Air intake horn bolt size

Looking to see if anyone has the correct bolt size for all 5 bolts that hold the stock air intake horn down (4 on grid heater, 2 long, 2 short and 1 on intake plenum plate) Motor is a 98 12 valve. I believe they are 8mm but cant find the correct length and pitch as i don't have one to compare to and the search function turned up nothing.

any help is greatly appreciated.

Thanks in advance.