I have an old house, 88 yrs. I have a newer electric panel with breakers. There is also an old main shutoff in the garage with 2 70 amp fuses in it. I have not had an issue with my electric but while trying to sell our house the old shut off became an issue with the home inspector. He said it was a 70 shut off and need to be upgraded. My question is, with 2 70 amp fuses is the shutoff 70 amps or 140 amps?

You have a 70 amp service, do not add the two fuses.

Minimum size service is now 100 amp for new services or homes.

While your service was sufficient and per Code at the time of installation, and Code does not require anyone to upgrade to conform to the current Code, mortgage lenders and insurance carriers may require a service to be upgraded.

He said it needed to be upgraded? On what fantasy did he base this on?

A home inspector cannot tell you to upgrade your service. He can comment on it but that's about all he can do.

If the HI takes the position that the service my be upgraded or he will inform the potential buyers, then ask him to supply you with the NEC citation that he is basing this statement on.

He can recommend to the buyers that they consider upgrading the electrical service but that would be their choice, not your mandate.