Exhaust

If it is a raw gas smell, then check under the gas tank up front for any leaks.  Remove the front passenger side wheel for easy access to check on things.

If it is an exhaust smell, then make sure that the engine heat shields are in place (if you open the engine hood and look down in there, you should not be able to see the ground).  Re-check the exhaust fittings everywhere for leaks (you might see some carbon shadows on the tubes if they’re leaking....maybe).

What type of exhaust system do you have?   Some exit right out the back and some exit off to the side.  Straight out the back seems to minimize smells, but not always.  

Give us a little more detail about the exhaust system and maybe we can help more.  I have the rear seat covered by a tonneau cover and only get the exhaust smell when I stop for a light or stop sign and then almost always.  
So you smell exhaust always while driving or just when you pull up to a light or stop sign?

Also, if you have Weber carbs the floats are open to the atmosphere, so some gas smell is normal. "Heavy" is not normal, however.

Thank you. Will look into these

I have a Spyder so this may not translate, but my gas smells usually come from the filler neck gasket or a cracked vent hose. Try as I might, I've never been able to seal the filler neck so that it doesn't leak a little when I fill the tank too much. 

One of the reasons I'm having an aluminum tank built. 

I kept smelling gas from the MG TD replica I'm working on. Tracked it to the filler cap, which was ill-fitting. Closer inspection revealed it was ovoid. Pulled the tank, drained it, let it sit upside down in the sunshine for a couple of weeks, then blew fresh air through it with my shop vac for several hours. Applied my trusty tailpipe expander, it opened up cracks in the weld. Ordered a filler neck that looked like it would fit from Summit Racing. Cut the old neck at the weld point, it was all cold joint and fell apart. That's what you get when you try to weld a tank filled with water. Fit the new neck to the tank and brazed it in. Tricky because it's  much thicker than the sheet metal. Not my prettiest work, but it's sealed and looks okay with paint applied. Added a vent because the new cap isn't vented. Haven't got it installed because I'm still working on patching and sealing the firewall.      

Wow!  somebody else who does cool-looking welds like I do!

Hey, if you can dress it up with some bondo and paint it nice and it doesn't leak, then you're golden!

@Gordon Nichols posted:

Wow!  somebody else who does cool-looking welds like I do!

Hey, if you can dress it up with some bondo and paint it nice and it doesn't leak, then you're golden!

Don't be silly! That's a perfect spot for JB Weld and some spray paint.

In the past I would send the tank out to have the neck shortened and the vent moved, that became a costly adventure. I came up with a cheap fix,  cut the neck off leaving about 1/2" at the tank end and same at  the cap end.  Get a exhaust pipe adapter from Auto Zone that will fit INTO the tank neck and the other end will accept the cut off neck into that . Cut it down as needed so that will fit test fit INTO the tank's shortened neck. Drill the shortened neck for a small vent, scuff all areas & clean the bare metal. Bush on JB Weld to the short neck section and the lower portion of the adapter do the vent also at this time.  Tap it with a hammer and wood block into the tank neck and smooth the JB Weld .  Slide the cap end of the cut neck INTO the other end of the adapter again secure with JB Weld. This takes less than an hour to do. 

ive never had any luck with JBweld,,if duct tape cant fix it then it stays broken or i will get it fixed by a pro..

@barncobob posted:

ive never had any luck with JBweld,,if duct tape cant fix it then it stays broken or i will get it fixed by a pro..

The exhaust extension piece is close to a press fit, the JB just seals the seams.

Why is it I always get these great tips AFTER I did something the hard way?