Author Topic: LS376/515 swap in a '78 Trans Am  (Read 224 times)

skisix38off

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LS376/515 swap in a '78 Trans Am
« on: November 28, 2018, 08:08:48 AM »
I've started my journey into the LS swap area.  My Poncho 400 is made of good parts and has done a great job of taking me this far, now it's time to get some good power to the ground and to make the car more reliable.  I bought a GM Performance Crate LS376/515 - this is an LS3 with the LSA Racing cam in it bringing it to a rated power of 533hp and 486tq.  It has 871 heads and the Victor Jr intake manifold as opposed to the typical MFI black plastic intake.  I want this to work with my shaker and while I could develop a way to mount my shaker with the plastic intake, I just want to keep my shaker functional without fab'ing something up.  I will also be using a Holley Terminator LS system to control the ignition and provide Fuel Injection.  I am looking forward to all the benefits of FI on this car and to have the computer make the adjustments to keeping it running well and me not having to guess at which secondary rods to use and all the other stuff associated with maintaining a premium tune. 

I have bought a new LS conversion radiator to keep it cool and will use 4th gen dual electric fans controlled by the Terminator system.  I went to BRPHotrods.com to get the engine mounts and trans crossmember for the T56.  The T56 is going to be rebuilt to handle the new power/torque.  And I also purchased a AutoWire harness to go to the terminator system and to feed the Dakota Digital gages.  I bought a new fuel tank with in tank pump to supply fuel. 

At this time I will use the supplied exhaust manifolds and fab a mid-pipe to go from there to the current exhaust.  As part of this change over I will also go to a 4 link in the rear to handle the new power- those leaf springs don't stand a chance!

The new crate engine arrives!




I think that Victor Jr intake looks great!


Out of the crate and onto a stand.  I have to do this step because the LS376 comes with an oil that doesn't work for 2nd gen F-bodies, and I am installing an Improved racing oil pan baffle to help ensure that the engine is always supplied with oil.


Now for the Current set up...












Soon, the transformation will take place.  I am hoping to have it driving again in early Feb., 2019.

Pit crew and security crew! 



Steve B

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Re: LS376/515 swap in a '78 Trans Am
« Reply #1 on: November 28, 2018, 08:16:29 AM »
Good luck with the swap.  I think the dogs might need to be put to work to help out. :lol:
Steve
1980 Trans Am, 400, TH400 auto

ryeguy2006a

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Re: LS376/515 swap in a '78 Trans Am
« Reply #2 on: November 30, 2018, 01:41:34 PM »
Looking great! you won't be disappointed with the LS motors. My dad just picked up a Terminator kit recently and we're looking forward to installing it on his 1971 Chevelle with a 496 BBC. Keep us posted!

1976 Trans Am LS1, 6 speed, C5 12.8" Brakes, LS1 rear 12" brakes, 17" Aluminum Rims, and much more...SOLD
My Build: http://transamcountry.com/community/index.php?topic=24465.0

New project: 1968 Camaro with 6?.?0?  5.3 w/ Z06 cam/T56
http://transamcountry.com/community/index.php?topic=74591.0

skisix38off

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Re: LS376/515 swap in a '78 Trans Am
« Reply #3 on: December 03, 2018, 07:57:37 AM »
I had to do a few little custom touches this weekend. 







I also received and installed my Improved racing Oil Pan Baffle to help keep the oil pick up covered in oil even on high G corners.  This is a nice piece. I also got my 4TH Gen Oil pan to install it in. 


1979 Black and Tan

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Re: LS376/515 swap in a '78 Trans Am
« Reply #4 on: December 03, 2018, 01:06:02 PM »
very nice..is there a reason you went with a carburetor and not with the fuel injection that usually comes with these GM engine packages?

like this one

https://www.chevrolet.com/performance/crate-engines/dr525-muscle-car-oil-pan
1979 Trans Am
100% California Car, originally Atlantis Blue/ Black...All Original Unmolested 403, TH350, 2.41
63,300 orig. miles
1971 Chevy K20 4x4

Re: LS376/515 swap in a '78 Trans Am
« Reply #4 on: December 03, 2018, 01:06:02 PM »

skisix38off

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Re: LS376/515 swap in a '78 Trans Am
« Reply #5 on: December 04, 2018, 07:39:07 AM »
More goodies arrived!











skisix38off

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Re: LS376/515 swap in a '78 Trans Am
« Reply #6 on: December 04, 2018, 07:49:23 AM »
very nice..is there a reason you went with a carburetor and not with the fuel injection that usually comes with these GM engine packages?

like this one

https://www.chevrolet.com/performance/crate-engines/dr525-muscle-car-oil-pan

I was originally going to buy the engine you linked above.  There are several factors involved in my case, cost and availability, and it's very important to continue using my shaker.  The more I get into this though, I am so glad that I made the decision I did.  See below...











