I've got some extra fun money and have been throwing around the idea of a set of Lightning headers for my new motor. I'm looking at the standard option, stainless inners and reg steel outers since I boat in freshwater.

I've been doing some research and it seems they provide a nice increase over stock merc manifolds but what about if you allready have aftermarket HP manifolds and long risers?

Currently have Glenwood Marine HP manifolds and FastGlass 4" smooth long risers thru hull. I have had these since 1992 and they are still in excellent condition. I have no doubts they flow very well as I was running 73-77gps depending on load and air temps in a previous 355 solid roller.

I just don't want to blow $2K on 1-2 mph.


Motor Specs....
1980-85 4 bolt bored .030", align honed, decked .020"
Forged rotating assembly, Eagle 4340 crank, I beams w ARP 2000, Speedpro forged L2304 pistons w .100 dome. Setup is balanced very well.

224/230 .537/.511 112LSA 110ICL
Morel Retro Hyd Roller lifters
McQuillen Racing prepped AFR 190cc heads 2.02I 1.60E milled 74cc puts SCR @ 10.0-1 and DCR 7.8-1
Performer RPM, Crane 1.6 widebody roller rockers on intake and Lunati 1.52 widebodys on exhaust,
FluidDamper harmonic balancer
Smith Bros .80 wall pushrods
Holley 750 4150 DP
ARP everything
MSD ignition
Glenwood HP manifolds and 4" FastGlass Stainless long risers

I went from stainless marine to lightnings. I didn't notice any speed increase, but it sure sounded faster. They look better too.