LS Engine Swap in Seville

[hjlint]

You can check for leaky injectors with a fuel pressure gauge.  Connect to the rail, turn on the key,
the pumps will run briefly and shut off.  Pressure should go to 39 psi and hold for some seconds if
nothing is leaking. 

There is no doubt, driving style hugely influences mileage.  If the engine never gets
warmed up on short runs, it will be terrible.  Stepping on the brake is throwing away
gasoline; learn to minimize use of the brake.  Hills will cost more fuel.  I drive cars as
heavy and more powerful than yours, I drive fast and far, and mileage is always in
the upper teens (rarely reaching 20). 

The main difference between a 49 state ECU and a 79 CA is the OX sensor.  A 49 state
78-79 ECU will run your car just fine.  Of those I have tested, the OX sensor circuit usually
didn't work.  No parts available to fix the 8748 micro.  However, I can fix the rest. 

I wonder if they REALLY properly tested it; I haven't found anyone who could do that
except me these days.  I have started a list of COs that have said a bad ECU is good. 

Bruce Roe  CLC # 14630

Bruce, I can send you the all states PCMto see if it is usable. If so send me an addresst hjint@comcast.net

[gb2525]

Hi, I'm new to this forum so please bear with me. I am the guy that Gene Beaird referred to that did an Ls1 conversion into a 76 Seville. It's not that difficult. I started with a takeout package from a 2001 Z28 and used the Engine, 4L60, ECM, converted the stock wiring harness, Alternator, but not the AC compressor because I wanted all the accessories on top. I purchased AC and Alt. mounting brackets from KWIK Performance. MUCH less expensive than the BLINGY chrome stuff and they are laser cut Aluminum and very good quality. I'll correct a couple of  other items that Gene commented on. I used headers tailored for a Nova LS conversion. The crossmember I used was for an XBody LS conversion but the Seville frame is wider so I welded extensions on either side and drilled holes accordingly. Standard GM motor mounts on adapter plates available at several locations, EBay among others are from 50 to 100 bucks...get the ones that are drilled to allow for an inch of front to back adjustment. I I pushed the engine to the rear as far as I could but you don't have to. Oil pan I used is Holley 302-1 and provides plenty of crossmember clearance. Used stock diff with 3:42 gears as was stock in the Z28 and bought a Denny's aluminum driveshaft. Used the stock gas tank with a new  Walbro pump and used a corvette filter regulator setup. Works fine. Speedhut gauges in a custom housing, converted gas gauge to a Dakota digital display of tranny gear, GPS speedo is the way to go! I get around 18MPG mixed mode and around 25 on the highway. Have put nearly 10K miles on this combo. Sure I missed something. Ask away. Just purchased a 79 Seville with an L376 525 HP crate motor /4L 70 setup. So I'm not the only crazy one out there. The previous owner had between 36 and 40K in his conversion not counting whatever he paid for a low mileage one owner California car. I have less than A third of that in mine counting the cost of the car. This is my second conversion ( the other is a LS6/T56in a 67 Impala SS)
GBartlett

[Gene Beaird]

Hey, Gary!  I'll note that Gary's swap is everything one would want in an engine swap. It works, AND looks factory. When I see the car, it's all I can do to fight the urge to do one myself. It's that good.

The car he picked up recently sounds like yet another winner. I'm, so far, happy with our 79. We have many more projects to work on.