My house is 50'X 25" block. The top of the rafters lie 5 inches above the block. The roof overhangs the block by 1". Had concrete tile roof, had replaced with shingle and had largest roof vent possible along the ridge.
I have 2" holes for intake ventilation in the 3"X22" board that is above the 2" board which lies directly on the block.
Do I have enough intake ventilation if I just clear out the old holes encrusted with paint, etc. and put in some kind of insert?
My attached garage "unfinished" and ceiling is open to the entire roof/attic and the other end of my house only has the 2" holes. There are two holes between each rafter. Thanks, Man!
Tom in St. Pete

I assume you've installed a ridge vent at the peak of your roof. If so, that should equal approximately half of your total vent area. Therefore, the soffit vents should equal about half of the net free area of the ridge vent. Two-inch screened holes won't do it. Two 6-inch diameter Mini-Vents in each rafter bay might be enough. Other choices are a one-inch wide continuous screened vent, or remove the wood soffit and replace it with a vented vinyl soffit. Some are made to look like beaded wainscot boards, with the vent holes concealed in the shadows of the beads.

I don't know how much snow you get in St. Pete, so the winter venting of your roof isn't so critical as it would be here in the north, but I imagine you have many days of high heat and humidity, so proper venting is still important.

If you have 2" Fasica vents between each rafter as long as these are not blocked with insulation and paint like you said, you should be ok.
Why would you remove a concrete roof and replace with asphalt? Does not last nearly as long as the concrete tiles. I assume cost was the factor?

Yeah, the roof was starting to leak, was 55 years old and the concrete tile was deteriorating, the underlayment was going fast.
Cost was the biggest factor for replacing the concrete tile with shingle and is the way everyone else on the block is going even though houses here have gone WAY up and just a little down lately.
I was certainly hoping to just replace the round vents, they are in a three inch board between the rafters and above the 2" laying on the block. I couldn't make them any larger round but could do the rectangular thing mentioned as long as it was 2" wide like the holes, or replacing the entire board with a vent/screen.
With the entire 25' end of the attic open to the garage (venting?) you still think the two 2" holes are insufficient (or sufficient, lol)? What I'm dreading is cutting larger holes or squares, doesn't seem like a simple do it yourself kind of job like replacing the screens.
House had no ridge vent at all before!!...???
Now has 24 feet Cobra III ridge vent.

Yes, it's quite muggy and hot almost all the time spring through fall here, no concerns for winter weather. I was told my energy bill would go up replacing the roof, but my A/C is working better already, probably due to the ridge vent?
Thank you folks for your advice

OK, the Cobra 3 ridge vent has 18 square inches of net free area for each foot of length, so there are 18 x 1.21 or about 22 square inches of net free area in each rafter bay. Therefore that's what you should have in the soffit, also.

A two-inch hole, even if completely open, has 3.14 square inches of free area. Put screen in it, and that drops by nearly half. Two holes in each rafter bay provide about 3.5 to 4 square inches net free area (if screened), leaving you about 18 square inches short of the recommended net free area. That's why I said that two holes wouldn't cut it.