cam advise for 454 mag
 

I know, yes it's another nagging cam question looking for advice. I want to put a very aggressive and noticeable cam in a pair of 454 mag motors in my 35 fountain. The motors are true 365 HP mag Motors with 200 hours on them. I will be adding a Holley 750 carb on a Victor jr. Single-plane intake. The heads are the large Square port and will be cleaned up in the bowl area. I'm looking for a cam in the 2000-6000 RPM range. I do have Gil exhaust manifolds and dry to the transom tips where the water and exhaust meet so I hope reversion should not be a problem. I do want to use a hydraulic flat tappet cam with less than .600 lift and a pretty aggressive duration. Would a 110 lobe center be too tight for a marine application?

I do like the Comp 4X4 Cam 11-243-4 cam which is 234/244 @.050 with .564/.570 lift on a 111 lobe center

The boat will not be raced and I'm not looking for huge numbers, I just want a good aggressive sound that will work with my application.

I forgot to add the blocks are standard bore with four bolt Mains and a steel crank again it only has 200 hours on each engine and I want to leave the stock pistons and compression. Thanks!

Why not a roller? I worry about flat tappets with low zinc oils. If you go for the performance the sound will come with your cam choice.

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[ATTACH=CONFIG]565339[/ATTACH]

I'm not using a roller just because of cost I have a limited budget. I use the Valvoline racing oil which has the highs zinc content

Let me clarify I'm not putting the cams in just for the sound I want a workable setup if I wanted just the noise I would put one of those stupid thumpr cams in and call it good

^^^^this.your initial investment with a hyd roller is higher but imo it is the way to go.you might think about a 168731 crane hyd roller.a 750 carb is great for a small block but with a good exhaust and the right cam a 850 would be a better choice for your 454.if buying a carb new the 850 is a no brainer.

if a hyd roller is not in the budget and you absolutly can,t swing it their are some good hyd flat tappet cams but i have no idea on what one would work for you,i have not used a hyd flat tappet cam in a boat for a long time.

Heres a buddys 454's. Started life as 370's, basically, a 454 Mag. Boat ran upper 50's back when engines were stock. Runs 63-65 now. Rectangle port GM heads, Single Plane Proffessional products "hurricane" intakes, 850 quick fuel marine carbs, stellings headers, roller rockers, and a crane 134561 cam. 236/246 114 LSA, 551/571 lift. Flat tappet. one of the engines expired 4-5 years ago, due to a leaking riser on the stock 454 mag iron exhaust manifolds. Mike Tkach redid that engine for him. The other engine, has been going strong for the last 15 years or so. Believe it or not, they did NOT revert water with those cams, and stock exhaust. But, he got a good deal on the stellings, and put them on. The engine that was recently rebuild, recieved the crower cam saver lifters, that have the groove cut in them. The other engine, still has the standard flat tappets. Boat has close to 2000 hours on it, and has never had a cam lobe or lifter failure. He beats the chit out of this boat, and engines, and they just keep running!

https://www.youtube.com/watch?v=3LriYY1QCtU

https://www.youtube.com/watch?v=X7olqjFN8p8

I'd prob run a cam like the old Mercruiser 440HP 454 "cyclone" engine. This cam is very close in specs to it. 233/241 110 LSA, 106 ICL. Assuming you will be running aftermarket exhaust, and decent length risers, or fully jacketed risers.

https://www.summitracing.com/parts/lun-10110704

that was the last marine engine i installed a hyd flat tappet cam in,glad to hear it is still flying around.

Mild Thunder thank you for the video! I'm just going to use the hydraulic flat tappet cam for now and when I go for a complete overhaul I will do the roller set up. With only 200 hours on the motors I would like to use this up first and then later go with a completely different setup along with the rollers.

