Is there any special headers or manifolds better than stock on a 88 300. I planed to put new manifolds on just seeing if theres anything better that will fit right up to the stock ypipe. Thanks. Dont know much about exaust

 

Apparently the stock manifolds are the best for flow, so people have told me.

 

rom personal experience, usually anything stock on an exhaust could use improving. Manifold->header, cat-> race cat or catless etc. Most exhaust manifolds are heavy and have poor to ok flow. Most aftermarket headers fix the weight and flow issues. If you don't want to buy headers or want to keep the stock look, you could always port match and/Or polish you stock manifold to improve flow. That's the cheapest way...

 

Pretty well proven on this forum and others that the stock exhaust manifolds flow better than anything aftermarket for the I6. I did allot of research after finding a set of headers for a few bucks. Not sure why, but that seems to be the consensus.

 

I stand corrected...

 

Not correcting you......I don't get why a cast manifold flows better than a header designed for better flow, but that was my findings or at least a majority opinion.

 

My sediments exactly. I didn't think cast (stock) would out perform a cnc machined, mig/tig welded tubular part... If it flows better, it flows better. Then if you went to a header, you would be losing performance but saving some weight...

 

The best flowing manifold for the 300 is the HD series manifold from the late 70's it is proven to outflow headers since it was designed for higher reving 300's used in fleet applications. Just make sure you get the HD log and not the plan stock truck log. Otherwise just stick with efi manifolds.

 

Ok thanks guys. Guess ill probly grab a new set of stock manifolds. These look fine just dont want them to leak in a few miles sfter i put the motor in and it looks like a pita to change them with everything on

 

My stocks are leaking at the manifold to tailpipe connection. Contemplating going with the hedman headers. I know you need to put in a bung for the o2 sensor, but how about the egr tube? I also don't have the air pump so I'll prob remove the rake assy, anybody know the thread size for plugging?