For car engines, what is the conversion factor between cu. in. and liters?

1 liter = 61.02 cubic inches

2 liters = 122.04 cubic inches

92 cubic inches = 1.5 liters

Google is handy for conversions. I calculated the above by googling “92 cubic inches in liters”

Thanks. I knew about Google, but I thought that there could have been the possibility that these could have been measuring different things. That’s why I asked.
But now while we’re at it, is there any relationship between these measurements and horsepower?

All else being equal, more volume means more fuel burned means more energy. So there is a general relationship, not direct. There are a lot of other factors.

Today there are four-cylinder turbo engines that far outperform big V-8s of yesteryear.

For example:

Mercedes-AMG 2 liter turbo
416 horsepower

1971 Ford Mustang V-8 351 inch / 5.75 liter
266 horsepower

308 cubic inch (5 liter) 1951 Hudson about 142 horsepower.

My 3.5 liter (214 c.i.) 2010 Ford puts out 365 horsepower and with electronic tweaking it could get 470 horsepower.

More fuel burned equals more horsepower but only if the right amount of air is used. If there is more gasoline in the air/fuel mixture that can be burned, it comes out the tailpipe as black smoke/wasted fuel. A supercharger or turbocharger can up the air being used to create more power.
The octane of the fuel matters too. If the fuel can’t completely burn because the octane is too high, the result is a sluggish engine because all of the fuel being used cannot burn before the piston reaches the bottom of the power stroke (the point at which the exhaust valve begins to open.).
Supercharged and turbocharged engines have lower static compression ratios than naturally aspirated engines because the engine would destroy itself with the addition of the supercharger/turbocharger that produces a higher compression ratio while under operating conditions.
Also, it matters if you measure the horsepower at the rear wheels or at the flywheel.
Horsepower isn’t everything. A small block Chevy 350 may produce 400 horsepower but may only produce 200 foot pounds of torque. A large Diesel engine may be rated at 400 horsepower but will produce more than 2000 foot pounds of torque.
The length of stroke means a great deal in engines. A longer stroke produces more torque. Those old engines that @Tropical_Willie mentioned have a greater stroke and relied on torque not horsepower. Usually, an engine with more cubic inch displacement will have more of the torque that you feel at take off.
Also, torque is measured at low engine RPM, where it is the highest, whereas horsepower is measured at high RPM, where it is the highest.

Another thing to note: If you were to run your engine in the horsepower range, which is around 4500 to 5000 RPM, the engine would be screaming all the time. Regular driving means the engine operates between about 600 RPM (idle) and 3000 RPM with the maximum torque being produced at about 2500 RPM. So torque is more important than horsepower. (My old Chevy, with a 350” engine and automatic transmission, would upshift under full throttle at 5000 RPM, or first to second gear shift @ 30 MPH and second to third gear shift @ 90 MPH.)

OLD cars had in-line 6 cylinder or in-line 8 cylinder engines. Because the crankshaft is longer and heavier, an in-line engine has more torque that a V6 or V8 engine.
Big Diesel engines idle at about 600 RPM with a maximum no-load RPM of maybe 2000 RPM. They run between 1400 to 1900 RPM when working.

@kritiper My 2010 Ford EcoBoost V-6 produces 95% of its max torque at 1800 RPM (pretty flat from there up to max at 4500 RPM) and has an engine management system that controls all sorts of things (turbo boost pressure, individual timing for pencil coils for spark plugs, cam timing for valves and each cylinder’s direct gas injector) to maximize torque and horsepower.

Oh 120 MPH is 3000 RPM with 6500 “Red line” max RPM

@Tropical_Willie I assume you have a transmission with overdrive.
My old ‘62 Chevy pick-up had a 4:11 rear end and would do 3000 RPM @ 60 MPH. (4-speed manual transmission, no OD)
My ‘91 Nissan pick-up with a 2400 cc. in-line 4, no turbo, (5 speed manual with OD) produces it’s maximum torque at 2500 RPM.

Yes, overdrive gear in 6th is 0.742 also the axle ratio is 2.77.

My ‘69 Chevy ½ ton had 3:08 gears and would run 2500 RPM @ 60 MPH.

Great discussion. Thanks, everybody!