Old School meets New - Supercharged LSA/4L85E into Grand National


Feb 27, 2002
Hi All,
My newest project is a 1987 Buick Grand National with an CA emissions-legal GMPP Connect & Cruise E-Rod LSA kit stuffed into it:

I bought the car in July for the straight body & frame and it suffered a tranny blowout on the drive home (after a 1 hour test drive and 2 hours on the highway - I really don't think this guy had any idea it was going to blow).
Once I started looking at the ridiculous prices for the original, reasonably low-tech Buick tranny and motor parts, I started checking out alternatives.
I was going to stuff an LS3 in there then put a turbo on to keep the original theme going, but they're cracking down on the smog testing pretty hard and I really wanted the beefier 4L85E tranny to handle the power once I started to mod, so I decided to spring for the LSA.
I found Gandrud Chevrolet in WI and they are running a special through the end of the year - double the GM rebate of $750 back, and Pete threw in free shipping to my door. Total for the engine and tranny and all electronics/cats/pump/emissions stuff with the rebates was $16,300. Like $3300 better than I could do in CA.
So I just ordered all the drive accessories to place the PS and alternator up higher on the driver's side to clear my steering box, and the ZL1 lid as the plumbing will be cleaner for my application. I'm using the Hooker LS swap cast iron headers to start as I can carefully grind off the Hooker logo then blast them with steel shot, ceramic coat them and they will look factory, plus the angle of the exhaust clears the G-Body front suspension pickup points perfectly.
Lots of work ahead but it should be a cool project and once I start putting on some of the greats mods you guys are doing it should be a solid performer in a classic shell.
Big Delivery Yesterday!
The big crate on a pallet was a bitch to get off the truck, down the COBBLESTONE driveway (little wheels don't like to roll on it :() and next to the garage. Here's its future home, the tranny in the black tub and all the motor bits in the monster crate:

After a lot of prybar action:

Details start to emerge:

Here's the real surprise - the GM Parts Manager swore that this would come with a flexplate and that they had stopped shipping with a flywheel/clutch combo:

I'll probably sell the clutch and flywheel as I could use the money for other bits.
I ran out of time to get it up on the engine stand because I need to make sure I remove the clutch & flywheel correctly, so it's just hanging by one side until tomorrow:

Still waiting on all the front GM Accsy Drive stuff, the Mast oilpan, assorted other bits.
Here's the 14", six-piston front (on the right) and rear brakes that will eventually go on the car, after I decide on and order my 18" wheels:

First order of business - take off the heads and get them CNC-ported while the motor is out of the car. WCCH is going to breathe on these and install a Brian Tooley dual spring kit at the same time.
Second - get it in and get it smogged, to get the state off my back. Then the mods can continue.
Fun times ahead.
Got Shoehorn?
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That's exactly what I want! I was wanting to install an lsa with the concept one billet pulleys but not sure if would clear the ps pulley? Would like to see the clearances in that engine bay. Keep us updated in the install!

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Bitchin' build man! Your engine and tranny cost about as much as I paid for my GN, but I'm diggin' the direction of this project.

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Got the motor up onto the engine stand, and started in on the initial mods, which are the ones that will be pretty invisible and not affect passing CA smog.

Pulled the supercharger unit, which of course is not showing the lid here. This is easy as everything on top comes off with it - injectors, rail, sensors, etc. You just remove the cover then 12 bolt inside then lift it off. They even cast in a place for your hand to grab!


Cleaned out all the head bolt holes (they used something darn near stud & bearing mount for the head bolts - tough to remove and clean) and studded up with ARP:

The heads went off to West Coast Cylinder Heads for CNC porting, dual springs and titanium retainers. I also went to Inconel exhaust valves in case I ever put the Whipple 3.4 head unit on this motor (would probably need a cowl hood). The ARP head studs are stronger than stock and reusable.

Swapped on the MAST oil pan & pickup, which is the cleanest fit (and install - ever hit the bottom of your pan on the crossmember :wtf: ):

I am accumulating the parts I will put in after the smog: Brian Tooley Stage II cam (from Comp Cams), Dirty Dingo motor mounts, ZL1 supercharger cover, overdrive pulleys, bigger injectors for E85, flex fuel setup to handle anything from straight pump 91 to good E85, and any blend between.

The Racetronix dual in-tank pump is on the way. I am hooking up a Hobbs switch set at 4psi to turn on the 2nd pump. This pump will handle anything I can throw at it. I will plumb the fuel system with -8 Teflon hose with a -6 return.
My target is 630-650rwhp, which is VERY doable on E85. On pump 91 it will be around 580rwhp. But there's lots of E85 around here now 8)

10 years ago who would have thought this possible in California? The smog Nazis are spinning in their graves!


The only sticker I actually want on the car.

Two weeks for the head porting. Time to pull the turbo motor and clean the engine compartment, unh.

I must admit that I have mixed feelings about this. But I am SUBSCRIBED!
What are your predictions for the quarter mile? From what I've seen the ctsv is around 12.5 1/4mile and its weight is around 4200 from what I've seen in the past. I don't see why you shouldn't be around 10's?

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Very cool swap, it's a shame you live in such a commie state that you can't even pull off a turbo ls swap without angering CARB. Keep us updated.
Got the old GN motor out last night:


~28 years of grunge built up on a motor/chassis combo that's 50% metric, 50% standard and 10% random "other" bolt sizes & thread pitches from around the world. :rolleyes:

Now I can get in there (literally - you know what I'm talking about) to clean, remove bits I don't need and start sorting out the wiring that I will need after the motor swap, like AC/Heat controls, Starter/charging, etc.

The heads are on their way back from WCCH, probably will arrive tomorrow, so after that I can get the LSA back together enough to mark up the blower for some porting and head matching that I'll do next weekend. I may do some testfitting of the motor before that so I'll know if I have any issues like having to relocate the #8 and or #7 coils, or any mods to the AC heat shield.

If you are using the 1" setback mounts, #8 coil will be very tight. I have an ac delete plate on my firewall so mine clears fine, yours will be tough. #7 will clear fine.
Thanks. I am using the Dirty Dingo adjustable (slider) mounts so I may be able to set it so that it fits, especially if I remove the metal GN heat shield there. If I have to I will remove the AC but this was supposed to NOT be am all-out, no comfort street machine - I already have the Grey Ghost for that.

Test-fitting the modified front accessory dressout - this is a mix of LSA and LS7 parts, LSA on the left of the picture and the ALT & PS on the right is from an LS7. This gets the ALT & PS up higher to clear the G-Body steering box. I love getting a big box of OEM parts and watching it come together.

This also shows the ZL1 supercharger lid, which has the IC lines in the front (should be better for my install) and is reported to be worth about 20HP over the shorter LSA cover:


I still need to use a pulley installer to put on the PS pulley, then I can fit the belts. So far, all the parts have shown up correctly, have fit, and look like the pulleys are all aligned correctly. Fingers crossed!

WCCH did a nice job on the CNC porting of the heads:


Boatloads of work ahead. :peeking:

If you do have to remove the AC box, Nick Micale now has your under the dash AC solution available.