Are 295-40-20 to big for my car?
 

1973 Camaro, stock fenderwells. I allready have 20's on the back with 255/35/20 but it is just not enough tire for me. The rims are 20 coy's 8.5 wide what do you guy's think?

Are you getting new wheels?

I was not planning on it. Jason Wyrick's car is running that size on the back with a 10" rim. I did not know if 1.5 inch would matter that much or not.

I do not think they will clear very well. That tire is a full 29 1/2" tall. I know 29" slicks barely fit and 30" are to big. Also, the 295/ 40 is probably going to make your wheel well look over stuffed. A 275/35 ZR20 is 27 1/2" tall and is a pretty good height for your wheel well, and you may be able to reuse your rims even though most would recomend a minimum of a 9" rim.

I was just talking to a buddy of mine that suggested a 275-45-20 I am looking for more of a sidewall height than width.

I'm going to agree with Frank at Prodigy and that 275/35/20 especially being you are running an 8.5" wheel. Anything wider then that, and it just won't work well on that rim width. Not only will it not look right, it's just not safe.
Here's a photo of my 69 with the same tire on an old Budnik 20x8.5. Tire is a Nitto.

Jasons car does not have stock rear wheel wells. And his are still very full. He cut the stock inner and moved it over as far as he could I believe. He is also running a martz rear clip which gave him additional room