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gcarter
05-23-2007, 07:05 PM
The new (to me) '88 Testarossa, as I purchased it, has a pretty radical cam that would probably be better suited to drag racing rather than a boat.
Additionally, it also came w/a nice set of Gil exhaust manifolds and LOOOOOONG risers and tail pipes that extend all the way through the transom. These tail pipes are water jacketed, but the exhaust is dry all the way to the end. See the 1st pic.
I have purchased a Comp cam #11-240-4, see spread sheet for card info.

Camshaft Specification Table
Part Number 11-240-4
Engine 1965-1996 Chevrolet
396ci-454ci
8cyl.
Grind Number CB XM 278H-12
Description


Intake Exhaust
Valve Adjustment 0 0
Gross Valve Lift 0.564 0.567
Duration At 0.006 Tappet Lift 278 292


Valve Timing At 0.006
Open Close
Intake 29 69
Exhaust 80 32


These Specs Are For The Cam Installed At 110 Intake CL
Intake Exhaust
Duration At 0.05 234 244
Lobe Lift 0.332 0.334
Lobe Separation 112


Recommended Valve Springs 924-16



My desire is to remove the dry risers, replace them w/shorter wet risers so some sort of switchable exhaust can be installed. See pic 2.
My question is;
Can the new Comp cam be safely used with wet exhaust? Or should a different cam be used to accomplish the exhaust switch?????
I already have received some advice that the risers are too short to prevent reversion.
Thanks in advance

mrfixxall
05-23-2007, 07:34 PM
George,nice Cam But I Think It Will Sound Like The Cam That Is In The Boat Now,,the Xm270h-12 Is A Vary Nice Cam For A Big Block,,vary Vary Strong Midrange...starts Pulling Hard At 2800 Rpm Where The Xm278 Starts Pulling At 3500 Rpm..and In Reguards To Your Risers,,you Can Cut Yours To Fit Then Have The Ends Welded,1/2 '' Bead At 12 ,3,6,9 Oclock And The Water Will Blow Out The End..

gcarter
05-23-2007, 08:05 PM
George,nice Cam But I Think It Will Sound Like The Cam That Is In The Boat Now,,the Xm270h-12 Is A Vary Nice Cam For A Big Block,,vary Vary Strong Midrange...starts Pulling Hard At 2800 Rpm Where The Xm278 Starts Pulling At 3500 Rpm..and In Reguards To Your Risers,,you Can Cut Yours To Fit Then Have The Ends Welded,1/2 '' Bead At 12 ,3,6,9 Oclock And The Water Will Blow Out The End..
I appreciate the cam reccomendation, what I want is a cam that will work with much shorter and flatter risers, switchable exhaust and give really good performance.
Elaine put up w/the Minx for 2 1/2 years and was a pretty good sport about it. With the new boat, I think it's really impotatnt to have the concession of "part time quiet".

BUIZILLA
05-23-2007, 08:09 PM
XM270 is a good safe choice...