I have a 1984 28ft Wellcraft Excalibur with a stock 330hp 454 w/ BW trans and TRS drive. The manifolds and risers on the boat have unknown amount of years/hours on them and I want to replace them for this up coming season. I bought a set of the Lighting Headers for the boat and the boat allready has thru hull exhaust. The reason I picked up a set of headers is next winter iam planing on building a 502 based stroker motor and figured it would be a waste of money to buy another set of stock manifolds and risers and then next year buy the headers for the new motor. Well my question is will the motor loss HP or torque when I put these headers on? I know on Lighting headers website they claim the motor will pick up HP but I want to know what you guys think. Also will the exhaust be any louder then it is with stock manifolds and risers?
Thanks
Erik

Erik, I don't think you will experience any loss, but the gains will be very minimal too. You will only pick up a minimal amount of HP by bolting them on a stock Merc 330hp engine---maybe 15-20hp. Therefore, you may not see any gains in speed...MAYBE 1mph if that. However, you may see a nice increase in your RPM and midrange crusing speeds and/or torque.

Also, yes.....you the Lightning exhausts will sound much better than the stock Merc exhausts you have now---they will be louder...especially if they are a completely "dry" system/set-up.

Thanks KAAMA.
I just wanted to make sure iam not going to lose low end torque since it is a heavy boat with a single 330hp BBC.
These headers are a wet exhaust set-up.

I have lightniings on my 454. Did the same thing. Swapped them out when my indmar manifolds were getting really bad. I had updated my 330hp with the HO cam, rectangular port heads and intake. That really woke the 454 up. (heads and cam were a huge improvement, yet still mild).

Anyway, bolted the lightnings on a few years later and picked up 40+hp.
Sounded better, looked incredible, and picked up a few mph.

Same exact plan- I wanted nice exhaust, so that someday when my 454 let's go I'll replace it with a 502 or more and the new exhaust will transfer right over.

KAAMA is right, with the stock 330hp you may not see an improvement, but it will function well, look great, and may sound a little better.

Give some thought to the heads and cam. Do the aluminum rectangular ports and to bring your compression up. The heads can swap over to a 502 as well and will really wake it up in the meantime. just a thought.

I was thinking about doing a cam/intake/carb swap on my stock 330 BBC with the help of rmbuilder aka Bob Madara , but iam not pulling and swaping heads. I just have to wait till warmer weather so I can get the shrink wrap off the boat and see how bad it will be to remove the rear seat so I have room to pull the camshaft out. I dont want to pull the motor so if the rear seat comes out easy then I might just do the swap. I know if I swapped the heads it will make even more power but iam doing that to the 454.
Thanks
Erik

Which model headers did you guys run on your 330s?

Something like these http://cgi.ebay.com/ebaymotors/Light...ssoriesQ5fGear

I used a set of lightnings on a similar build up on a 330 454 that I had several years ago in my first Pantera & I was very pleased with them.. (they were the wet system & not the dry tailpipes) They fit really nice without any modifications.. Not sure about speed & HP vs the stock merc. but I have no doubt that they will better & will obviously help a more as compontents are added to compliment them.. I don't think thats your question , or intention but just don't buy them thinking you will pick up 3-5 mph as alot of people do... Not saying there are not applications where that has happened but thats not the norm. They sounded good but really weren't quite as loud as I thought they would have been...

Also keep in mind that the regular ones I think they call magnums (?) are stainless inner primarys but the outer tubes are powdercoated mild steel... (not sure if you are running fresh or salt ?)

Heres a quick basic rundown on my setup (off the top of my head ,its been a day or 2)

Pulled the motor completly down :
light hone
ofcourse all new gaskets , seals ect...
Forged pistons 9.4:1
Total Seal Gapless rings
Put ARP bolts in the rods
All new Clevite bearings
Sorry but I can't remember the cam specs at the current time.
Mild port job on the 049's (mainly blended in the bowls nicely , port matched the heads & intake , & just cleaned the up a bit throughout the ports)
Edelbrock performer 2.0 intake (b/c) thats what I had
750 holley
Harland Sharps 1.8:1 roller rockers

I'm sure I missed a thing or 2 here & there but you get the idea... Anyways it woke the boat up alot & was a completly differant boat to drive esp. in the midrange area.. The boat ran right around 60-61 on GPS before & ran right around 70GPS when I was done so that was a major improvement in opinion.. probably made in the 450-475 hp range

Boat was a 1979 24' Pantera
Approx weight dry was 4500 lbs
TRS drive

Also keep in mind the Headers mentioned above in the Ebay add above would exit really low on the transom & are primarily used in a jet boat application...

Which set would be a direct replacement for my motor with through hull exhaust (without silent choice)

I agree. Good advice.