« Reply #2 on: April 07, 2013, 01:59:46 AM »
My 1980 Green SW has a Howell kit on it right now. It starts up and idles perfectly with minimum complexity, it's pretty slick. I would love it if they didn't charge you three times their cost. Make sure you ditch their fuel pump and install a factory GM version inside your gas tank. It's noisy and unreliable and crazy expensive to use their pump.
Also be prepared to have trouble with your return vapor lines. With the Howell kit those need to be in perfect shape because they will now carry a steady volume of gasoline back to the tank from the fuel pressure regulator. It is a much heavier use than they ever had originally. Mine was clogged and restrictive, and it caused the pressure to spike way too high. That leads to terrible hissing, pathetic idle, and horrible gas mileage.
Your 1980 probably has the cast intake and exhaust manifold. Try to ditch that for a 1981 up style intake and exhaust manifold like I did. Get all the linkages and cables all the way to the gas pedal itself if you do.
Yes a 4.0 head will bolt on to your engine if you read the directions. Fill in the water jackets. Make a pair of alignment dowels from an old pair of 4.0 head bolt upside down with the hex head ground off. Realize that minor modifications to your brackets will be necessary to account for a slight shift in your intake location.
I think you made a mistake describing your valve cover woes. There are three types. 1980 has steel. 1981 to early 1987 has plastic that can be replaced by the common aluminum aftermarket covers. I think that's what you meant when you said you bought one already. Late 1987 is aluminum exactly like the early 4.0 covers and is interchangeable with the newer 4.0 covers readily available in junkyards.
In other words I don't think you'll be able to use the 4.2 valve cover you purchased with either your 1980 head or a 4.0 head.
Logged
Currently Inspected and Insured as of Jan 2013:
-1985 Eagle Station Wagon 258 T5 Stickshift
-1980 Eagle Station Wagon 258 Auto Fuel-injected with GM TBI
Minor Repairs Underway:
-1982 Eagle SX4 258 T5
-1981 Kammback 2.5L Iron Duke T5
Restoration Efforts Near Completion:
-1982 SX4- 401 NV3550
-1983 SX4- 4.5 MPI NSG370 (6 Speed)
Restoration Efforts Underway:
-1985 SW- 4.0 MPI AX15
-1982 SX4- 4.0 AW4
-1981 SX4- SD33T NV4500 (Turbodiesel 5 speed)
Future Rescue Efforts- '85 Maroon SW, '87 Limited SW, '84 Limited SW, '87 4 door Sedan, '81 2 door Sedan, '88 White SW, '77 4 door Hornet, '74 2 door Hornet, '79 Spirit AMX, '81 Kammback.
RIP- Red '81 SX4, '84 4dr Sedan, '84 SW, '81 SW, '80 Spirit, '83 SW, '83 4dr Sedan
Topic: 1980 Cedan Head Swap (Read 3818 times)