Without knowing what it smells like and what your mods are, it's a hard question to answer or help with. It could be something, it could be absolutely nothing.
A sweet smell could indicate coolant getting into the combustion process. You don't want that.
A rotten/sulfur/egg smell could indicate improper fuel mixture (sensor related, intake air leak) or a catalytic converter going bad.
A strong exhaust smell but your car has no catalytic converter could be completely normal.
Can you provide more information? Does your car burn oil? Does it run okay normally?
Thanks. Yes I woulkd say it runs great. 209K milles. I really doint hit lift hardly ever. Mostly hit it some lately cause i just did lift bolts and lift screen a week or so ago. So been sort of testing it out....lift is definietly strong and better than before. Smell just seems like exhaust.
I would say no to burning oil....Now Ive never had anyone drive behind me and watch for tiny puffs of smoke on changing gears or shifting or lift....But ive certainly never seen even a remote puff looking in the mirror. Any oil loss is mostly due to dripping and even that is very negligable. Honestly Ive never added any oil between oil changes except last month and that was only a tiny bit. Moslty been tryinf to track that down....chain tensioner o ring and timing gasket and seals on the way.
74aces.....Yeah, I pondered the donut....perhaps theres more exhaust/pressure at higher revs/lift? Causing an otherwise unnoticable leak to be more noticable? And....If I am possibly going to have to unbolt the ex manifold when I do the timing cover do to that air pipe....well maybe i should shange the donut and ex gasket,,,,