1978 Porsche 911sc coupe 5.3 ls build
10-09-2013, 03:55 PM
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1978 Porsche 911sc coupe 5.3 ls build I have done several of these cars over the years, and have decided to start documenting some of the builds. see my 964 build as well here on the board.
this car is a 1978 911 sc coupe. very lightweight car/2200-2300 lbs with a 5 speed. a cheap boneyard 5.3 with mild mods will make this a rocket.
post script; mods to motor, ls1 intake, 78mm throttle body, ls2 cam and springs, otherwise stock lm7 5.3
this car is a 1978 911 sc coupe. very lightweight car/2200-2300 lbs with a 5 speed. a cheap boneyard 5.3 with mild mods will make this a rocket.
post script; mods to motor, ls1 intake, 78mm throttle body, ls2 cam and springs, otherwise stock lm7 5.3
Last edited by cobalt964; 11-08-2013 at 04:50 PM. Reason: post script
10-09-2013, 04:02 PM
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for those of you who don't know... and many don't... the Porsche 911sc is smaller than a vintage vw bug wheelbase wise. so sticking a 5.3 in one is like insanity. sure you could put a ls7 or ls9 in one but why? you can only transmit so much power to the ground before energy loss/wheel spin. you can only go soo fast til the gears run out/top end, so a 5.3 is perfect.
I am purposely putting in a boneyard 5.3 to do a budget build. yes I have new ls7, ls3, ls2, crate motors in the shop but I want to prove a point to some of my Porsche buddies. the car itself will stay entirely stock except for the ls install. stock brakes, stock suspension, stock trans, stock clutch. again, to prove a point. so here we go...
I am purposely putting in a boneyard 5.3 to do a budget build. yes I have new ls7, ls3, ls2, crate motors in the shop but I want to prove a point to some of my Porsche buddies. the car itself will stay entirely stock except for the ls install. stock brakes, stock suspension, stock trans, stock clutch. again, to prove a point. so here we go...
10-09-2013, 04:05 PM
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my custom built Porsche to lsx cradle I build allows usage of the truck ac and bracket, truck alternator with my billet alt mount, and usage of truck exhaust manifolds.
10-09-2013, 04:06 PM
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motor we are starting with. it is a 2003 lm7, will use a used l33 cam, ls1 intake rails and injectors, 78mm tb and maf. dual ss magnaflows. should make a conservative 350chp, which in a 2200-2300lb car will be a rocket hp to weight ratio wise. furthermore the stock brakes, stock suspension, and stock trans/clutch will take 350hp 350tq all day long reliably.
edit; ls2 cam and springs now
edit; ls2 cam and springs now
Last edited by cobalt964; 02-03-2014 at 02:20 AM.
10-09-2013, 04:12 PM
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again the Porsche motor is heavy and large compared to the lightweight and relatively small ls motors. even tho this is and iron block 5.3 it still is 30lbs lighter than the Porsche motor. crazy huh...lol.
10-09-2013, 04:19 PM
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again, like my other 911 builds, I use a plethora of top end meziere coolant parts, an fittings, stainless braided hoses, and a griffin nascar radiator with spal fans. aluminum fuel cell, so on. yes this is a budget build but the cooling system is not where you want to skimp on a build like this. remember I said I wanted a reliable car. lol.
the boneyard 5.3 cost me $850.00 and it only has 65k miles on it. came with starter, alt, power steering, ac bracket but no compressor, came with most of the harness, the ecm, both exhaust manifolds including the extensions with the o2's. a lot of the gm stuff I wont need, such as power steering, starter, flexplate, so on. so sell those parts or give them to a friend to help the build.
the boneyard 5.3 cost me $850.00 and it only has 65k miles on it. came with starter, alt, power steering, ac bracket but no compressor, came with most of the harness, the ecm, both exhaust manifolds including the extensions with the o2's. a lot of the gm stuff I wont need, such as power steering, starter, flexplate, so on. so sell those parts or give them to a friend to help the build.
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10-11-2013, 06:23 PM
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thanks jerrad. it just makes better sense to me. a used Porsche motor is 5-8grand. a rebuilt Porsche motor is 15-20grand. so a ls based engine is the way to go in my book.
10-13-2013, 08:55 AM
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Without a doubt man. If I had the skills and the space I'd be all over a project like this. Are you in OK? I'm from the NE corner near Tulsa, I'd love to come see it when I visit my folks.
10-14-2013, 05:39 AM
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Keep the pics coming! Let us know how you solved all the Porsche details with PS, WP, A/C, PCM, engine mounts, basically everything aside from the raw LS powerplant. Inquiring minds want to know….so does my Box, she wants to run!
10-14-2013, 09:39 PM
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I could do a boxster if I had it here for 30-90 days, depending on how far you want me to go. but other than that rh is the only ones with a "BOLT IN" kit for a boxster.
10-14-2013, 10:16 PM
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5.3 is mounted in the car. gonna try to leave the intake in the correct gm configuration on this one and possibly leave the truck intake on it. we will see how it fits.