BUILD THREAD 1978 Cutlass LS swap daily driver

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1970camaroRS

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Jul 17, 2014
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I started this more than a year ago, but haven't joined a g-body specific website. Thought I would join here and share it with you all.

Begin copy+paste.

I got laid off from my job in November and decided I would return to school to finish my degree. I suddenly found myself with a lot of free time while I waited for school to start, and not a lot of money. I had a 1966 Thunderbird sitting in the driveway in need of serious attention, a 1963 MGB roadster in the garage waiting for a back-half and V8 swap and said V8 sitting on an engine stand in the corner. I sold the cars and my professional camera equipment and went shopping for a car that I could quickly, easily and afford-ably get my LQ4 into. The catch was that it needed to be ready for long-distance road work and have room in the back to easily put my two kiddos, a 4 year old and a new-born. I found a '78 Cutlass that ran and drove but in need of some attention. It was very clean inside and under-hood, but is a few different shades of gray and silver and red and black. Owner was in need of money for dental work. I put $1200 in his hand and drove it 90 miles home. I drove it all summer without issue, then pulled the motor and trans out and sold it for $400. So I got the car for $800. I've been a busy boy since then.

I smoothed and painted the stock LQ4 truck intake. I cut everything down with a sawzall, attacked it with a dremel, used a plastic glue made for nylon 66 plastic to glue plugs in using a black spatula as donor material, used glaze and spot putty and sanded. More glaze and spot putty and sanded. Repeat. Repeat. Rinse, prime and paint. Used a Rustoleum metalic "satin nickel" paint.
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I had this bulkhead connector from US autowire sitting around and I'm using it for the guage wires, fuel pump relay and fan relay wires. Really nice piece! The stand-alone harness is from PSI Conversions.
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The radiator plate is an aluminum piece that allows me to ditch the stock mechanical fan shroud and use the stock Olds radiator. I'm using a one-speed mk-VIII fan that I've used on three different cars now. Best bang for your buck ever. I had to make a delete panel for the heater/ac. It fell apart on me and the firewall was riddled with rust. It's a simple sheet cut to shape, sealed and screwed. The headers are Pacesetters for an f-body I picked up for next to nothing and cleaned and painted. Intake tubing is from intakehoses.com. Upper radiator hose is for a 2002 Silverado and a Jags That Run splice fitting is used for the steam lines.
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Radiator deflector is aluminum and a really nice piece. I will probably build a box around the air filter to help keep it dry, but maybe not. I will have to see once the fiberglass bumpers show up. Hayden trans cooler.
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Tubular trans cross-member and drive-shaft safety loop.
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GN 8.5" posi rear with 3.42 gears. Summit diff-cover. QA1 sway-bar. New stock moog springs, Monroe Sensa-trac shocks, poly bushings on stock control arms. That's a new Dorman brand gas tank for a '86 GN with a sending unit from Racetronix with a Walbro 255 pump and AN -8 and -6 fittings.
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Used pro-stick shifter I'm integrating into the center console (not shown). The tach I had from my Camaro. Steering wheel came with the car. I picked up the 3rd Gen Camaro seats for $20, shampooed them and bolted them in. The guages are custom units from Speedhut and worth every penny I spent on them!
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The engine is a 2002 LQ4 with a mild Howards Cam suitable for a turbo, arp headstuds, MLS gaskets, ARP rodbolts, SLP double roller and ported oil-bump, LH8 oilpan drilled and tapped for a turbo oil-drain, stock 317 heads, truck intake. Trans is a 2004 4L80e with a Circle D 3,000 stall. Car should be fun. But I have run out of money and it might be a while before I can get a driveshaft made for it.
 
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And some pictures!

Nose sits a little high. I don't want to lower the car much so that I keep the ground clearance and comfy ride, so I might grab a pair of V6 springs for the front or a set of Eibachs since they don't actually lower the car much.
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The bumpers are in the mail!
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Side-exit exhaust actually worked out better than I thought it would as far as ground clearance goes.
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Took the top off, not too bad underneath. Rear window trim is in the mail!
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The other side of the roof where the lower trim was in the C-pillar is pretty rough.
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Not sure I can just weld this up....but that's what bondo is for, right?
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Pretty clean, eh?
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The office.
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GPS speedo and quad guages (volt, oil PSI, water temp, fuel).
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Wide-band, check-engine light and CD player.
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Small detail, the custom 442 shifter knob on my pro-stick.
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Videos!
 
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Got the new bumpers installed. A little bit of adjustment will be needed here and there, but they fit pretty darn good out of the box.
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For reference, this is what a 1978 Cutlass typically looks like:
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Much better with the integrated air-dam, I think. They're narrow and flush mount now too. I might paint the "bumper" portion a silver/gray, and the rest flat black with the rest of the car.
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Makes the nose look like it's not so high anymore. But with all that weight off the nose and the small front wheels, it looks a bit high with all of that fender-gap.
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Rear bumper is also now flush mount and narrowed. It was stupid-easy to install.
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What the rear bumper normally looks like:
oldsmobile-cutlass-1978-picture.jpg


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Not the cheapest thing I've put on the car, but well worth the money in my opinion.
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Close-up of the nose.
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Long time, no update. So here ya go.

