Mine looks the same w/ 3 nuts which secure it to studs on the IP. Yes, very difficult to swing a wrench. All I could get on was a thin 10 mm box wrench, but not ground down (like for the fan clutch). Problem is it is spring-loaded so you can't just loosen then spin the nuts off with your fingers. With the spring, you must slowly wrench them off little by little. Of course, if you get the crank in the right locating, the plunger will be more extended so the spring won't fight you as far.

Insure you have the correct gasket. I swapped an IP last year and got too jiggy because I didn't have the proper gasket. I thought a round one I had for another set would work, but it left the ears cantilevered. Later, my son complained of an oil leak and found one ear had snapped off. Fortunately, I had a spare lift pump, and had ordered the proper gasket in the interim.

Re alternate lift pumps, I saw many on ebay for Bosch IP's when searching for rebuild kits. They were much cheaper than for our cars. The bodies looked almost the same, but the orientation of the fuel ports varied, w/ many sticking out horizontally. Perhaps someone will figure how to adapt one to our cars.

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1984 & 1985 CA 300D's
1964 & 65 Mopar's - Valiant, Dart, Newport
1996 & 2002 Chrysler minivans