Bought a set of exhaust manifolds and ran the #'s. They come up as being labeled POLICE. Any difference in them than any others?

What are the casting numbers?

353030 3994045

353030/3994045 1973-1975 454 215 HP Police
Manifold made of nodular Iron for higher materil strength, but no mention of improved or decreased flow over earlier models.

I did a search of these part numbers and unfortunately John, you may have a fit problem as these are off a Impala or caprice.

One side will work, the right side will hit the firewall as these are from a full Size car.

http://www.chevelles.com/forums/showthread.php?t=35713&highlight=3994045



Tech team quote:

It will fit the engine with no promblems. How ever you will need to have your pipes made & indtalled at a exhaust shop to keep it from hitting the firewall, I have as friend that used a set of the 74 model manifolds on a 67 chevelle & his exhaust system had to be modified a lot to work, he had some promblems on the drivers side too with the exhaust being too close to the oil filter, I would look around on E-bay & find the right ones if I could.

My 67 has the same set on a 454 and I can find no firewall clearance problems and nothing too exotic about the exhaust. Would they create a bigger problem on a 69 than a 67? I have only $75 in these delivered,blasted, painted and machined smooth so I will wait and see what problems exist before I pay a premium for correct ones.

The good thing is there is no fresh paint or front end sheet metal on car so trying these will not create a hardship.

part #353030 N (nodular) RH (for 73-76 454 applications) recently sold one for $45 on the ebay auction site. LH side may crack more often they seem to be rarer.

Bought a set of exhaust manifolds and ran the #'s. They come up as being labeled POLICE. Any difference in them than any others?

Typically it means for commercial HD use police & taxi.... cars that are run 3 shifts a day and idle ALOT. THey genrate alot of heat. There is probably ly no performance enhancement over the standard ones... just the ability to soak in the heat. The 454 of those days made little HP. And yet they still crack??? Go figure.