🔧 BUILD Turbo 3800 T56 Swapped G-body Grand Prix w/ Holley EFI

[bs009]

i wouldnt worry about the l36, ive had two l26's (the weekest 3800) and pushed them over 500whp in a grand prix one of them had a cam and double roller 130# valvesprings and every other part was stock in the long block including the head gaskets and head bolts 17psi almost every day for a whole summer

I would like to argue that the L27 is the weakest lol.:mepoke:

But regardless, it's good to know though. This makes me feel extremely comfortable with putting the snail on it!

 

[Mr_Roboto]

Thanks for the link! I'll have to think about it. It'd be weird to have the camaro discs in the rear and the stock g-body 10.5's up front. I'll probably see if I can find a way to make my own mount and swap them over.

Google for it, there's a LOT of templates out there for the A-body ones at least and I think I've seen em for the G cars. It's not exactly hard to make regardless, I just didn't quite have the gumption or a drill press to. It's more that even if you don't use the parts you can recoup at least part of your investment in the parts car with em.

Good choice on boxing the frame. I really want to do my Lemans eventually, but I've got a ton of other stuff to do. The A-bodies eventually got bracing for the LCAs in them, I'm somewhat surprised the G cars don't have it too. Maybe they beefed it up some or the power went down that much?

Man that rot SUCKS. Unfortunately it's likely you'll find more if you found that and you're stripping it. Just sorta goes with the territory.

 

[Euro]

Awesome progress so far!

 

[bs009]

So I've finally gotten around to digging up this project and picking up where I left off. I've made some progress this weekend and hopefully it will be running and driving in time for the Michigan meet. It'll be close on time since I have very little free time lately.

This weekend was the start of the frame modifications. I'm using Hellwig's frame FX kit for the frame since I don't have time to be cutting and bending tons of metal to fit up to the car. So here it is:

And the metal I'm using to modify it:

From the factory these frames aren't welded very well. Gotta give them credit though for doing this with robots I guess.
Here's some examples of how poor the welds are from the factory. I've cleaned up a lot of the sticks that were left on the frame and the bumps from the welds.

Welds so good the blow right through the metal...

And cleaning it up:









So here's the first side tacked on. Notice how much further that lip is extended now and how the frame is boxed outside of it. It already feels stronger even though it's only tacked on.

And finally the passenger side is tacked on too:

And for fun; this car's frame is ~33 years old and this is the worst of the rust I can find on the frame:

Hopefully I can finish welding everything up throughout this week. Then I'll be moving on to the area above and behind the axle to help strengthen those areas. The final touch back there will probably end up being a hitch since the frame will be so strong once I'm done I could haul stuff with this thing. The hitch will also help to strengthen that rear up a lot. After that's all done it'll be getting the POR-15 treatment!

 

[yjmud]

easy brake upgrade for that thing is the dual piston set up from a 2x4 s10 plus that opens up for other brake upgrades later. Are you going to change the tail shaft housing on the t5 to relocate the shifter to more of a mid shift with the s10 tail shaft housing(just remembered with that bellhousing you have to run the trans the way it is)

 

[Yaj Yak]

this is neat.

 

[daturbosix]

how do you plan on getting the lower half of that center body mount in when you just boxed up that area of the frame?

 

[bs009]

easy brake upgrade for that thing is the dual piston set up from a 2x4 s10 plus that opens up for other brake upgrades later. Are you going to change the tail shaft housing on the t5 to relocate the shifter to more of a mid shift with the s10 tail shaft housing(just remembered with that bellhousing you have to run the trans the way it is)

Thanks for the heads up on the s10 brakes. I've thought about going with the s10 spindles and and bearing packs but I don't really want to have to deal with paying for new bearings or digging through the junkyard and hoping the bearings I get are good. I've been eye-ing those aftermarket aluminum spindles, but they want too much money for them.

