Lightning Project for Halloween

I'm going to help building a Kit and it requires a Radio Shack #276-1000 triac. All I can find for Data on the part is this:

6-Amp Triac/Thyristor
(276-1000) Specifications Faxback Doc. # 37468

Current (Max): .................................................. ..... 6 A

Current (gt)(Max): .................................................. 50mA

Voltage (Max): .................................................. .... 400V

Voltage (gt)(Max): .................................................. 2.5V

Case Style: .................................................. ....... MU27

Pin-Out with pins facing you and reading left to right: ........ 1=Anode 1
2=Anode 2
3=Gate

I'm wondering if I can replace it with a 8 amp Thyristor? Here is the schematic. If so, what parts do you think will have to be added ?