How much better are headers ?

[Checkmate]

How much better are headers than jacketed logs?
Are logs better flowing than a manifold on a car?
Is there a performance difference between thru hull and OT headers?
The reason for the q's is that I am tossing around the idea of going with headers instead of the losg I have now, but I have a nice hood over my engine and would prefer to keep it. If thru transom headers do not make a big difference over the logs, then why waste my money.
Thanks for any info, Dan

[Blown 472]

Originally posted by Checkmate
How much better are headers than jacketed logs?
Are logs better flowing than a manifold on a car?
Is there a performance difference between thru hull and OT headers?
The reason for the q's is that I am tossing around the idea of going with headers instead of the losg I have now, but I have a nice hood over my engine and would prefer to keep it. If thru transom headers do not make a big difference over the logs, then why waste my money.
Thanks for any info, Dan
First off you would have to remove the cover even with thru transom headers. I did not notice any gain in mph or rpm when I switched from center rise water cooled manifolds to jacketed headers, just a lighter wallet. Your results may vary.

[FryJet]

On a mild 460 in my Challenger I was turning 4700rpm with logs and when I switched to Basset twist headers it gave me 400rpm (5100rpm) without doing anything else. Well worth it in my book if you want the noise and you have the boat for em.
F.J.

[HBjet]

Originally posted by Blown 472
First off you would have to remove the cover even with thru transom headers. I did not notice any gain in mph or rpm when I switched from center rise water cooled manifolds to jacketed headers, just a lighter wallet. Your results may vary.
You didn't notice any change at all from logs to jacketed headers?
HBjet

[HalletDave]

Originally posted by Blown 472
First off you would have to remove the cover even with thru transom headers. I did not notice any gain in mph or rpm when I switched from center rise water cooled manifolds to jacketed headers, just a lighter wallet. Your results may vary.
Randy,
I am thinking possibly not seeing much difference over "center rise" logs.
Snail shells, that's a different story.
I have never made the switch so I don't know for sure.;)

[Checkmate]

Why would I have to remove the hood for the thru t's ? Do they rise up over the engine or something? Also, since it was mentioned, is there a difference in center risers than the ones I have (I guess end riser)? Thanks again

[Danhercules]

The reason you cannot run through transum headers is cause of the heat, am I right on this?
What about the Lighting water jacketed headers? You can run those under a cover, right?

[Tinkerer]

Just about any type of exhaust manifolds are better than logs.
If you run water jacketed headers or water jacketed aftermarket manifolds you will always see an improvement over logs.
If you have a stock BB engine headers wont get you much of an improvement over center rise aftermarket manifolds.
But if you intend to soup it up go with the headers.
With a small block unless you intend to get real radical stick with the center rise high performance manifolds.

[Tinkerer]

I can get real good prices on LIGHTNING HEADERS.
PM me if interested.
Friend of mine sells them.

[LakesOnly]

Checkmate,
Unbelievable as it sounds, headers can net you as much as a 80HP gain over traditional thru-transom exhaust.
With thru-transom exhaust, my old motor would rev to 4800+ rpm, but with only a swap to headers, it would rev to 5200 rpm.
In answer to your othrer questions:
~~~Logs probably do flow better than factory exhaust on a car because it is generally less restrictive and shorter pipes to exit.
~~~As far as thru-transom headers, I have never run them but I imagine that over traditional thru-transom logs, they would provide gains similar to going to OT headers. But thru-transom tubular heades radiate tremendous temp and frankly I probably wouldn't get into your boat if I knew you had headers under a hatch (safety reasons).
Hope this helps,
LO

[Blown 472]

Originally posted by HBjet
You didn't notice any change at all from logs to jacketed headers?
HBjet
I have center rise manifolds and I thought the exhaust was why the motor would not pull any more rpm then the worn out broken ring smaller motor so I put a set of lightings on and there was no change what so ever, aside from being a major pain in the ass to install the chev header on the ford head and being louder. So I sold them and found the best 200$ I ever spent on the boat was a shoe from hi tech.