The parts Camaro has 12" brakes up front with dual piston aluminum calipers so I want to just swap those over. I'll have to figure out whether I should get S10 bearings or find a way to turn the original rotors from the Grand Prix into hubs. I'm gonna dig for those templates that Mr_Roboto was talking about. That'll save me like $80 right there.

As far as the transmission I was originally going to go with a Tremec TKO 600 and have them send me one with a midshift kit installed, but since time is becoming more of a factor here I'll have to go the S10 route.
I've never taken apart a manual transmission though so that should be fun to shift the linkage and tail-housing over.

how do you plan on getting the lower half of that center body mount in when you just boxed up that area of the frame?

Good call on that one. For some reason I thought the hole on the bottom there would be big enough to get everything through. Now that I'm looking at it though it's the same size as the one on top.
I think I'll just drill out the bottom hole so I can fit the washer and bushing through.

 

[daturbosix]

the bottom portion of the frame is smaller than the bottom portion of the bushing.

 

[KnightFan26917]

The car is my 1982 Pontiac Grand Prix Brougham.

Wow ... nice car for a great project. Like that color combo.


Cort OLD CARS, STRONG HEARTS | memories, even if the whole world has forgotten
1979 & 1989 Caprice Classics | pigValve, paceMaker, cowValve
"It seems to have a vague, haunting mass appeal" __ Incubus __ 'Drive'

 

[Mr_Roboto]

The caliper mount is integral on the spindles you have I believe; you'll need the Blazer spindles regardless of what brakes you do. I believe the C5 plate diagrams will work for the Camaro calipers provided you use their abutements. Be sure to measure though, disclaimers apply. Even the Blazer brakes are a good upgrade though and you get the benefit of sealed bearing spindles too.

 

[bs009]

I'll have to get a better look at the spindles then. I'm planning on going to the junkyard this weekend so if I see 2wd s10 spindles with bearings I'll probably grab them.

So I'm trying to decide what clutch I need to get. I was planning on going with a Spec stage 3+ but that's mainly because I don't know of any other options other than Spec that I can use for a T5 and 3800. I know the 3+ is supposed to be streetable, but I've heard mixed reviews of it.
I'm going to be switching over tailhousings on the T5 this weekend since I found an S10 trans, so I might be able to acquire and swap the input shaft for one of the better v8 shafts while I'm at it. I've never dealt with manual clutches though so I'm not sure if I would be able to use a clutch from a v8 car with the 3800. There's probably some issue with space between the input shaft and the flywheel?

Does anybody have any input here?

 

[Jfrost]

The Spec Stage 3+ is one of the go to's for swapping this same type of engine into Fiero's. I'd say you'd be just fine running that in your application.

As far as the flywheel is concerned, I'm not sure if you'll have to trim it down for your application or not. I know for Fiero's since we use a flywheel for an f-body we need it machined down to .840 for proper clearance. If you use the drivetrain that's from an f-body I figure you should be OK.

 

[bs009]

Wow ... nice car for a great project. Like that color combo.


Cort OLD CARS, STRONG HEARTS | memories, even if the whole world has forgotten
1979 & 1989 Caprice Classics | pigValve, paceMaker, cowValve
"It seems to have a vague, haunting mass appeal" __ Incubus __ 'Drive'

Thanks!

Okay well I pulled the trigger on that Spec clutch. As far as the engine and transmission go with the clutch, it's still a factory replacement clutch for the 98 Camaro only it's a stage 3+. Fitment shouldn't be a problem unless I were to switch input shafts; based on what I've gathered the v8 shaft is a different length.

I've been working on welding the rest of the frame this week. I ended up popping out the squares below the center frame bushing hole so I could get the bottom of the bushings in. I figured I'll never need to replace them again since I got poly bushings for it. Thanks for the heads up on that one.

I'm picking up the S10 transmission tomorrow so I'll probably start on swapping the tailhousings after the frame is done. Hopefully I can finish my work on the frame and get ready to POR it by the end of the weekend.

