UC chances

Of all the UC’s, which can I get into easily with a 3.4 GPA, a 1270 SAT and strong, but few extracurriculars? Which will be a stretch, but still (maybe if I’m lucky) possible? Which are completely out of the question?

3.4 GPA is your UC GPA, unweighted GPA??? https://rogerhub.com/gpa-calculator-uc/
Intended major?
Competitive majors will require higher stats than less competitive majors.

Based on your 3.4 GPA and test scores only:

Freshman admit rates for UC GPA of 3.40-3.79:

UCB: 2%- Reach
UCLA: 3%- Reach
UCSD: 6%- Reach
UCD: 15%)- Reach
UCSB: 14%- Reach
UCI: 13%- Reach
UCSC: 59%- High Match
UCR: 78%- Match
UCM: 92%- Match

Focus on the last 3 UC’s and if you are a California Resident, consider the Cal states such as Cal Poly Pomona, Fullerton, Sac State, Sonoma, Chico State, San Francisco State, San Jose to name a few.

You meet the base requirement so, none are out of the question. Understand, the chances at most of them is pretty slim. UCM is your best shot - and even there, more competitive majors are probably out. Apply to the ones that interest you and see what happens. Please also apply to several CSUs. What are you hoping to study and what are you looking for in a school?