Lunati cam looks like a good option but I wonder if the 110 lobe separation might cause too much overlap and potentially suck water in even though I have dry exhaust water still can get into the exhaust because the way the fountains sit there azz in the water

I'm probably going with this package for my Merc 420 rebuilds.
https://www.summitracing.com/parts/c...FQS4wAod_I4ETQ
https://www.summitracing.com/parts/c...FQe1wAodxOkO1g

I am leaning towards a lunati voodoo cam number 60204. 233/241 @.50 and .554/.572 lift on a 110 LSA

My question, would the 110 lobe Center be too tight and cause too much overlap in a marine engine with dry to the tip Gil exhaust. My risers are approximately 22 inches long as the motors set way back against the stern wall of the boat.

Thats the same cam i posted, the 60204 is the old part number i believe.

Its not the LSA thats an issue, its the overlap.

When you say "dry to the tip" , do you mean dry THRU the transom, or dry TO the transom mounted tip? Some guys think dry means, its dry to the actual tip thats screwed on to the transom, and a rubber coupler is used to connect riser to tip. That is not dry/fully jacketed exhaust

My risers are approximately 14 inches to the transom tips the inner stainless steel pipe of the riser carrying the dry exhaust ends at the tips that pass through the transom. so the tips is where the exhaust and water meet!

I love the specs on the lunati I guess im worried about water due to the overlap. There are quite a few post on YouTube of this cam and it sounds fantastic and everyone is very happy with power range

I am thinking I am going to pull the trigger on this Comp 4X4 Cam 11-243-4 cam which is 234/244 @.050 with .564/.570 lift on a 111 lobe center. I really like the numbers that MILD THUNDER suggested on the Lunati cam, however, since I do not have true "dry exhaust" I am afraid of the 110 lobe center with a 233/241 duration. Please chime in and I will leave everyone alone after that....Ha Ha!

I've posted this many times. Tighter LSA's, don't always mean the camshaft has MORE overlap.

Your 234/244 111 LSA cam, will have more overlap, than the 233/241 110 LSA cam.

At .006, the Lunati cam is 276/284. At .050, its 233/241. Your comp cam, is 278/288, and 234/244. The comp cam , will have roughly 2 degrees more overlap at .050, and 2-3 degrees at .006. I don't have the cam cards for exact numbers, but that should be close.

Cam for cam, going to a narrower LSA closes exhaust later, thus longer after TDC. More'suction' on the exhaust from the piston.

Better words: longer amt of time that the piston is going down while the exhaust valve is still open.

Thanks mild Thunder I am trying to listen. Please correct me if I'm wrong but A good rule of thumb @ .006 staying under six degrees of overlap should keep you fairly safe correct?

Slight correction:

A good rule of thumb @ .050 staying under six - 8 degrees of overlap should keep you fairly safe correct with good wet exhaust...this is what Crane has preached.

Sorry Had It reversed thank you

I ran the livin dog chit out of those 561's MT mentioned. Never any issues. Those cams in a 454 run well especially with some aftermarket good flowing heads. I ran with Jim v assisted dart 265 oval port heads, torker two dual plane intakes and 9022s. Good running combo at a conservative 480 hp. I'd run again in a heartbeat but not without zinc additive.

Yes and no. As stated earlier, the crane 134561 236/246 114, ran just fine in my buddys 454's , with stock cast iron center rise exhaust. For many years. That cam had 13* of overlap at .050 .

I ran the 741 roller, that had 16* of overlap at .050, with stainless marine manifolds, that had short bravo risers, that coupled to the tips just like yours does, with no reversion issues.

Mercurys 525 EFI engines cam, had 12* of overlap at .050. They ran wet exhaust with silent choice diverters.

All that overlap talk, but heres another option. Find a friend or someone local who can Tig Stainless. Get your hands on some stainless pipe, and have them extend your current risers, to go all the way thru the transom, and eliminate the screw on tips/rubber coupling. If you find its too loud, you can install some Gibson turn downs, some clamp on bullet mufflers, some switcheable air activated mufflers, or some drew marine shotgun tips, or , many other options, and run the cam the engine will like.

Yes, many have used the Stainless Marine and the 741 . Good point.

Joe you ran 741 in 454 NA? Or what that in your SC builds.

Thanks everyone for all your input and help!