Hello,
This is the first time I have posted on this site hope someone can help.
I own a '74. It was totally stock with original paint when I purchased it in 1990. I have done all the important upgrades in the 1990-1994 timeframe (suspension, brakes, cooling, air conditioning ... Including: Edelbrock dual plane manifold, Holley 4 barrel carb. with electric choke, Hall big bore headers, ANSA exhaust, electronic ignition (I think Hall called it the "show and go" package).
Recently I changed the stock "open chamber" heads for the "closed chamber". I use Hall Pantera's modified Ford electronic ignition and distributor. I set the ignition timing in accordance with the sticker in the engine compartment (approx. 16 degrees). Engine Vacuum is rough at idle but increases and smooths out at 1500-2000 rpm.
Now, I find that sometimes I get backfire through the carb when I try to start up a cold engine. As well, when I step on the gas to accelerate off from idle (about 700 rpm) the engine stalls as well as a carb backfire at times. At 1000 rpm this occurs less frequently and do not occur when I accelerate off with the rpm up at about 1500-2000. Do I have a timing problem? If so, what should I set the timing at because I do not have a stock set-up. I have seen another post on this site that stated I should be looking at my intake valve lash. I was quite sure I did a good job with the valves. But, if needed, I will give it a third look. Anything else I should consider?
Second question: I had replaced the A/C compressor with a rotary unit. The system was running R-12. My hoses (original) are now shot and need to be replaced. R-12 is no longer available in Canada (where I live). What can I expect if I replace the system with the new R-234 (I think that is what its called) or should I try to replace the hoses and try to get and stick to R-12?
I would be grateful for any guidance. I am more than a shade tree mechanic but less than a licenced one. I do all the work on my car. I only go out if I do not have the expensive tool (eg. hydraulic press).
Other than these issues the car is a beauty and I enjoy it very much. I use it as almost a daily driver (provided no rain and no snow). And ... it still has the original paint.
Thanks
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