beatlesrcool1964

I'm looking into replacing my fuel sending unit on my 66.

The gas gauge still doesn't work and I narrowed the problem down to this by grounding the wire and checking the gauge.

My question is:
Does it matter if I get one that has a 3/8" or a 5/16" fitting?
The unit will connect to the fuel line with a hose so as long as the hose is clamped I would think it would be fine, but of course I want to check this before I purchase.

I'm only considering the 3/8" one because it is about half the price of the "correct" 5/16"

Thanks for any advice. Also, if you know about electrical, please read this thread, I'm still having troubles (getting close tho!!):
https://mustangforums.com/forum/clas...-problems.html

rmodel65

3/8 flows more fuel..which in turn supports more power for mods etc..

sure the actual sending unit is bad? every classic ive had the sending unit was still good the float that hangs on the end was corroded and had taken on fuel and wouldnt float anymore..

beatlesrcool1964

So then I wouldn't need to modify anything to get the 3/8" correct?
More power would be great. I have the 200 with a 2v Carb and still struggle driving up a grade.

'm not sure yet if it is just the float, I hope it is. I have to wait until I get a container to empty the gas into.

In case it isn't just a hole in the float I want to figure out what to buy now.

2+2GT

You should get the correct size for your car. BTW, the more expensive units have the advantage of actually having the right electrical value. If you want a gauge that reads 8 gallons off, go with the cheap one.

As for the size of the pipe, the 67 Shelby with the 428 dual-quad engine used the 5/16" version. So, what are you driving?

beatlesrcool1964

I'm driving a 66 200ci

I was going for the cheapest one because the description said "the most accurate unit we've tried" so in my mind it was a double win.

Stangatic

3/8 is more so needed when you are doing EFI or having a power adder, (500+hp range) . I don't think you would out power the stock 5/16 on the 200ci.

Your power starvation is not caused by the lack of gas, but the lack of power. When going up hill, is the transmission down shifting? That could also be your issue too. Make sure the transmission kick down is adjusted right.