My 72 cutlass with 350 has no RH manifold heat shield or hot air pipe.From info from this site,I think its from a '73.I capped off the crossover(it was previously an amateur job).Is it supposed to have this shield?

 

The "heat shield" is actually a hot air stove to feed heated air to the thermostatic air cleaner for quicker warmup. The stove is a separate bolt-on part that frequently rusts off or is removed if the manifold is ever taken off. You can sometimes find them on ebay.

 

2 things.

1. If you're asking if the 72 should have the "heat shield" on the passenger side, the answer is yes. It's part of the engine start and warming engineered into the thermal operated vacuum on the snorkel. On a cold start, the thermac (operated off vacuum) will snap the flapper on the snorkel closed. This allows heated air from the manifold to rise through the pipe to avoid icing up the carb in winter or on cold starts. As the car warms up, the thermac returns to a fully open position that closes the air pipe and allows engine temp air to be pulled into the carb.

2. If you've created a dual exhaust by blocking the drivers side crossover, that's fine. GM used to do that too. Does it need an extra "heat shield" on the drivers side? No. Even the cars with dual air snorkels ran a vacuum line from the primary snorkel to the second one. If your car just has the shielding on the passenger side, you have a completely normal 1972 350. Different years (post 72) of 350 and 455 put the heat shielding on different sides.
Hope this helps.

 

I have a heat riser setup if you need one.

 

Kinda on subject.

What do the 69 "W" cars have as far as a Heat stove? Does the dual snorkle still have the pipe leading from the heat stove to the air cleaner on the passanger side?

I've only seen on true 69 W-30 in person and was wondering.

 

Yes, the 68-69 cars had the passenger side hot air pipe. Note that 68 and 69 pipes are different.