Hard to say as we have little to go off of on how the Goku that fought Shura compared to his post-Karin and 22nd TB selves. Considering Yamcha wouldn't be massively stronger than the former though, I'd probably give it to Shura since this seemed a decent length of time into Goku's training, assuming the Kamehameha is restricted for obvious reasons.
Animelover5487 said:
If all it took for Goku to defeat Shula is temporarily blinding him with the KHH than I don't think Shula was much stronger to begin with
Except he didn't defeat Shura. All he did was distract him long enough to rescue the princess and escape in time. By that logic, Kuririn "defeated" Dodoria by blinding him with the Taiyoken and completing his objective of escaping. Goku even said afterwards that he was no match for Shura and only escaped through the lucky coincidence of Shura not being used to such bright light.
and Yamcha has better techniques than him like the WFF.
Wouldn't say what's essentially a flurry of palm strikes is a better technique than the Demon Spiral Fist. The Kamehameha would obviously give Yamcha the edge, though that depends on whether or not it's being restricted in this scenario.