Results 1 to 3 of 3

motor install

This is a discussion on motor install within the GM Trucks forums, part of the Vehicle Specific category; i bought a 2003 gmc sierra regular cab fleetside today,with a 4.3 liter v6 and an automatic,i was waondering if ...

  1. #1
    Junior Member sammy1979's Avatar
    Join Date
    Aug 2006

    03 silverado

    motor install

    i bought a 2003 gmc sierra regular cab fleetside today,with a 4.3 liter v6 and an automatic,i was waondering if anyone has swapped an ls1 into one yet and if you have what is the entire list of everything needed to drop it in and start driving it

  2. #2
    Junior Member
    Join Date
    Aug 2005
    Ft. Lauderdale, Fl.

    '96 C-1500

    LS1 Swap...

    I recently completed an LS1/4L60E swap into a GMC fleetside that an LS series engine was never an option in. It's a '96. It was a bit of work, but holy cow, was it worth it! This thing gets it! I have heard, because of the extensive research I have done, that an LS1 swap into your 2003, is a piece of cake. Thats because the LS series V-8's were an option in all the new body style trucks, meaning 1999 to present. The aluminum LS1 5.7 is the same exact size as the cast iron counterpart that was a factory option in your truck. The first question is always...where do I buy the motor mounts for my swap? Answer(in your case): the local GM Dealer, or a bone yard. Any of the '99 & up V-8 motor mounts will work on your swap. Your existing 4L60E tranny will bolt up also. I have heard that a small flywheel spacer is all thats required. Check over on LS1Tech, in the Conversions & Hybrids section, and do a search. Or, it should be right at the top of that sections page. Hope this gets you going! Gar

  3. #3
    Junior Member RandyW's Avatar
    Join Date
    Aug 2005
    Salisbury, MD
    I have an '02 short bed/ reg cab/2wd that was a 4.8 originally. Last winter we installed an LS1, using the truck intake and injectors and still has stock programming, WOW! The difference is phenominal! The only none stock item other than the LS1 is the exhaust, it has a Magnaflow single outlet system. The engine was so much lighter that the front came up about 3/4". I love it!

Thread Information

Users Browsing this Thread

There are currently 1 users browsing this thread. (0 members and 1 guests)


Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts