Resurfacing a cyclinder head - GIF

[Frank S]

How long did it take to weld and not have it warp and was it worth repairing, it must be a special head with a five valve configuration.

I imagine the head may have already been warped beyond being able to be cleaned up was the reason for welding.
As for being a special head yeah, you could say that the list of manufactures who produced engines with 5 valves per cylinder is small.
Here is a wiki of those. What's interesting is Peugeot did it in 1921. There is even 1 known engine built with 8 valves per cylinder
Peugeot had a triple overhead cam five-valve Grand Prix car in 1921.[14]

In April 1988 an Audi 200 Turbo Quattro powered by an experimental 2.2-liter turbocharged 25-valve straight-5 rated at 478 kW/650 PS@6,200 rpm (217.3 kW/liter) set two world speed records at Nardo, Italy: 326.403 km/h (202.8 mph) for 1,000 km (625 miles) and 324.509 km/h (201.6 mph) for 500 miles.[21][22]

Mitsubishi were the first to market a car engine with five valves per cylinder, with the 548 cc 3G81 engine in their Minica Dangan ZZ kei car in 1989.[23][24]

Yamaha designed the five-valve cylinder head for the 20-valve 4A-GE engines made by Toyota for use in some Toyota Corolla models in Japan. Yamaha also developed five-valve Formula One engines, the 1989 OX88 V8, 1991 OX99 V12, 1993 OX10 V10 and 1996 OX11 V10, but none of these were very successful. For their YZ250F and YZ450F motocross bikes, Yamaha developed five-valve engines.

Bugatti (EB 110), Ferrari (F355, 360 and F50), Volkswagen - Audi (Audi Quattro) - Skoda (Octavia vRS) and Toyota (4A-GE 20V) have all produced five-valve-engined vehicles.

https://en.wikipedia.org/wiki/Multi-...0with%20Yamaha.