New exhuast

[dexman38]

What is your oppion on the headers for the 496 motor, they sayyou gain 60 hp. does anyone have them ,if so what kind of speed did you gain.

[Jyruiz]

I would like to know as well, who makes them?

[bfab33]

CMI $3,600.00 www.custommarine.com

[dexman38]

what kind of speed will you get for that 3600.00

[Kilrtoy]

Just buy a new motor dex and call it a day...
You can pick up a 500 or 525 and have it installed for around 15K and pick up over 10MPH..
The headers might I say MIGHT give you 1 MPH

[bfab33]

maybe 1
MPH

[dexman38]

new motor ? x-mas ?

[Raylar]

Good headers like CMI's long four tube (sportsman) or Bassetts tri-y will add about 30-40HP over stock un-molested Merc stock 496 exhausts. Raylar has had all of them and other manifolds on 496's stock and otherwise for years on our dyno pulls. Take the turbulator plates out of your stock 496 merc manifolds and you will gain about 12-15HP and about 1 mph. the CMI's should give you about 3-4 mph and thats what most who have tried them so far report at best. Please realize that the new CMI 496 kit headers for $3600 come unpolished in satin stainless with brackets and accessories to remount oil filter ECM plates etc, and bravo tips. The polished versions will set you back about $4500. Also, I understand the CMI's for the 496 are about 1" taller than stock 496 risers and in some boats with low hatch clearance that may be a problem. Solution here, get informed, ask a lot of questions, make sure the selling company will verify the fit in your hull and don't believe everything you read!
Ray @ Raylar

[HotDogz]

Picked up 300 rpm with Bassetts TT tri-Y waterjackets...

[bigq]

Lightning headers are well made and I believe a fraction of the cost of CMI. just have know idea how big the fraction is. :D

[Beer-30]

I noticed CP has a Lightning Header set for 8.1L. Since people are looking for info here - has anyone put any on?
http://www.cpperformance.com/images/310-4030.JPG
Exhaust Header System
310-40308
Engine Application: Chevy - Big Block
Brand Name: Lightning Marine
Standard Jacketed Header - 496 8.1L Mercury Standard Application
These headers are designed to be a replacement for Mercury, OMC or jet manifolds. However, they terminate approximately 8" aft of stock manifolds and are projected to meet the exhaust tips providing they are in the stock location. Headers will have about 1/2" clearance between header and tall Moroso valve covers. Headers come complete with bolts, gaskets, water fittings, pet cocks, etc. (less 4" hose and 4" hose clamps). Factory oil filter requires relocation.
ALL THIS PLUS THE BEST 2-YEAR WARRANTY IN THE INDUSTRY
Through continuing research Lightning Mfg. has developed a Dual Porcelain Coating that resists the harshest of salt water environments. Now as an option they are able to apply the same high tech coating to a 316L stainless steel lined header once thought to be the cracking alloy and render it crack resistant.
Sale Price $2,040.00 $1,949.99
(Savings: $90.01)