 

[bs009]

I finally finished welding the frame FX kit together. This was actually my first welding project so a lot of it isn't very pretty, I feel like I've gotten the hang of it now though.
Boxing those c-channels seriously made a world of a difference! This thing is STRONG now!

I continued to add some bracing in the rear above the axle. I can't believe how much of a difference adding 4 small pipes has done. I am absolutely amazed!

I also picked up a transmission from an S10 so I can use the S10 tailhousing so the shifter is farther forward.

Turns out that this thing was kinda rusty inside so I've got the tailhousing and the top plate for the shifter sitting in vaporust right now. They should turn out just fine though.

I also finally got around to checking fitment of the engine, transmission, and driveshaft.
It looks like I can re-use my old driveshaft and I also won't have to move my transmission crossmember. However, I'll need to find a different route for engine mounts. The mounts I used for the L27 won't work since it appears the series 2 3800 is about 2 inches wider at the motor mounts.
I'm thinking of using something like the Camaro used where the bushing is in the frame mount and just making my own mount on the car. Perhaps another excuse to hone my welding skills. :banana:

Driver side bolted in with old mounts:

Passenger side has no room:

And finally we have the engine and transmission taken apart here:

The engine isn't getting anything special at this point. Just manifold gaskets and some PNP. The transmission is awaiting its new tail-housing and shifter.

Next weekend I'm hoping to have the frame painted and ready to bolt to the body. That also means getting all of my fuel lines and brake lines installed too. Also I'll hopefully have started on my engine mounts so I can finally knock that part out. The most time consuming part will be wiring everything together and modifying the body for the 3rd pedal and the shifter poking through the floor.

 

[Mr_Roboto]

Love the boxing. Would love to do this to my Lemans. Supposedly one of the best things you can do for rigidity. I wish it was easy like yours where the trans crossmember is outside of the frame.

 

[Turbocharged400sbc]

the oem 3800 F body mount brackets fit both the SI and SII blocks and fit the v8 style clamshell mount configuration

 

[bs009]

Good to know. I must've found a way to make the s1 fit squeeze in there somehow before then. I always felt like I was putting too much pressure on the motor mount bushings.

I've decide I'm going to make my own this time. I'll get some of the clamshell mounts that have bushings in them and then cut and make my own engine side motor mounts I think. I don't think I'll be able to find anything that just bolts up.

 

[OffshoreDrilling]

First time in this thread, digging the project. There have been a lot of unique builds on the forum lately, this definitely ranks up there. I always love seeing work that isn't a bunch of off the shelf parts thrown at a car. That's not interesting to me. I like to see one-off, never been done kind of stuff. Keep up the work!

 

[Bob Kazamakis]

Can't believe I missed this! My mom had an 83 Grand Prix brougham in blue. My dad actually still has it tucked away. It's got some rust and that turd ass v6

 

[bs009]

Thanks guys! The motivation is very helpful!

It always amazes me to think that in 1982 the buick v6 was an absolute dog in these cars, then after they switched to fuel injection they had about 50% more horsepower. I can't imagine having to deal with one these cars and its factory carbureted V6 putting out a maximum of 110 horsepower if it were running optimally.

 

[bs009]

So I got the transmission squared away today. Swapping over the tail-housing was actually pretty easy with all things considered.
The donor transmission was a little hard to shift; turns out it had some water in it so I had to clean up all of the corrosion. Now that that's done and everything's lubed up it shifts pretty nicely.

And the Camaro transmission with the S10 tail-housing installed:

The only thing I have to worry about with it now is getting the right connector for the S10 speed sensor and figuring out which short throw shifter I'll use.

Next steps are getting the frame and body ready for the POR-15 treatment. That means cleaning up the body and dropping the fuel tank.
Also going to work out my motor mount situation this weekend and hopefully reunite the body and the frame!

 

[bs009]

A couple big updates here.

I spent basically all of last week getting the frame and the body together. I learned that the kit left out a couple of details so that made the experience a lot of fun.

