Headers or Manifolds ?
 

I have a 29 scarab with twin 350 mpi's. It has the corsa quick n quiet but its not selectable. Its fixed 50/50 transom/outdrive. Looking for facts or opinion on what to do. Leave it the way it is, buy the adapter kit i've heard about to convert to 100% transom, good set of manifolds, or headers. Thanks

Re: Headers or Manifolds ?
 

I personally like a selectable exhaust, closed for sneakn' around and open for fun, or if anyone on the boat is yakkn' too much, when it's open they shut theirs.

Re: Headers or Manifolds ?
 

All engines respond well to better breathing exhuast system, but I have heard it said that small block Chevy's REALLY wake up to a decent exhaust system. I would suppose any aftermarket system like a Stainless Marine or a GIL system will work much better over a stock Merc exhaust system. I thought I saw a used set of GIL's for a small block Chevy in the classifieds section.

Re: Headers or Manifolds ?
 

am i better off with a set of hi perf manifolds or headers ?

Re: Headers or Manifolds ?
 

An aftermarket exhaust manifold system such as Stainless Marine or GIL ARE hi-performance exhaust systems. A full length tubular system would be even better yet such as Stellings, but they cost even more $$$ than the aftermarket hi-performance manifolds as mentioned above.

Re: Headers or Manifolds ?
 

very true

Re: Headers or Manifolds ?
 

I asked the same ? before getting my Revolution Marine exhaust. Problem is, there are numerous opinions and few facts. The only data/stats on performance I could find were from the various manufactures, which needless to say were bias.

I will tell you I saw little WOT gain, but got great mid range improvement. And I'm ok with that, considering the $ I spent.

Had I gone out and spent 3 times the amount on decent SS headers and seen no top end improvement, I would have been really pizzed off.

Good luck with your decision.

Re: Headers or Manifolds ?
 

thank you very much...boat currently has corsa quick n quiet with no captains choice so its fixed 50/50 transom/drive. looking for performance of course but also some sound improvement...

Re: Headers or Manifolds ?
 

Bern's,

You aren't really going to get much of a black/white answer to this. Obviously, you are the one who has to ultimately make up your own mind about what you want to do about an aftermarket exhaust system. As Kidnova said, if just adding hi-perf manifolds to a stock Merc engine, then you are probably only going to see minimal gains. Usually, people do notice more of a difference in the midrange which is where you cruise anyway. You may also notice a bit of an RPM gain. One thing that you can count on is that hi-perf manifolds and the stainless steel tailpipes that come with them will really dress up your engines nicely and they will add a little more rumble and thunder.

Also, one thing you should know is if you DO add some hi-perf manifolds and then decide to add more Hi-perf components at some future date, then your engines will respond much better to the mods because you have a better breathing exhaust. If it weren't true, then most everyone would still be running their Big Bad engines with the stock Merc exhaust system which is pretty crude at best---but they don't. I wish you the best as well.

Re: Headers or Manifolds ?
 

Lightnings are good choice for the money...
Not sure if they make them for SBC.

Re: Headers or Manifolds ?
 

Another thing to consider....do you boat in salt?? If so, not good to go with Revolutuions as they are aluminum. If your in salt I think you're stuck with cast or SS.

BadDog, I've also heard Lightning's are good for the money. Around $1700.00??

Re: Headers or Manifolds ?
 

i appreciate all the input....wonder if santa can fit them down the chimney and yes boat is now 100% salt use...unfortunately. luckily when i purchased it its first 5 years of use (160hrs) we are fresh water, but so far knock on wood it has responded well to the salt but then again its flushed after every use...

Re: Headers or Manifolds ?
 

Lots of comments, but no one mentioned that you will eliminate a "bunch" of weight. Also, you eliminate the water through the wall water joint as in all but brand new style stock Merc manifold/risers. That is, Stainless Marine, and all other performance oriented aftermarket brands use an outside water hose to get water from the manifold to the riser. Most see little speed gain, but you might see more than is considered average due to your particular stock setup. I recommend the long, through transom risers with no additional tips used if you think you will ever change cams. They allow for larger cam selection when reversion is an issue. Use the standard style risers with rubber hose to tips for other applications. Even if you intend on keeping your motors basically stock, the safer water passage and lighter weight will be worth the cost. Not to mention the much better looking setup. There are usually good performance manifolds and risers for sale used and you should have no problem selling your stock setup. I've used Stainless Marine for over ten years and they will probably outlast me. You can pretty much install them and forget about them. Not so with tubes.

Good luck.