd later realize.

Out with the old

Prepping the chassis itself next.

My buddy Rick plasma cutting the old motor mounts off.


Cleaning up the remaining slag

Surfaces all clean but we'd eventually have to cut past those platforms and into the actual frame rail to have enough room for the now mounts.

Time at last to join the motor to its new tranny.

One Looong assembly.

Time to find out whether this is all going to work or not Fitment into its new home begins.

Thanks for looking!
Justin

[Don C]

Wow, no safety glasses?

[JTR70]

I know it Don, I asked him the same thing as I brought my own glasses and hearing protection over to work on this. He's been doing this long enough to know better but he's a big boy...

Justin


Got the new drivetrain sitting in the Sweet spot.

As we jockeyed it for best position the first of several obstacles quickly made themselves known.

This rearward axle mount is in direct interference with the bellhousing and the eventual starter motor. I'm running the suspension lift and you can see the drop brackets that came with the kit. By Cutting this mount free and eliminating the brackets I can easily remount it lower and hopefully out of the way. Will know once the entire motor is set up.

But for now it just needed to go. The other side would also have to go.
Par for the course with custom retro fits.

With that mount gone the motor really slipped into place and at a really nice angle. I mocked up the water pump for a more accurate final length and to see how far it was going to intrude into the core support. With most of these conversion the radiator must go forward and you end up losing the hood latch. I'm trying desperately to avoid that and at first glance I think I might get away with it.

As for engine height the front of the oil pan just has to clear the steering link. The motor is spaced off it here in about its final position.

Other clearance concerns: Surprisingly good clearance with tunnel and bell housing. Worst case scenario would have been a required body lift but I was desperately trying to avoid that too.

Plenty of room down here and to develop a new axle amount and/or position.

What was most relieving was to find the shift towers in nearly the stock position save for they are a touch wider apart. So glad I moved that rear sector forward . My initial measurements had the shift tower a lot more forward than this but much to my great relief its almost equal. I was getting worried it was all falling into place a little too easily.

With all these planets in near alignment we began building the new front engine mounts.

Thanks for looking!
Justin

[JTR70]

Further motor mock up and a few minor but expected clearance issues.

Welding in the new motor mounts

Engine now mounted with good clearance oil pan clearance.

Now time to mock more of the engine up with heads and intake.

BTW: this motor started life as an LT1 from a '93 Z28 but being as I can never leave well enough alone I found this complete factory NOS GM LT4 upgrade kit on Ebay several years ago. So once David has completed the rebuild it will be a nice healthy LT4 as what would have been found in the '96 Grand Sport Corvette.

Interference with the fire wall immediately cropped up on the right side with the head and valve cover.

Left side fits beautifully so far.

Head and valve cover encroach into the embossed relief for the A/C evaporator box.

A quick relief was added so we could keep going. I'll go back and address this later. Also below this cut the lead corners of the tunnel hit the bell housing so they'll have to be reworked a bit.


Same story on the drivers side but nothing really serious much to my great relief and surprise. Again this will be a clean up detail I'll fix later.

End of the water pump is damn near even to where the end of the original powerplant sat. Really pleased with the position and fitment so far.

Onto the next challenge of exhaust manifolds. I thought it Looked so good sitting in there
Thanks for stopping by!
Justin

[JTR70]

New drivetrain fully mounted in the chassis.

Upping the ante with the more parts. Exhaust manifold will require some additional clearance with the firewall and so will the eventual emission system I can tell already.

Brake lines will also need to be rerouted but just enough clearance in to run a pipe through there.

Left side will require much more work as I couldn't even mock it up. This side dumps out the center and collided with the torsion bar.

The other axle mount down below there will also have to relocated. I'll deal with all that later...

Could have been worse..

transfer case/ mount sits farther back so the original crossmember could not be reused.

Fabricated this tubular version which utilizes the original mounting location

And stock mount. Don't know if I'll keep it as is or change it as the conversion progresses but it at least holds the back end up where it belongs.

What I am most shocked and pleasantly surprised with(not to mention grateful) is the clearance I have in with the tunnel. I always thought I was going to have clearance issues with this behemoth of a transmission. I was prepared for either a body lift or major surgery on the tunnel to get them to clear but fortunately neither where required .

Can't keep the cooler on this side of the tranny due to the eventual drive shaft but it keeps it sealed from the elements for now.

Thanks for looking!
Justin

[JTR70]

Truck back at my shop to finish out the rest of the sheet metal modifications.


Mocked up with inner fender aprons and core support.

Old radiator installed to check for final distance with the water pump. This won't be the unit I'll use but it represents a close approximation.


Plenty of room for an electric fan assembly.


The significance of this is that the radiator doesn't need to come forward to make way which means the hood latch stays intact. A lot of these conversions I've seen required it and its more of the norm rather than the exception.


The new motor is longer but as you can see its significantly shorter than the old motor with its Plenum and dual overhead cams.

Sheet metal work begins next.
Thanks for looking!
Justin