The term "lump" sounds like the results of encountering a pair of brass knuckles in a dark alley. But it actually refers to a Jaguar who's engine had been replaced with a Chevy V8. Jaguar purists hate the idea, but during the 1980's American dealerships were actually known for placing Corvette engines into new XJ6s. I must admit that it doesn't sound like the right thing to do, but after owning two Jaguars, I can appreciate the need. So did another Jaguar owner.
Early in 1994, I purchased a Jaguar XJ6 from a local seller. The car was complete, but there was water in the oil. It was the general opinion that the problem was a bad head gasket and/or head. It did not matter much to me - I purchased the car for next to nothing and fixing the head gasket would be a snap. I started to remove the head, and I discovered why Jaguar mechanics are such special people. I personally am comfortable working on any of the major USA car brands, since I have had my share of cars which needed fixing. The Jaguar 4.2 motor, however, was a learning experience. The thing that made me ponder the reason why the car was sold so inexpensively was when the cylinder head refused to budge loose because of corrosion in the head studs (it turns out that the studs penetrate the water jacket). I had to use a chain hoist hooked to the head, and winching the ENTIRE car up by the head and waiting for a day, the head to eventually slide off.There's a certain amount of sense in what he did. And with the cost of classic Jaguar repairs rising above $100 per hour, it makes even more sense.
I had heard from numerous sources that many people have removed the original Jaguar motors and transmissions, and put in Chevy or Ford powerplants. Why would anyone turn a Jag into a hybrid monstrosity? The reasons stated were "Parts are much more inexpensive for Chevy motors than Jaguars", "Better gas mileage", "I can drive anywhere in the USA and if I have car problems, I can have the thing fixed right there without waiting for parts to come in", "I am more familiar with Chevy engines than Jaguars", etc. I discovered that in the case of a Chevy swap, it is almost a "bolt-in" affair - one can perform a swap without any cutting or welding on the Jag body whatsoever. For instance, one can use a driveshaft from a '70's Nova and it is the correct length to go between a Turbo 350 and the Jag differential, and Jaguar uses the same U-joint as Chevy, so it bolts right up. The power steering lines also bolt right up. One can put in a Camaro radiator in place of the Jag unit, without any cutting.
So, after the research, I decided to put in a Chevy 350 and Turbo 700R4 overdrive automatic. The funny thing is when I posted what I was planning on doing, Ryan Border inquired on what I was going to do with the original 4.2 Jaguar motor. He purchased the motor, and I boxed it up (I live in Virginia) and proceeded to ship it to California. It now lives in Ryan's 1959 MK1. There is even a picture of the original motor before installation in Ryan's car. ... Even though not everyone agreed on the philosophy of the swap, everyone helped out with numerous technical questions. ... I have put over 20,000 miles on the converted car (June 1995), with absolutely NO problems associated with the swap.
"Chevy 350 in a Jaguar XJ6 - Hybrid Heaven" by Bruce Bowling