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View Full Version : 4.3 performance exhaust ??



8-ball
03-05-2007, 12:10 PM
Gentlemen, Anyone know of an aftermarket performance exhaust setup to replace my stock 1997 mercruiser 4.3L exhaust ? Much improvement gain over stock ???? reasonably priced ??? ----- will ultimately go V8 when the "6 pack" gives up the ghost. ---- am presently installing 4 bbl. on performer intake and may want to go one step further with the exhaust to comliment the 4 bbl. setup. This all going on Donzi sweet 16. Input appreciated. Thanx and may the "Spring Gods" smile early this year !!!!! Thanks - Bob L.

Newby
03-05-2007, 12:23 PM
I changed my stock Mercruiser exhaust to GLM Aluminum manifolds and risers. I do not know if they would be considered performance enhancing, but they are considerably lighter. I am still dialing my setup in after some substantial engine work, including a valve job and head gasket etc. I expect the boat to run a little better, but don't know how much yet.

Newby
03-05-2007, 12:54 PM
I changed my stock Mercruiser exhaust to GLM Aluminum manifolds and risers. I do not know if they would be considered performance enhancing, but they are considerably lighter. I am still dialing my setup in after some substantial engine work, including a valve job and head gasket etc. I expect the boat to run a little better, but don't know how much yet.


Here is the link: http://www.mooreperformance.org/index.html

The Hedgehog
03-05-2007, 02:18 PM
Imco Thumpers are the way to go on a V-6. I have some picks posted around here somewhere. You can get them with the polished alum riser.

I don't know if you will see much pickup. I put them on my 2 bbl but was hampered too much by the restrictive 2 bbl. Much lighter than the iron. I am sure that the 4bbl needs to breath better on the exhaust side.

This winter we put on a performer roller cam/manifold combo with a 4 bbl. Also ported/polished the heads and put in bigger exhaust valves (Inconnel). We are thinking we will hit somewhere around 250-260 hp or so. The engine is going back in this week so I will post the results.

Getting it ready for next year. We plan to take the V-6 up to 400+ hp with a centrifigal blower. Then it will be time to light the fuse and stand back!