Just purchased a 67 Mustang coupe, with I'm told a 289 engine, another says no its a 302.
It has Eidlebrock manifold,4 bbl Holly carb. Headers and brand new dual exhaust system

Question 1
How do I determine which it is.. 289 or 302 ?

question 2
there is a lever extending from under the dash by the left foot, when you step on it the wipers come on, is this the normal wiper on/off switch or did it have wind sheild washers at some time?
 There are no washer nozzels anywhere, no washer bag or bottle, no lines to connect, no electric wires for washer pump.

Question 3
where do I find all this information for washer and missing accessories

I have a Ford Chilton book but don't find any answers
Thanks so much from anyone for any help you can offer
Larry  

You would do well to get a service manual for your 67 - it'll have all the info on the washer parts and where they go.  IIRC, the pedal triggers the pump to squirt fluid and at the same time triggers the wipers.  There should be a dash switch too.

Autokrafters is one source for the manual

302's appeared in Mustangs from the factory in 1968.  If it's the original engine, it's a 289.  With the 289/302 the only way to tell is to measure the stroke.  You can try using a very thin stick - remove the #1 plug and set the balancer to the TDC timing mark.  Put the stick end on the piston top and make a mark at the cylinder head or plug hole.  Rotate the engine 180 degrees, putting the piston at the bottom of the stroke.  Make another mark.  A 289 has a stroke of 2.87 inches, a 302 has a stroke of 3".  

Thanks a lot, I appreaciate your in put.

 Another question you might answer for me? should I use an octane additive to unleaded gasoline, or is it possible to change something so it uses unleaded without harming the engine?

Thanks again  

Do not waste any money on "octane" additives.  They are ineffective.  At best, you might get 1 or 2 points - that means you could raise 91 octane to 91.1 or 91.2.  Most do nothing.  You can run unleaded in the engine without problems as is.  It won't hurt it.  We run pump unleaded in the race cars, no additives.  After 2000 full bore drag runs, there is zero valve seat recession.  Valve seat inserts are a good way to sell machine shop services IMHO.  

many thanks, knowing this information makes my life a lot simpler all of a sudden.

Larry  

My shop guy says that the valve seat and valve work is the most important thing.  Of course, he's one of those guys that does a precision valve seat cut, then hand laps them in "just to be sure".  I'm sure there may be other issues if you get up in spring pressures, like roller cams and such.  But by and large I think it's not a big issue for most of us.