Jaguar XK120/140/150, The Complete Buying Guide

Overview

The Jaguar XK sports cars, the XK120, XK140, and XK150, are among the most beautiful and important cars ever made. Produced between 1948 and 1961, they established Jaguar as a maker of world-class sports cars and introduced the legendary XK twin-cam six-cylinder engine that would power Jaguars for the next four decades.

The XK120 (1948-1954) was the fastest production car in the world when launched. The XK140 (1954-1957) refined the formula with rack-and-pinion steering and more power. The XK150 (1957-1961) brought disc brakes, the option of the 3.8-litre engine, and the devastating “S” specification with triple carburettors and 265bhp.

These are serious collector cars with prices to match. But they’re also genuinely usable, a well-maintained XK is a spectacular long-distance touring car with performance that remains impressive today.

Which Model to Buy

XK120 (1948-1954)

The original and purest of the XK sports cars. The 3.4-litre XK engine produces 160bhp in standard form (180bhp in SE/Special Equipment tune). Early cars (1948-1950) had hand-formed aluminium bodies over an ash frame, these are rare and extremely valuable. From 1950, production switched to pressed steel bodies on a separate box-section chassis.

Three body styles: OTS (Open Two-Seater/Roadster), DHC (Drophead Coupe), and FHC (Fixed Head Coupe). The roadster is the most desirable and the most expensive. The FHC is arguably the most beautiful of the three and the most practical, it has a proper boot and wind-up windows.

Pros: The purest XK, the most valuable, stunning looks. Cons: No synchro on first gear (Moss gearbox), drum brakes, the most demanding to drive, the most expensive to buy.

XK140 (1954-1957)

The improved XK. The engine was moved three inches forward (improving cabin space), rack-and-pinion steering replaced the recirculating ball unit, and the SE tune became standard. Power is 190bhp standard, 210bhp with the C-type cylinder head option. An automatic gearbox option was added.

The XK140 is the sweet spot for many buyers, it’s noticeably easier to drive than the XK120, with better steering response and improved cabin room. It’s also less expensive than the XK120, particularly in DHC and FHC form.

Pros: Better steering, more power, more refined, better value than XK120. Cons: Still has the Moss gearbox (no first-gear synchro), still has drum brakes, slightly less pure in character.

XK150 (1957-1961)

The most refined and capable XK. Disc brakes on all four wheels (a first for a production car), a wider body with a one-piece curved windscreen, and the option of the 3.8-litre engine. Standard 3.4 produces 190bhp, the SE gets 210bhp, and the “S” specification with triple SU HD8 carburettors and a straight-port head produces 250bhp (3.4) or 265bhp (3.8).

The XK150S 3.8 is the ultimate road-going XK, 265bhp, disc brakes, and a top speed well over 130mph. It’s also the most expensive variant after the alloy-bodied XK120.

Pros: Disc brakes, most power, most refined, the S is devastatingly fast. Cons: Heavier, less pure in appearance (some prefer the earlier cars’ looks), the most expensive 150s rival XK120 prices.

Roadster vs DHC vs FHC

The roadster (OTS) is the most desirable body style across all three models and commands the highest prices. The DHC offers open-air motoring with the convenience of wind-up windows and a more substantial hood. The FHC is the most practical with a fixed roof, proper boot, and wind-up windows, it’s also the most comfortable for long-distance touring. FHCs are the most affordable and arguably the best value.

What to Look For

Body and Rust

XK sports cars rust. All of them. The question is where and how badly.

XK120, Steel-bodied cars (1950-1954):

• Sills, rot from the inside out. The sills are structural. Push firmly along the full length, any softness is a serious issue.
• Floor pans, water enters through the footwells and sits. Lift carpets and prod thoroughly.
• Inner wings, mud and water accumulate around the top and bottom of the wings.
• Door skins, the bottom two inches of each door rot from trapped water.
• Boot floor, water leaks through the boot seal and sits.
• Scuttle (cowl), the area where the bonnet meets the windscreen frame. Complex construction that traps water and rots from within. Scuttle rot is one of the most expensive repairs on an XK.
• Rear shroud, the panel behind the doors, surrounding the rear wheels. Another water trap.

XK120, Aluminium-bodied cars (1948-1950): Aluminium doesn’t rust, but the ash frame underneath does rot, and dissimilar metal corrosion occurs where aluminium meets steel fittings. The ash frame must be inspected carefully, soft or crumbly wood means a frame rebuild ($10,000-20,000).

XK140 and XK150: Similar rust areas to the steel XK120. The XK150 is slightly better sealed but shares the same fundamental weaknesses. Check additionally:

• Windscreen surround (XK150), the one-piece screen is bonded in, and water leaks behind the chrome surround rot the scuttle.
• Rear wing-to-body join, seam corrosion is common.

Deal-breakers: Scuttle rot, structural sill failure, rotten chassis rails (XK120/140). Any of these alone can cost $10,000-30,000 to repair properly.

