not sure if my last post i did right or not but i'll do it again. first let me say hey to all. i am new to the site and have a couple cam questions. I have a 1977 3/4 ton hiboy with a 390 that we are rebuilding. i would like to find a cam that has good bottom end but sounds rough when it idles. i know from building shevys over the years (sorry) that short duration big lift built bottom end but duration is where a lot of your sound comes from. i notice that the majority of the people here seem to be crane fans and i am not because of a bad experience i had with them, but to each his own. Personal preference i guess. any how i was looking at the comp cams 270H which has a rough idle but is kinda high in the RPM range starting at 1800. and i also know from pers. experience that they are conservativly rated low. i stumbled on to a lunati grind # 00054LK. Specs are 230/230 @.050 and 554/554 lift. Rpm range is 1500-5000 and has a mild rough idle lobe sep is 109 and summit says it builds super low to midrange torque. What do you guys think of this and about lunati cams. $149.00 for cam and lifters at summit!!!! BTW i have also seen a lot of talk about using 360 pistons in a 390 and let me tell you from personal experience that you can. We have used a sterling # STL-H395P60 which is a 360 flattop with 4 reliefs, hyper and the best part is they are only $9 apiece at summit. Federal mogul says in a 390 with 71cc heads they will make 9.8:1. Not to shabby Ehhhh? Let me know what you guys think. Thanks.

 

I have a 265/276 comp cam 4x4 extrem with 110 center line, in a 351m it thumps. It starts at idle and goes to 5500. Alot of bottomend.

 

anything in the .494 to .550 lift range will give you the sound you
want without sacrifing bottom end. Headers also add to this lumpy sound as well.

 

Thanks for the reply fellas. Has anyone had any experience with lunati cams and how big can you go with stock springs and retainers?

 

It's not so much the retainers as it is the rocker shaft stands. They're made out of aluminum and they break easily with a big cam. .533" seems to be the most valve lift people around here are comfortable running. Whenever you get a higher performance cam you should get the recommended springs. I never say to use old springs, since I cannot be certain of what shape they're in, and they may float the valve.

 

thanks rusty70f100. Is there an aftermarket stand you can get that wont break the bank?

 

Yes. www.dscmotorsport.com. They're the steel stands. They are $240 for a set.

 

Whether or not you can use 360 pistons will depend on the pin height ( you don't want the piston too far down the hole at TDC or sticking up above the deck)and the skirt design ( if it'll clear the crank on a 390)

 

On my 390 the stock rocker shafts broke before the stands. The shafts are the weak link. You can either get end stands or get hardened shafts for $140. I bought the Dove stands as well. With stock unported heads I would recommend a dual pattern cam like the Crane 343801. Lunati makes a great cam and from what I hear they have hired on an FE expert. Their selection in the future might be the best in the business.

 

I would agree also with Ratsmoker, the dual pattern or dual duration cam is a good choice.
The slightly higher lift and durration on the exhaust lobe provides good exhaust scavenging
of all the exhaust from the combustion stroke. my added 2bits

 

I would have to agree with the dual pattern cam. I have a Comp Cams camshaft, 255/265 duration with .469 intake lift and .495 exhaust lift. With the 4 bbl carb I'm going to put on there, Desktop Dyno is estimating over 400 ft/lbs of torque up to 4000 rpm. It ain't a huge HP gain though, puts it at about 318 HP @ 4500 rpm. This is also with stock exhaust manifolds and dual glasspacks. with headers, it shoots the results up to 365 HP @ 4500 and 467 ft/lbs @ 2500 rpm. Also with stock non adjustable rockerarms, though sometime in the future they're getting ditched for some rollers from Oregon Camshaft.