The big hole is for the temp sensor. Then there others will be 1/8npt holes for vac lines and brake servo pipe. Depending on what management your using its best to change the inlet temp sensor to a fast reaction one and with the tps you will need to change that as well. But to get it running on stock. You will just need stock tps, stock iat sensor, vac line for map sensor, vac line for dv if running one, vac line for boost gauge. If you have a hole left over just bung it up