Mechanical Inspection

Engine (XK Twin-Cam Six):

• Oil pressure: Minimum 40 psi at 3,000 rpm when warm. Below 30 psi indicates bottom-end wear, big-end bearings, main bearings, or both. Rebuild cost: $10,000-20,000.
• Timing chain: Listen for front-end rattle at idle. The XK’s duplex chain and tensioner wear over time.
• Cylinder head: Check for coolant loss, white exhaust smoke, and emulsified oil. Head gasket replacement: $3,000-6,000.
• Carburettors: Twin SU H6 (XK120/140), twin SU HD6 or triple SU HD8 (XK150S). Check for smooth piston operation, fuel leaks, and worn throttle shafts.

Gearbox:

• Moss gearbox (XK120, XK140, early XK150): No synchromesh on first gear. Learn to double-declutch. Crunching on second means synchro wear, rebuild: $3,000-5,000. Whining indicates bearing wear.
• Overdrive (if fitted): Should engage cleanly on the overrun. Failure to engage is usually electrical (solenoid) or a worn cone clutch.
• Automatic (XK140/150): Borg-Warner DG unit. Check for smooth shifts and no slipping. These gearboxes are rebuildable but specialists are becoming scarce.

Brakes:

• XK120/140: Drum brakes all round. They work adequately when properly adjusted but fade badly under hard use. Some owners upgrade to disc brakes, this is a common and reversible modification.
• XK150: Dunlop disc brakes all round. Check disc thickness, pad condition, and caliper operation. The Dunlop calipers can seize if the car sits unused. Caliper rebuild: $400-800 each.

Steering:

• XK120: Recirculating ball steering box. Adjustment is critical, too loose and the steering wanders, too tight and it binds. Check for play at the wheel rim, more than 50mm of free play indicates wear.
• XK140/150: Rack-and-pinion steering. Check for oil leaks from the rack seals and for play at the steering wheel. Rack rebuild: $800-1,500.

Chassis (XK120/140): The XK120 and XK140 use a separate chassis. Check the chassis rails for rust, cracking, and previous repairs. A rotten chassis requires either professional repair or replacement, $5,000-15,000.

Interior and Trim

• Dashboard: Walnut veneer that cracks and lifts. Restoration: $1,500-3,000.
• Leather seats: Check for cracking, splitting, and collapsed springs. Full retrim: $3,000-6,000.
• Hood/Soft top (OTS/DHC): Check condition and fit. A new hood costs $2,000-4,000 fitted.
• Chrome: Rechroming the full set of brightwork costs $5,000-15,000 depending on condition.

Price Guide (2026 AUD)

XK120

Condition	OTS (Roadster)	DHC	FHC
Project / non-runner	$60,000-100,000	$40,000-70,000	$35,000-60,000
Running, needs work	$100,000-150,000	$70,000-100,000	$60,000-90,000
Good driving example	$150,000-220,000	$100,000-150,000	$90,000-130,000
Fully restored	$220,000-350,000	$150,000-250,000	$130,000-200,000
Alloy-bodied (OTS)	$400,000+	,	,

XK140

Condition	OTS (Roadster)	DHC	FHC
Project / non-runner	$50,000-80,000	$35,000-60,000	$30,000-50,000
Running, needs work	$80,000-130,000	$60,000-90,000	$50,000-80,000
Good driving example	$130,000-200,000	$90,000-140,000	$80,000-120,000
Fully restored	$200,000-320,000	$140,000-220,000	$120,000-180,000

XK150

Condition	OTS (Roadster)	DHC	FHC
Project / non-runner	$60,000-100,000	$40,000-70,000	$35,000-60,000
Running, needs work	$100,000-160,000	$70,000-110,000	$60,000-90,000
Good driving example	$160,000-250,000	$110,000-170,000	$90,000-140,000
Fully restored	$250,000-400,000	$170,000-280,000	$140,000-220,000
XK150S 3.8 OTS	$350,000-500,000+	,	,

SE/Special Equipment specification adds 10-15% to values. C-type head (XK140) adds 15-20%. Matching numbers adds 20-30%.

Running Costs

• Annual service: $1,000-2,000 (oil, filters, carb adjustment, points, plugs, grease nipples)
• Insurance: Agreed-value essential. $2,000-5,000/year depending on value and usage.
• Tyres: 6.00 x 16 (XK120) or 6.00 x 16 / 185VR16 (XK140/150). $400-600 each.
• Unexpected repairs: Budget $3,000-8,000/year for a regularly used car.
• Specialist labour: $120-200/hour. The XK engine demands specialist knowledge.

Final Advice

Buy the best car you can afford. With XKs, the purchase price is the smallest part of the equation, restoration and repair costs dwarf the difference between a rough car and a good one. A $150,000 XK120 roadster that’s been properly restored will cost you less over five years than a $60,000 project that needs everything.

Get a pre-purchase inspection from a Jaguar XK specialist. Not just any classic car mechanic, someone who works on XK engines and understands the specific failure modes of these cars. The inspection fee ($500-1,000) is trivial compared to the cost of buying a lemon.

If you’re buying your first XK, consider an XK140 FHC. It’s the most practical body style, the rack-and-pinion steering is a genuine improvement, and prices are more accessible than the roadsters. Once you’ve learned the car, you can always trade up.