ren3

This could be the dumb ass question of the weekend! I am retrofitting standard Lightning headers onto my twin 454s with TRS outdrives. My engines are not staggered. The engines had the cast iron Mercruiser chit manifolds on them. The engines are on 34" centerlines and despite my best planning it looks like the inboard headers are going to be interfering with one another even though the individual exhaust runners are slightly off set as you look at the inboard header on the starbord engine versus the inboard header on the port engine. I have to modify the center support on my engine hatches before I can tell for sure about the interference. I thought that the 34" centerline dimension was OK. If I indeed do have the problem that I think I do, is there a cost effective way to stagger one of my engines? I could move one forward about 7", but I do not know about an extension box or shaft for the velvet drive transmission. Is this even feasible. I have Hardin two piece valve covers so another set of headers that bend inward more than standard probably would not work either. Help would be appreciated, but keep the laughter down a little. The Hardin two piece valve covers on the right side in the picture are the ones that will be used. They are not the problem though. Thanks. Bob N.

DanB

Call Lightning in Lake Elsinore Calif and ask if there headers are any wider then stock cast manis, if so how much. Measure the clearence between your stockers and do the math.

formula31

Im running Gils on 33" centers, Not a great thing but there is still 1/4" between them.

GregP

I have Lightning headers on my Formula with TRS drives. Lightning makes two different width headers. I have the narrower set that is good for 33" centers, and with my motors being on 35" centers have lots of room between them. I had a set also on my Donzi with 33" centers and they cleared fine once installed. You did have to install the second one by removing the alternator and sliding it in from the front, as once the first one was bolted to the head you couldn't drop the second one in from the top.

On the Formula headers we did go several rounds getting them to hit the original exhaust locations (the Donzi set were right on first time). Never did get it quite the way I had planned, I wanted to match the way my old GIL's went all the way through the transom with floating tips. I think the reason is there are two different trans lengths with TRS, and when I gave them the vertical locations for my transom ports they used one trans length (shorter) and I have the other (longer), so they missed and I had to send the tailpipes back to be modified. The second pass was close but not quite. They offered to mod them again but I didn't want to loose all the shipping time so changed to transom mounted tips and hooked them up that way.

I ordered my headers through CP. If I did it again I'd do it direct as not all of the original measurement data I sent got transfered to Lightning. Also, my problem was compounded by having them make extra long collectors so the water would dump into the exhaust stream just ahead of the transom. A more normal length collector design with a length of hose to connect to the tips would be easier to line up and gives a little flexibility. In my setup the collectors end less than 1" ahead of the inside end of the transom tips.

The Lightnings are much better for plug access than the GIL's were, but I will have to talk to them about some exterior rusting where they didn't get the powercoat in between the tubes.


-Greg

ren3

Thanks for the advice. I spoke with Lightning today and they will make a set of inboard headers to solve my problem for $1850. Not a bad solution, and they were very helpful and understanding.

kingsize

Hey ren3.... does this mean you have a extra set of headers that you may want to sell ? Let me know if you do. my e-mail is [email protected].