Topic: Wheel 16x7" for Mustang 1966

[wojtekqw]

Hi, I'm from Poland. My name's Wojtek. I have a question - I would like to put in my car wheels 16x7". They may have various backspacing - 4" and 4,25". Please, give me advice - which ones I should choose. I have original fenders and I do not want to use spacers, i.e.:

http://www.cjponyparts.com/american-racing-wheel-16x7-torq-thrust-ii-polished-1965-1973/p/W22/        -4"

http://www.mustangunlimited.com/itemdy01.asp?T1=MW167+01&Category=&catkey=EMUSTANG           -4,25"

http://www.mustangunlimited.com/wheel-tire-fitment.html    -  according to this table I should use 4,25" wheels. Why, in this case, for this car model there are also wheels with 4' backspacing? I plan to buy torq-thrust II.
Thanks in advance for your help. Regards Ponies 

[Soaring]

If you look at this chart, the 4.75 is about the widest and deepest spacing you are going to get  by with.  Even with that, you may have to add spacers. 
http://www.dodgestang.com/Tire%20Fitment%20Guide%2065-6.pdf

[wojtekqw]

According to the below table when backspace is 4,75"  ET will be on the level of 18 mm, with backpace 4" ET will be 0, and with 4,25" ET will be 6.

https://www.rsracing.com/tech-wheel.html

Why then should I buy wheels with backspace 4,75" and use the spacer, if I can buy a wheel with lawer backspace? For my Mustang normally I should use wheels 16x7" backspace 4,25" according to the table:
http://www.mustangunlimited.com/wheel-tire-fitment.html

The question is if I can use backspace 4" instead of 4,25". I would like to lower ET not to increase it as backspace should be used at higher ET.