Car is painted now. Rustoleum Charcoal Metallic spray paint. Lots of runs, flaws a plenty. Don't worry about door dings.

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Replaced the sealed beam headlights with Rampage buckets for H4 bulbs. I went with some nice UltraBright 4000K bulbs.

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The parking lights make them look yellow, but they're very, very white.
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While tuning I noticed my MAP sensor would drop to 92-94 KPA at WOT when ambient is 100 KPA. Then last week, the MAF failed. THEN the lower part of my intake tube fell off because the bracket weld failed and then I ran it over. So, I ordered up some 4" aluminum tube, 45 and 90 degree elbows to replace the 3.5" stuff I had before. I also threw the MAF in the trashcan. My old setup used a bit of a small filter, so this time I measured carefully and managed to fit a MUCH larger filter. IAT today was 66 degrees and ambient was 68, so the location works. Spare me the "you're gonna hydrolock it" comments please.

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Now I'm running a open-loop SD tune and I love it. Idle and low throttle acceleration is rock solid 14.68afr, low-load cruise is 16.4afr, and WOT is 12.8 to 13...however, my injectors are over 100% duty cycle, so WOT AFR isn't consistent. MAP reads 98-100 now at WOT, so the bigger filter, 4" tube and MAF delete is working. It's a difference I can really feel!

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Pictures of new tips installed. Still have to clean up the welds, but they're installed.
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And a video of start/idle/rev from driver's seat, then a walk-around and a rev from outside.
 
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New updates: Just passed 3,000 miles driven the other day. Still my daily driver.

Life is going better, my wife is back to work and I've hit my stride with my school program. Along with cutting huge costs out of my life, I've got a bit of money to spend...but not much! So, I got a hell of a deal for a FAST LSXrt intake manifold price matched by summit at $848 shipped! Also, a set of used 42lb marine injectors for next to nothing. I also ordered a custom cam from Martin at Tick Performance. 231/235 .635/.610 112+2. Should work better than the Howards 226/232 cam on a 115LSA and SLP 1.85 rocker combo. After selling my current cam, the SLP rockers and going back to my stock rockers, I should actually end up money ahead on this.

Then all I have left is to do front and rear coil-overs.

This is all because I'm committed to take it on the Northwest Drag Weekend this summer. More on that later.

I just hope this doesn't make me run quicker than 11.50 because I'm not sure I want to put a cage in the car since I drive my kids in it at least 3 days a week.

Oh, and my smoothed truck intake will be touched up and available for purchase!
 
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Had a spring break project with the car snowball just a bit. I had a hiccup getting the 42lb marine injectors and stock fuel rail to work with the LSXrt and 102mm throttle-body. Ended up ordering a Holley fuel pressure regulator, fast rails and FIC 42lb injectors. Got it all back together and.... only 30psi fuel pressure! Put 6 gallons in the tank. No change. Cranked the FPR adjustment all the way down. No change. It will fire up and idle for a while, but eventually the fuel pressure will bleed down and it dies. No leaks to be found anywhere. If I so much as breath on the throttle it stutters and dies. All roads point to a bad fuel pump, so a new one from Racetronix is on the way. I really hate dropping the tank...

Anyway, things look nice under the hood.
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Can't wait to get it all straightened out.

Also, while I was waiting for parts and what-not...I decided to get the suspension done. UMI tubular lower and adjustable upper control arms in the rear. BMR lower-control arm relocation bracket. QA1 anti-hop relocation on top (not a fan of this, will probably go back to normal poly bushing in the stock location). UMI drag race sway bar. QA1 14-130 coil-over springs in the stock spring location. QA1 single-adjustable shocks in the front and rear. Speedway tubular upper control arms in front and Moog 5658 springs. Brought the nose down about an inch so far. Also removed the front sway bar and set it aside. I'll re-install it if the handling gets too spooky.

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And of course, while I had the front apart I found out the both brake calipers were rusty and leaking, the pads were almost down to the rivets and one of the hoses was cracked. So I did a complete brake refit and did the wheel bearings while I was at it.
 
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New Racetronix pump is in the tank. I figured if I was going to go through the trouble of replacing the pump, I would get an upgrade. So, I went with their 340L/hr RXP pump. Fit right in the hanger no problem.

Car now has 58psi from the new pump. Neat bit of info I missed at first: the Racetronix RXP pump has an opposite polarity than the Walbro pump. I had to drop the tank again to swap out wires in the plug end. Oh, and don't forget to tighten up the outlet line to the sender in the tank. Had to drop the tank again to fix that mistake... Fires up and idles nicely now. Off to finish tuning!
 
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Tuning this thing has been a MAJOR pain in the *ss. Still have a bit of a cruise-control effect at 35mph, but the car fires up, idles and doesn't die when coming to a stop anymore. And it accelerates really, really well now.

30mph to 103mph in 6.8 seconds spinning hard for 1.2 seconds at 60mph per yesterday's log. Take away the tire spin and it almost matches acceleration with a 2015 Z06 to 100. But the car is doing 5,500rpm in 3rd at that point and will run out of gear shortly after 120.

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