The New Holland T8.420 tractor engine horsepower is 367 hp | 273.7 kW, PTO horsepower is 305 hp | 227.4 kW, and the drawbar horsepower is 255.76 hp | 190.7 kW.
Engine HP367 hp | 273.7 kW
PTO HP305 hp | 227.4 kW
Drawbar HP255.76 hp | 190.7 kW
PTO Transfer83.1%
Displacement531 ci | 8.7 L
New Holland T8.420 Horsepower Specs
Engine gross horsepower
367 hp | 273.7 kW
PTO horsepower claimed
305 hp | 227.4 kW
PTO horsepower tested
351.68 hp | 262.2 kW
Drawbar horsepower tested
255.76 hp | 190.7 kW
New Holland T8.420 Useful Horsepower Calculations
PTO-to-engine power transfer
83.1% of engine hp reaches the PTO
Drawbar-to-engine power transfer
69.7% of engine hp reaches the drawbar
Drawbar-to-PTO power ratio
83.9% drawbar hp vs PTO hp
Engine size per PTO horsepower
1.7 ci per PTO hp
PTO horsepower per liter
35.1 PTO hp per L
Engine size per engine horsepower
1.4 ci per engine hp
Engine horsepower per liter
42.2 engine hp per L
Rated speed per PTO horsepower
6.6 rpm per PTO hp
New Holland T8.420 Engine Specs
Engine type
turbocharged intercooled diesel
Displacement
531 ci | 8.7 L
Bore and stroke
4.606×5.315 inches | 117 x 135 mm
Compression
15.9:1
Emissions
Interim Tier 4
Rated RPM
2000
New Holland T8.420 Fuel, Cooling, Starting & Service Specs
Starter volts
12
Battery volts
12
New Holland T8.420 Horsepower Comparison Charts
Engine horsepower comparison
This model
367 hp
Average
210 hp
Low
120 hp
High
380 hp
PTO horsepower comparison
This model
305 hp
Average
175 hp
Low
100 hp
High
320 hp
Drawbar horsepower comparison
This model
255.8 hp
Average
150 hp
Low
85 hp
High
280 hp
Displacement comparison
This model
531 ci
Average
520 ci
Low
360 ci
High
750 ci
Rated RPM comparison
This model
2,000 rpm
Average
2,100 rpm
Low
1,600 rpm
High
2,500 rpm
Engine size per PTO HP
This model
1.7 ci/hp
Average
3.3 ci/hp
Low
2 ci/hp
High
5.2 ci/hp
Benchmarks use practical low, average and high ranges for the large ag tractor category. Use the operator manual and actual engine/tractor configuration before sizing implements or judging working power.
New Holland T8.420 Horsepower FAQ
How much horsepower does the New Holland T8.420 have?
The listed engine output is 367 hp, above the 210 hp benchmark average. That is a higher-power result, so ballast, tire setup and implement width matter if you want to use the full 367 hp.
How much PTO horsepower does the New Holland T8.420 have?
The listed PTO output is 305 hp, above the 175 hp benchmark average. That is the number to use for mowers, balers, augers, pumps and other PTO tools that need up to about 305 hp.
How much drawbar horsepower does the New Holland T8.420 have?
The listed drawbar output is 255.8 hp, above the 150 hp benchmark average. That makes the 255.8 hp drawbar number more useful than engine hp for tillage and heavy pulling.
How much engine power reaches the PTO on the New Holland T8.420?
The PTO-to-engine transfer works out to 83.1%, from 367 engine hp to 305 PTO hp. That is a normal usable range for judging PTO implement fit.
How efficient is the New Holland T8.420 for pulling work?
The drawbar-to-engine transfer is about 69.7%, from 367 engine hp to 255.8 drawbar hp. That gives a more grounded pulling estimate than engine horsepower alone.
Is the New Holland T8.420 better judged by PTO hp or drawbar hp?
The drawbar output is about 83.9% of PTO output, comparing 255.8 drawbar hp with 305 PTO hp. That helps separate pulling ability from PTO implement ability.
How big is the New Holland T8.420 engine?
The engine displacement is 531 ci, close to the 520 ci benchmark average. It is close to the normal engine-size range for this horsepower class.
Is the New Holland T8.420 engine stressed for its PTO horsepower?
The engine has about 1.7 cubic inches per PTO hp, using 531 ci and 305 PTO hp. That is a smaller-displacement, higher-output style result.
How much PTO horsepower per liter does the New Holland T8.420 make?
The output density is about 35.1 PTO hp per liter, using 305 PTO hp and 8.7 L of displacement. Higher hp/L means more output squeezed from each liter; lower hp/L usually means a more relaxed engine tune.
Official information note
Horsepower and engine specs can vary by year, market, engine option, fuel system, test standard and tractor configuration. Check the operator manual, spec plate, parts book and official newholland.com website before buying parts, sizing implements or making repair decisions.