[Mohavekid]

I have'nt tried the logs to headers route yet so I won't comment on any increase from that change. The concensus amonst the group and the pros is that it will make a big difference.
If you go with water injected headers like Basset or Rewarder, they still r un very hot and are a fire hazard under an engine cover.
Center rise manifolds or water jacket headers like Lightning's are usually wider than the logs and can cause interference problems with the cover. Reading on Lightning's website, http://www.boatheaders.com/
it appears the Lightning headers are 36 inches wide. I measured my engine cover and it's 32 inches wide. I'd bey yours is a similar width.
Good luck.

[RedRocket]

I think an important point isn't clear. Center rise manifolds aren't logs. Any decent center rise manifold will outperform logs and there's a good chance they'll clear your cover. Logs are terrible for performance, most auto manifolds I've seen would slightly out perform them because they usually have somewhat of curved ports to direct the exhaust flow instead of hitting a wall. I went from logs to a more flowing manifold with short separate tubes and gained 150 rpm.

[mud duck]

You can have headers go through your transom as long as they are water jacketed. The ones that do go over the transom can be either water or dry. And you can get hurt on those hot headers if you are not careful. :eek:

[OMEGA_BUBBLE_JET]

I picked up 200rpm on the big end with going to a set of twisties. they sound awesome too!!! be careful they do bite. ;)
Omega

[TexasJet]

Lightning make a set that is 32" wide. That is the set I will be getting. That is the out to out dimension on my stock logs. They will line up perfectly.

[Mr Twister]

No RPM gain from logs to headers? Could it be the cam is advanced too far or heads are restrictive?

[matt1]

Originally posted by Mr Twister
No RPM gain from logs to headers? Could it be the cam is advanced too far or heads are restrictive?
what kind of eng do you have

[Mr Twister]

It was actually a question, not a statement. However, I run a PONTIAC 455.

[Blown 472]

Originally posted by Mr Twister
No RPM gain from logs to headers? Could it be the cam is advanced too far or heads are restrictive?
I dunno if you are asking me but the cam was degreed by me and installed per the cam card, exhaust side not that restirctive c9ve's with a little port work. I think what killed it was the shit box adaptors to mate the chev header to a ford head.

[Mohavekid]

Originally posted by TexasJet
Lightning make a set that is 32" wide. That is the set I will be getting. That is the out to out dimension on my stock logs. They will line up perfectly.
TJ, where did you find the 32 inch wide Lightnings? Their web site shows the BBC headers at 36 inches wide.

[RedRocket]

Mr. Twister, he didn't have logs , he had center rise manifolds, if he had logs he would've seen a big difference. Omega>> you had that 200 rpm gain with headers , what did you start out with logs or what? and how modified is your motor. I'm considering better exhaust too.

[OMEGA_BUBBLE_JET]

Originally posted by RedRocket
Mr. Twister, he didn't have logs , he had center rise manifolds, if he had logs he would've seen a big difference. Omega>> you had that 200 rpm gain with headers , what did you start out with logs or what? and how modified is your motor. I'm considering better exhaust too.
started out turning about 5100-5200 rpm on a mildly modified BBF making somewhere in the neighborhood of 463hp. had logs with snails with the 2 7/8" exhaust tips. Went to the bassett twisties and now top rpm is 5300-5400rpm. Going to put on my new 750 holley dp this season and see if it compliments the headers. Although I really don't want to push this Ford past 5500rpm if I can help it.
Omega

[TexasJet]

MohaveKid, Try the CP PERFORMANCE catalog or their web site. I haven't looked at the Lightning web site in a while but I thought they had the 32" headers listed.

[Mohavekid]

TJ, found the narrow ones in the CP web site.
Thanks

[AdrenelineOD]

I`m not a pro but this I do know logs rely on the piston to push ex. Headers are like a vacume, as soon as the ex. valve opens the ex. is vacumed out even befor the piston is doing much thus making more room for pure O2 and feul thus increasing everything (slightly on my boat) Quote me if I`m wrong. CHEARS!!!:D

[Taylorman]

What brand exhaust are these.
http://www.***boat.com/image_center/data/500/671P1310084-med.JPG