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Originally Posted by demax990
(Post 4260402)
maybe a set of 1.8 rockers would help? I know jd has a set for sale in swap shop
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Just so we get the cams basics down, here's a quote from me in another forum:
Mercruiser BBC Flat Tappet Cams Standard Flat Tappet (oval heads) Merc#431-4734 / GM#3904359 .004” 287*, 302 .006” 278*, 289 .050” 214*, 218* .200” 111*, 119* Valve lift with 1.7 .460” , .480” ICL 110 ATDC ECL 118 BTDC 114 LSA Mag BBC 454/502 Flat Tappet (rect heads) .004” 296*, 296* .006” 286*, 286* .050” 224*, 224* .200” 130*, 130* Valve lift with 1.7 .510”, .510” LSA 115.5 Merc Part#431-9830 / GM#14096209 ICL 114 ATDC ECL 117 BTDC GM Part#10185060 (same as above but ground with 5 degrees advance) ICL 109 ATDC ECL 122 BTDC Merc Std BB Roller Merc# 431-850453T / GM#12552296 .004” 280,299 .006” 266*/284* .050” 204*/209* .200” 113*/114* Lift .480”/. 483” ICL 115.5* ECL 120.5 LSA 118* ……………… Merc Mag Roller Merc# 431-850478 / GM#12551622 .004 300*/ 300* .006 288*/288* .050” 225*/225* .200” 125*/125* Lift .483”/. 483” ICL 109* LSA 115.5* |
I don't know a lot about cams but what are you trying to tell me :party-smiley-004:
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the first two are the 330-365 mag flat tappet cams followed by the 310 and 454 mag post 94 or 5 roller which i think is still rated 365 hp. they got very conservative on the lift on the later mag roller cam. the 454 HO is a crate engine rated 425 HP at the crank. that cam has a good bit more lift, similar duration and a 112 lobe sep angle. it is a bit much cam for peanut heads but it will do just fine and be in the ballpark when you upgrade to rectangle or aftermarket alum heads. with the Gil exhausts there are no real reversion issues with that cam. apparently you have to watch valve to piston clearance with those pistons. the valve relief is not real deep. and will be even more important to watch with the 2.18 or 2.25 (or 2.3?) valves in the next set of heads.
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I want to run a bob m cam with a set of aluminum heads maybe and my short block but I might just run this set up for the next 2 seasons. I want to use my moral lifters and comp roller rockers but that means a roller cam. I like the looks of the 454 ho cam but you think it will be overkill?
Also I just want to say thanks to everyone on oso this one of the most knowledgeable and helpful forums I have ever been on |
Originally Posted by demax990
(Post 4260451)
I don't know a lot about cams but what are you trying to tell me :party-smiley-004:
Originally Posted by demax990
(Post 4260475)
Also I just want to say thanks to everyone on oso this one of the most knowledgeable and helpful forums I have ever been on
Teddy Peanut Butter (made in Everett, MA) is amongst the best. |
And never refer to merc published cam specs .if your eyeballs are on the numbers on the back of a oe roller because its in your hand go to the gm crate spec for the mag and vortec .but that majic flat tappet that adds 100 horses to the wagon motor , thats something something there .
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I would consider finding someone with a good takeout Mag roller cam and buy it from them to run with your peanut port heads. I think Mike Tkach on this forum had a couple for sale recently. You could probably find one for less than $150. You can run your Morel lifters with this cam no problem. You may or may not have to run a custom length pushrod to get your valvetrain geomoetry set up correctly. Pretty sure with such a moderate lift you could wing it with the Mag roller and run the stock length pushrods and even the stock rocker arms. If you had a Gen VI instead of Gen V it would be a simple matter of running the stock roller lifters and dog bone retainers, and store away your Morel's for when you order up that monster cam from Bob.
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Originally Posted by ezstriper
(Post 4260144)
I would not worry about forged crank and rods for a 500hp engine, put forged pistons in and some decent iron heads..it will be fine...we have raced(with no failures) cast crank, 3/8 rods, 2 bolt main engines that ran great for many many passes...put that $$$ towards heads..and if its a genIV I would look at the large ovals like 781's make a great marine setup, use a performer RPM intake and decent cam Roll on..
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so do you guy think that the 454ho cam will have to much lift for the peanut ports? or would I be better off with the mag roller installed at .050”. if I am not mistaken I want to keep the duration under 235 and lsa no more than 112.
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