I do have fuel injection!  I will have all the conveniences of FI and all the performance advantages of FI.  And this system allows a DIY'er like me install anLS engine just like it was any Pontiac engine and this route is $2000 cheaper.  The Terminator LS system will also allow me to go to Multi-Port in the future if that's what I want.  Most of all, I believe the air cleaner, thus shaker, will fit right on top!  Then, there's the cool factor when the hood is up.

ryeguy2006a

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Re: LS376/515 swap in a '78 Trans Am
« Reply #7 on: December 04, 2018, 09:39:26 AM »
Great choice! I will be helping my dad install his Terminator EFI this winter too. Hopefully tearing up the streets this spring! Keep us posted on your progress.

1976 Trans Am LS1, 6 speed, C5 12.8" Brakes, LS1 rear 12" brakes, 17" Aluminum Rims, and much more...SOLD
My Build: http://transamcountry.com/community/index.php?topic=24465.0

New project: 1968 Camaro with 6?.?0?  5.3 w/ Z06 cam/T56
http://transamcountry.com/community/index.php?topic=74591.0

jonathonar89

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Re: LS376/515 swap in a '78 Trans Am
« Reply #8 on: December 04, 2018, 11:05:47 AM »
Exactly how I think shaker T/A guys should be doing their LS swap right here.  950cfm 4 Barrel

Good stuff.
1979 Trans Am 400 T-top - Platinum Silver, Carmine Interior
http://transamcountry.com/community/index.php?topic=61460.0

1979 Black and Tan

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Re: LS376/515 swap in a '78 Trans Am
« Reply #9 on: December 04, 2018, 03:28:22 PM »
this looks amazing....
1979 Trans Am
100% California Car, originally Atlantis Blue/ Black...All Original Unmolested 403, TH350, 2.41
63,300 orig. miles
1971 Chevy K20 4x4

skisix38off

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Re: LS376/515 swap in a '78 Trans Am
« Reply #10 on: December 05, 2018, 07:39:17 AM »
Steam vents????  Can someone chime in on this?  This is a detail about LS that I have read as being very important, how does it get connected?  Part Numbers?

Updated71

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Re: LS376/515 swap in a '78 Trans Am
« Reply #11 on: December 05, 2018, 08:36:53 AM »
Mine is T-ed into the upper radiator hose similar to how it was done on some LS based GM trucks.  I haven't had any issue using this, but have not had an opportunity to do any type of competition such as your car sees.  I am using a transition from jagsthatrun.com.  https://jagsthatrun.com/collections/cooling-systems

I have a 17 SS and the line is attached at the top of the radiator just above the inlet for the upper radiator hose. 

If you decide to run an expansion tank, it may have a dedicated provision for this line.  C & R Racing tanks do.  Some find factory tanks at the junk yard and use them. 


The earlier LS motors had 4 ports all tied in together from both the rear and front.  I believe it was to prevent a particular piston or pistons from overheating.  At some point, only the front ports were open and required venting. 
The surgeon general never said nuthin' 'bout smokin' the competition!

skisix38off

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Re: LS376/515 swap in a '78 Trans Am
« Reply #12 on: December 05, 2018, 10:52:35 AM »
Do I have this correct?


jonathonar89

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Re: LS376/515 swap in a '78 Trans Am
« Reply #13 on: December 05, 2018, 11:09:36 AM »
1979 Trans Am 400 T-top - Platinum Silver, Carmine Interior
http://transamcountry.com/community/index.php?topic=61460.0

Updated71

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Re: LS376/515 swap in a '78 Trans Am
« Reply #14 on: December 05, 2018, 11:59:19 AM »
At the rear of your picture, the part that is just off center of the intake is the oil pressure sender.  The port on the drivers side valve cover is capped off on my 11 production engine (Corvette based) and on my 17 SS.   Some use these ports for catch cans/oil separator. 

The front PCV port can be tied in after the MAF to keep it cleaner from oil.
The surgeon general never said nuthin' 'bout smokin' the competition!

Re: LS376/515 swap in a '78 Trans Am
« Reply #14 on: December 05, 2018, 11:59:19 AM »



ryeguy2006a

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Re: LS376/515 swap in a '78 Trans Am
« Reply #15 on: December 07, 2018, 07:17:28 AM »
Yes, Updated71 is right the port on the rear of the valley cover is for oil pressure.

1976 Trans Am LS1, 6 speed, C5 12.8" Brakes, LS1 rear 12" brakes, 17" Aluminum Rims, and much more...SOLD
My Build: http://transamcountry.com/community/index.php?topic=24465.0

New project: 1968 Camaro with 6?.?0?  5.3 w/ Z06 cam/T56
http://transamcountry.com/community/index.php?topic=74591.0

Re: LS376/515 swap in a '78 Trans Am
« Reply #15 on: December 07, 2018, 07:17:28 AM »
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