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Which camshafts to use in 1983 crusader 454xl 350's

Jeff0101

Member
I pulled the motors out of my chris craft tournament. They where still running strong but the port was leaking some oil and the starboard had a lifter tick so I'm in the process of getting ready to send them out to the machine shop to have them cleaned up.
I was hoping to get some advice on which cams I could recommend to the shop. I'm not interested in trying that any performance gains but I'm guessing there there are options that would keep the same performance but have better efficiency if not does anyone know the replacement part #s.
I thought I would ask here because it seems most aftermarket stuff is focused on high rpm or high horsepower motors.
 
I pulled the motors out of my chris craft tournament. They where still running strong but the port was leaking some oil and the starboard had a lifter tick so I'm in the process of getting ready to send them out to the machine shop to have them cleaned up.
I was hoping to get some advice on which cams I could recommend to the shop. I'm not interested in trying that any performance gains but I'm guessing there there are options that would keep the same performance but have better efficiency if not does anyone know the replacement part #s.
I thought I would ask here because it seems most aftermarket stuff is focused on high rpm or high horsepower engines.

Not necessarily in the Marine world.
Why not contact a reputable camshaft company, and ask your question of a reputable sales person?

I would suggest that you steer clear of any automotive engine advice..... no matter how well intended!
 
The factory cam is really hard to beat in terms of performance vs efficiency.....It's a standard grind and you can get it for either rotation. There is another cam that has a bit fatter set of lobes that Mercruiser used but the cruise efficiency is worse than the standard factory grind.
 
Thanks that's what I was thinking. I know the shop I'm going to deals primarily in vehicle motors and I just want to make sure I keep it right.
Do you know where I can find the stock #s. I havnt brought the motors to the shop yet. I'm still tearing them down and getting them ready.
I was going to call summit and talk to them but if I can find the stock cam #s I can just order them or pass the info the the machine shop.
 
I was going to call summit and talk to them but

Ayuh,..... Call the Cam Company,........ not their retailer,.......

All the better cam companies have tech lines you can call, or email,......
 
............ I know the shop I'm going to deals primarily in vehicle engines and I just want to make sure I keep it right.

The cleaning and prep, the machining process, the fitment and assembly, etc will be very similar (if not the same) between the auto engine and the marine engine.
Parts/components selections are where they need to have true Marine Engine building experience.

You may need to become pro-active in that you get very involved in the parts selections.

I would suggest that during the assembly:
..... have the Tech perform a PPS (positive piston stop) procedure, as to verify true TDC between the harmonic balancer slot and the timing chain cover tab markings.
or
..... use new indexed balancers and verify via PPS.
or
..... have them index your existing balancers from ZERO up to 35*, and again verify via PPS.


.

 
Just be sure that the cam you use is designed for marine use. Automotive cams (particularly if designed to improve performance) will have overlaps between the closing of the exhaust valve and opening of the intake valve. It gives better breathing and performance at high rpms, but the overlap can cause a brief suck back of the exhaust gas into the cylinder at low rpms. Not a problem in autos but in boats this can bring back to the engine some of the coolant water (often salt water) that has been put into the exhaust stream at the elbows. This corrodes the valves and generally is not good. It is a mistake that that well meaning automotive engine builders can make when tryiing to improve the performance of a boat. You want the smooth idle and the ability to put out steady power for long stretches that comes with a good marine design. Marine cams are made the way they are for good reasons.
 
John is correct, and is why you will want to consult with a Marine Engine camshaft expert.

For the Marine build, the LSA (lobe separation angle) will be near 112* in camshaft angle.
If we exceed this, and while at low engine speed, it may cause enough exhaust gas reversion that may cause water to be pulled into a cylinder, as John explained.

This is right from Dennis Moore:

To make it a little easier for you. For a big block Chevy you would want a lobe separation angle of no less than 110 on a camshaft that has up to 224 degrees of intake duration and 230-234 degrees of exhaust duration. Anything with more duration would require a 112 degree LSA. The tighter the LSA (no tighter than 110) the better the engine will perform in a marine application (at the cost of some water reversion). This is pretty much agreed upon by camshaft manufacturers and a general rule of thumb.
Sincerely
Dennis Moore
FAMILY AND PERFORMANCE BOATING MAGAZINE
.
 
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