Conversions & Swaps LSX Engines in Non-LSX Vehicles
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LS1 Conversion Complete 72 grand Prix

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Old Feb 8, 2008 | 02:55 PM
  #21  
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Very nice car.
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Old Feb 9, 2008 | 01:17 PM
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From: Little Austin
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Great swap! Any pictures of the bottom that shows the C5 oilpan fitment?

Andrew
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Old Feb 9, 2008 | 01:36 PM
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I'll post some next time I put it up on a rack. Thanks!
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Old Feb 9, 2008 | 03:19 PM
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any info on how/what was done to the stock tank to use it with the fuel injection?
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Old Feb 9, 2008 | 06:21 PM
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Bought a PA-4 pump kit from Tanks Inc. Uses a Walbro GSS340.

http://www.tanksinc.com/index.cfm/pa...prod/prd84.htm

Removed, cleaned, emptied, repainted the tank. Was gonna fill it with water before operating, but found I could not get all the gas out, therefore I figured I never get all the water out either. So, I prayed, then cut a 5" hole adjacent to the stock sending unit. Just drilled a few small holes, then used sheet metal cutters to get it to size. Cut the pump assemby to length and connected it to the stock fuel lines with AN6 fittings and braided hose. The seal ring is sorta hard to hold in place while putting in the screws. There's a ring that goes inside the tank for a backer. Stuck my fingers through the stock sending unit hole and the backer in place while fastening. Sealed the edge with RTV. Kept the stock sending unit to work my fuel gauge.

Used one of the vent lines (the tank has 3) for the return. Used AN6 fittings to connect to the fuel rail and used the EGR line for the return. The supply and EGR lines are 3/8". The stock return line was too small and they don't have AN tube fitting smaller that 5/16." Ran the wires through the passenger side frame rail. Pumps 60 PSI no matter what. The 98 Corvette engine has a 5/16" return at the fuel rail, so it was pretty easy. Had 100 PSI at first because I connected the return to wrong place at the tank. The Grand Prix has a manifold of inlets, return, and vents at the tank that was sorta hard to figure out. Capped off all unused lines.

Tightened the tank straps barely sung, so the pump assmbly would not be too tight against the trunk floor. Used the stock retun line for a vent . I have a vented locking cap and stuck a red hot ice pick into the nylon vent to make sure it was open.

Last edited by Frnichols; Feb 9, 2008 at 08:13 PM.
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Old Feb 10, 2008 | 01:21 PM
  #26  
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I used some mounting plates to the block, then drilled and tapped holes to relocate the stock corvette mounts. Welded some gussets to the back of the crossmember and used S&P bisquit mounts.
Attached Thumbnails LS1 Conversion Complete 72 grand Prix-dsc00154.jpg   LS1 Conversion Complete 72 grand Prix-dsc00155.jpg   LS1 Conversion Complete 72 grand Prix-dsc00157.jpg   LS1 Conversion Complete 72 grand Prix-dsc00158.jpg   LS1 Conversion Complete 72 grand Prix-dsc00160.jpg  

LS1 Conversion Complete 72 grand Prix-dsc00161.jpg   LS1 Conversion Complete 72 grand Prix-dsc00162.jpg   LS1 Conversion Complete 72 grand Prix-dsc00163.jpg   LS1 Conversion Complete 72 grand Prix-dsc00167.jpg   LS1 Conversion Complete 72 grand Prix-dsc00168.jpg  

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Old Feb 10, 2008 | 01:28 PM
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From: Little Austin
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Very nice. It's amazing how far back your engine sits. I never would have thought that the c5 oil pan would fit.

Andrew
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Old Feb 13, 2008 | 10:22 AM
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I think it's an illusion. The engine sits in the same place as it would in an A Body, but the crossmember is futher to the front and there's about 2 feet added to the front clip. From the firewall to the rear bumper, a G Body is the same as an A Body.
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Old Feb 13, 2008 | 11:09 AM
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From: Little Austin
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Originally Posted by Frnichols
I think it's an illusion. The engine sits in the same place as it would in an A Body, but the crossmember is futher to the front and there's about 2 feet added to the front clip. From the firewall to the rear bumper, a G Body is the same as an A Body.
I was actually judging by the position of the oilpan and the crank pulley. I know all about the 6 foot long Grand Prix hoods! LOL

You may want to think about moving the air filter down low. Picking up the hot air off the radiator is costing you power. LSx engines are fairly sensitive to air intake temps and the ECU will aggressively retard timing as temps go up.

Andrew
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Old Feb 15, 2008 | 06:34 PM
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Can you suggest a good cold air kit?
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Old Feb 15, 2008 | 06:43 PM
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Home Depot!! Ftw
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Old Feb 16, 2008 | 07:55 PM
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From: Little Austin
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Originally Posted by Frnichols
Can you suggest a good cold air kit?
You can get elbows and piping from any number of sources. I would just put a 90 degree elbow off the throttle body and go down. You can pick up cool air from under the car.

Andrew
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Old May 27, 2008 | 01:06 PM
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Originally Posted by Frnichols
New crate LS1 installed in my 72 Pontiac grand Prix. It's a 1998 Corvette LS1 service replacement crate motor. The Corvette oil pan fit without crossmember modifications. Just had to weld on a couple of gussets to the rear of the crossmember. Used adapter plates and the stock pedistal mounts. I thought the G body and A bidy were the same regarding the frame, but discovered otherwise. The G body frame crossmember to several inches forward. Have a 700R4 with a 2:37 12 Bolt LSD.
Clean swap, what did you use for a kickdown cable & bracket for the 700R4?
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