Fellow First Gen Firebird owners,

I need your help determining the original type and size of the tires that my Firebird came from the factory. Did the Firebird originally have White or Red stripes and what was the tire size? What that tire size convert into today’s numbers? Please offer any suggestions that you have on what my next set of tires should be. Many thanks!

Per the PHS documents (picture 1), the price sticker invoice says “E70X14 WSW Nylon”.

However, under the options in groups and accessories (picture 3), 33/5 says “E70X14 Red stripe wide oval tires.” Then under 71/72 it shows HD, which says “E70X14 White Stripe Oval.”

On picture 4, is has unintelligible writing next to the size “8.85X14.”

I read that yours rolled out of the factory with E-70-14 nylon white side wall wide ovals.
The free "HD" option in the billing sheet col 71-72 overrode the standard red stripes. (Note similarly the standard 3 speed manual overridden by your 4 speed.) The picture 4 stuff you are reading are under Pontiac Special Equipment, not Firebird.

Thanks Jim! Any suggestions on a brand of tire that's close to original? Is the E70X14 equivalent to today's 195/70/14 or 205/70/14?

205-70-14's are probably close to the original size. They are a little small in my opinion. I had that size on the front of my 67 for a while. Right now I'm running 215-70-14 which in my opinion is the optimum size. They look good and no rubbing. I've seen 225-70-14's on birds and they look too big. I've got those on my 69 goat and they look good on a car that size. These are the 215's:

Best to ask a good tire shop but I suspect it would be the 205/70-14.

I can't say from experience because the '68s went to the F70-14s. Over the years I ran several different 14" sizes and styles (white, red, raised letter, and even snow tires) as tires evolved.
Personally, mine came from the factory with WSW rayon radials but, despite my quest for originality, now run the Coker repro redlines because I like the look on by car. I rationalize it by the fact that redlines were a '68 factory tire, just not "as built" on mine.

205's are pretty close to original size. but they look a bit like bicycle tires.

I run 235's on mine to look better. You can go wider still, but then really start looking non-original in a hurry.

And I agree your originals would have been white sidewalls.

You don't want to put 60 series on 14X6 wheels. The tires feel squirrely in turns. I have experience. Maybe 14X7

Thanks for the feedback! I’m looking for the original 205 70 14 white wall 3/8, but that’s not a common size. The 215 70 14 is much easier to find, but it’s not the original E70-14 size. I really like original, so do you think the 215 is close enough?

Yes. 225 is where you start to see the difference. So 215 wpuld be good. I think Diamondback sells the 3/8" white stripe. I run Diamondback IIIs on all my 'birds.