454 cam upgrade questions/opinions..
#12
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If you go with a bigger flat tappet cam, you will push your peak torque and hp into higher rpm ranges and loose lower end torque. The stock cam is good to 5400rpms. You won't gain more than about 15-20hp with bigger flat tappet cam and the only gain will be at WOT. 30-40hp is possible with a roller cam.
I gained about 150 rpm switching from the same cam in my 525SC to a Crane 731 roller.
I gained about 150 rpm switching from the same cam in my 525SC to a Crane 731 roller.
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The boat planes great as of now, what do you think the low end loss might be? I may be able to lose some, but I don't want to make a mistake either..
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You can experiment with more cam if you want...it's your choice, but if you're not willing to go with at least a hydraulic roller cam, then the stock Merc 420hp flat tappet hydraulic cam is already a lot of cam for a 454. This is especially true in light of the dual plane intake manifold and the exhaust system you're running, but who knows....you just might get lucky with a larger flat tappet cam. Of course I'm always chanting about a well breathing exhaust system....and so, the first thing I would do is upgrade to a better breathing aftermarket exhaust like Stainless Marine or something comparable. Just my .02....hope it works out for you.
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You can experiment with more cam if you want...it's your choice, but if you're not willing to go with at least a hydraulic roller cam, then the stock Merc 420hp flat tappet hydraulic cam is already a lot of cam for a 454. This is especially true in light of the dual plane intake manifold and the exhaust system you're running, but who knows....you just might get lucky with a larger flat tappet cam. Of course I'm always chanting about a well breathing exhaust system....and so, the first thing I would do is upgrade to a better breathing aftermarket exhaust like Stainless Marine or something comparable. Just my .02....hope it works out for you.
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OK, I got a nice exhaust now... stock 496 stuff, everyone has said it will support my engines power easily, I just realized that since I spun a bearing the particles must have went through the lifters too... I forgot about that, so now I will for sure be buying a new cam and lifter set.
Here is the deal, the stock 420 cam that I have now is expensive, 290.00 for cam and lifters.
I have found a few from summit that are 226 intake duration in stead of the 228 that the 420 cam is, should I worry about 2 degrees duration smaller?
Now I am open for cam grind suggestions, roller is still not an option this year, exhaust is not a problem now either, any help would be great!
Here is the deal, the stock 420 cam that I have now is expensive, 290.00 for cam and lifters.
I have found a few from summit that are 226 intake duration in stead of the 228 that the 420 cam is, should I worry about 2 degrees duration smaller?
Now I am open for cam grind suggestions, roller is still not an option this year, exhaust is not a problem now either, any help would be great!
#19
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I am rebuilding my 400HP 454's this winter, I have a set of Merlin heads to go on, with a small runner single plane intake,9.0:1 compression, and 454 CI.
I want to try to get the most I can from them, my 400/420 cam is decent but would a cam change be worth it? what cam have guys been running with a combo like this? I am not looking to go roller at this time, not in the budget this year, any suggections would be great, thanks..
I want to try to get the most I can from them, my 400/420 cam is decent but would a cam change be worth it? what cam have guys been running with a combo like this? I am not looking to go roller at this time, not in the budget this year, any suggections would be great, thanks..
Lobe seperation is 112 and duration at .050 is 229/229 with the hydraulic roller lifters.
I also have a 1998 454 Mag set of heads just rebuilt Ported as far as i would take them. 2.25/1.94 Valves and new springs just freshened. let me know if there is interest.
Bob
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I have a Crower custom grind in great shape. lift is 561/561 with a 1.7 rocker 594 with a 1.8.
Lobe seperation is 112 and duration at .050 is 229/229 with the hydraulic roller lifters.
I also have a 1998 454 Mag set of heads just rebuilt Ported as far as i would take them. 2.25/1.94 Valves and new springs just freshened. let me know if there is interest.
Bob
Lobe seperation is 112 and duration at .050 is 229/229 with the hydraulic roller lifters.
I also have a 1998 454 Mag set of heads just rebuilt Ported as far as i would take them. 2.25/1.94 Valves and new springs just freshened. let me know if there is interest.
Bob