magnum camshaft and spring lift

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Muscley MOPAR

Muscley MOPAR

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i plan on putting a 5.2 cam and 1.7 rockers in my 5.9 magnum block the 5.2 has lift of .432 nd 5.9 .410. my question is what can i get away with, with stock heads/valves springs whats the max lift the spring will take i think that i should be fine with the 5.2 cam and 1.7's but i know alot of people say the stock springs dont have much room for extra lift
 
I have only measured 1 set of magnum heads and they would handle about .475 lift. Due to manufacturing tolerances not all heads will measure the same but I'd be surprised if .432 would be a problem. In reality your best bet is not to ask opinions but to actually measure what your particular engine will handle.
 
With adding the rocker ratio anyway: speeds up the hit ,at the valve,need stable valvetrain. Hughes 1110 springs,maiching retainers sweet to .510 lift..
 
Right now in my driveway is my dakota, 99' 5.2 with 1.7 harland sharp rr's...it runs great and those two things will really wake up your 360. I'm happy the 5.2 cam swap trick is finally getting around accurately:)
 
i also noticed that the 94-97 360 had a longer duration than the later 360 .264 in and .274 ex nd later .269 .249 and the 5.2 is .264 nd .250ex wouldnt the duration in the earlier 360 offset the perfromance of the 5.2's lift and ive looked at some specs for the springs and valves and as far as i can tell they should be able to handle high .400 lift http://dodgeram.org/tech/gas/specs/valve-5_2.htm
 
Springs and valves are only part of the equation. The reason for the lift limit is generally spring retainer to valve guide interference

I look at duration as determining the rpm range the engine will make peak power in and lift more or less determines the power it makes. There's more to it than that but those are the basics. With that in mind I'd wonder how the 360 could breath good with a shorter duration cam such as the 5.2's cam? If your really wanting more power and going through all the work to swap the cam why not have one reground to give you more duration and lift? Generally doesn't cost that much if you already have the cam core. The only thing you might run into is if they reduce the base circle it'll cause you to have to run slightly longer pushrods and you'd definitely need better springs than stock to take advantage of the stouter cam. The ones Bomber mentioned work good
 
Muscley MOPAR said:
i also noticed that the 94-97 360 had a longer duration than the later 360 .264 in and .274 ex nd later .269 .249 and the 5.2 is .264 nd .250ex wouldnt the duration in the earlier 360 offset the perfromance of the 5.2's lift and ive looked at some specs for the springs and valves and as far as i can tell they should be able to handle high .400 lift http://dodgeram.org/tech/gas/specs/valve-5_2.htm
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That's very interesting i wasn't aware of that. You have a good point, but then so does fishy. Comp i believe and bullet cams for sure will regrind you a nice setup for not alot of $ if that's an issue
 
fishy68 said:
Springs and valves are only part of the equation. The reason for the lift limit is generally spring retainer to valve guide interference
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Yes, you have to have your "head guy" make sure that there is enough lift in the heads. He should check how much room is between the valve guide/seal and the spring retainer, so they don't bottom out at max lift. In addition to making sure that your springs can handle it without getting into coil bind.
 
ya i was just kinda wondering what i could get away with im not looking for alot of power maby 300 or so out of little modifications for a trail truck (79 ramcharger) i toyed with the idea of putting a decent cam in but then id wann put in springs and get the ecu tuned im basically keeping myself in limits
 
If I'm not mistaken the 300 HP crate engine uses about that same size cam so 300 out of yours should be no problem. Of course you have to have everything else in top condition and in tune. What do you mean "get the ECU tuned" in a 79 trail blazer? They weren't computer controlled. Did you swap over everything from a newer truck?
 
ha ya sorry wasnt very clear about that... im in the process of putting the whole fuel injected ecu harness and all setup from a 97 ram 1500 into my ramcharger and i didnt want to get so out of control that i get out of my stock tune...im not looking for a mean SOB just a noticable upgrade from the 245 stock motor and not to mention the 150hp 318 haha, just better starting, performance, and fuel econmy
 
Muscley MOPAR said:
ha ya sorry wasnt very clear about that... im in the process of putting the whole fuel injected ecu harness and all setup from a 97 ram 1500 into my ramcharger and i didnt want to get so out of control that i get out of my stock tune...im not looking for a mean SOB just a noticable upgrade from the 245 stock motor and not to mention the 150hp 318 haha, just better starting, performance, and fuel econmy
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Gotcha...
 
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