Found my gremlin this weekend vibration to be my muffler extension pegged on drivers side to body, now while looking find that the pipes are not in correct place for hanger bracket under transmission which is why it has radiator clamps in that area. Looking to get this fixed but also noticed two other things, the pipes before the mufflers have same clamps and pipes are practically touching each other on the bend not separate like I see others and passenger side does not have the heat riser, did these come with one and should I put that in? 

Okay found my BB exhaust pipes are incorrect, can someone comment on where to buy pipes with correct bends for 68 and if I need the heat riser or spacer?

Any of the Corvette venders will carry the needed and required parts for installation. Our sponsors can and  will give you a discount on them. Mention the site and support them. 

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I gutted my heat riser and blocked off the crossover.  If your car starts and runs fine when it is cold outside, I would leave it off.

Just an update, ordered new pipes from Zip arriving Thursday. Last thing for the year 😂