To me, 8 months is still a bit young to branch off from the various baby cereals, veggies, fruit, yogurt. Have you introduced all the cereals, besides rice? Have you tried avocado yet? I
When my daughter was 8 months, I think I was targeting 32 oz (4 bottles) plus nursing morning and evening (she self weened at 9/10 months). If I can remember right, I think she went to 24 oz when she was 11/12 months and 16 oz when she was around 18 months. At 4 years, she still drinks 16 oz of diary each day.
Egg noodles and whole wheat noodles will also provide more protein than regular white flour pasta. In fact anything that you can give him that is whole wheat will give him more nutrition than items made with white flour.
One of the things I made for my daughter was to give her cheesy egg yolk balls. And this suggestion totally depends on whether you have any egg allergies in your family history, because if you do, then you'd want to avoid giving eggs until later.
I would take 1 egg yolk (you have to separate it from the egg white. Don't use the egg white because it has more food allergens), scramble it up with a little dash of formula, add some mild grated cheese, microwave it for 15-ish seconds, mix it up (decide whether you think it needs a few more seconds in the microwave), them take little spoonfuls and roll into a dime size balls. My daughter loved these... I'd even spread some on *no salt* tortilla chips and she'd gnaw on them. (Speaking of no salt tortilla chips, I'd also make some chicken salad with only canned chicken and a bit of mayo, and spread that on the chip also... but again, mayo is made with egg yolk, so you need to do some research on egg allergies and if you do introduce eggs, do it *slowly*.)
By the way, this website (http://www.wholesomebabyfood.com/eggsbabyfoodrecipes.html) says "Most pediatric resources agree that egg yolks are fine for <the non-allergenic> baby to eat when baby is around 8 months old. Please keep in mind that the egg whites should not be fed to baby before 1 year old." It also has some recipe ideas of what you can mix with egg yolk for your baby.