This issue basically sums up what I learned last week.



so these need to ground down until they're flush; the body rests on these and leaves it too high to bolt to the frame.
Also, that piece needs to go on after the frame is bolted to the body in order to get the lower bushing in. I learned this the hard way.

Out with the old tank. New tank is made for EFI

Painted underside of body with POR-15:

Body back on frame:

The clutch also came in!

Here are those lower control arm braces I made before I put the frame back under the car:

Here are my home made engine mounts:

transmission cross-member replacement bushings. Basically made these from a strip of rubber and some extra steel from the frame kit.

the rubber:

and installed:

Here's how I handled the issue of the holes for the transmission cross-member:

bolts go all the way from the bottom. I used bolts that were 100mm long but 90 or 95 might work better; these were a tad long.

New fuel sending unit complete with a feed return and emission line :banana:
Just needs a sock and to be soldered properly.

And finally the engine and transmission where they belong!

with so much room for activities!

]

exhaust clearance might be low on this side:




shifter clearance in tunnel:




So there you have it. One more milestone completed. If this is done in time for the Michigan meet I'll be amazed.
Tomorrow I'll mark some holes for the shifter and figure out what I'll do for the transmission mount. Then I'll pull the engine and transmission back out so I can finalize the motor mounts. After that I'll move to cutting holes for the shifter and figuring out how I'll get a 3rd pedal in there.

After that I'll start working on the exhaust and getting the turbo mounted and everything. This week should be far less annoying than last week.

 

[bs009]

So it's been a while since I've posted. I had to take a bit of a hiatus from working on this since I moved away for work.
I recently started working from home though and was able to move back to Michigan. I've been crazy busy since I moved back, but I've still found some time to work on this. I'm back into it now and am hoping to have this thing running in next month or so.


So I ditched the S10 tailhousing on the transmission. it moved the shifter too far forward to the dash for comfort and also needed some work to fix some of the bolt holes that I didn't want to mess with.


I also did some more modification to the motor mounts to help place the drivetrain about 1/2" forward. I'm pretty happy with the placement now because it gives more clearance between the firewall and puts the transmission in a better location.

Spec stage 3+ clutch installed:

So here it installed again for what should be the last time in this iteration of the build:

While the intake manifold was off, I also replaced the lifters with LS7 lifters because I believe the original ones were ticking. Fearing having to pull it apart again because of something so silly, I just replaced them. I'll also have to replace the push rods and clean up the rockers because the two are pretty scored. Because of this I won't be able to finish the motor until I get new push rods.

I also started assembling the intake, but the GM upper intake manifold didn't come with the O-rings for the coolant port and the temperature sensor.....

So I just decided to mock everything up anyway though without bolting in the valve covers or the upper intake.

with plenty of clearance:

The transmission is also bolted up and the driveshaft is installed. I was able to use a factory transmission mount without having to modify it since I'm using the Camaro tailhousing again. I'm also pretty happy with the amount extra room between the driveshaft and transmission. I am using a 1" shorter driveshafte from the original build btw.

I'm anticipating replace the driveshaft with a 4" diameter shaft next year when I replace the axle and maybe the transmission also. Between now and then I'll have to decide whether to go with a t56 or a TKO600 as a replacement, but I'll cross that bridge when I come to it.



I also got a start on working the fuel lines. This car is now using all nylon lines to prevent fuel line corrosion in the future. So I get to work on attaching barbed quick-disconnects to nylon for the first time. These were a bit of a PITA, but I was pretty successful with these so far though:

Fuel lines in engine bay through frame:

Wix filter made for something? idk been too long

and the new fuel tank. This is an EFI unit made for a TBI Monte Carlo with my Walbro 255lph pump inside. I'll have to find a source for the wiring harness for the sender though. I haven't found anything yet so I may need to just cut and splice in a generic weatherpack harness..

Next up, hopefully engine final re-assembly, header build, and clutch pedal work.
One weekend at a time.

 

[10sec]

Really?!?! This is awesome. I love threads like this. I kind of started one of my own, but this is my favorite style thread, I can't wait for more updates.