"http://www.lunatipower.com/Product.aspx?id=2325&gid=297

This cam should work well with the parts you already have.

This cam will make more power but not be as street friendly.
http://www.lunatipower.com/Product.aspx?id=2326&gid=297"

parts i have right now. are listed below, trying to give all the info for the best advice
-1 piece rr seal non roller 350 4bolt .060 over
-silvalite flat top pistons
-gm vortec heads, ported/polished and bowl blended
-performance valves with the bee hive springs for higher lift
-electric water pump
-double roller timing chain
-world products cross winds intake(was told i should get the rpm air gap..?)
-edlebrock 650 or Holley 750(have both) carburetor
-3:73 posi rear
-700r4 trans (have not selected stall yet)

this is intended to be a weekend driver but i don't want to be breaking things every time i floor it. want as much power as i can get while being able to jump in and drive and not have to worry about fixing it all the time. just had a cam guru tell me one of these would be the best cam selection for this build. just looking to confirm

thank you
brian

 

Have you accurately calculated your static compression ratio?
Is there an option for you to upgrade to a roller cam?

 

i have not figured out the compression. i think the piston site said with my heads i should be around 9.5 I'm not a gear head so i could be wrong but i seen that # on a few sites when i was looking for pistons.

roller cam, i could. i have not purchased the cam/lifters yet. but i don't have a roller block does that make a difference? i want as much as i can get out if this set up(streetable)

thanks

 

Without knowing the exact compression ratio it becomes difficult to spec a cam. Cam duration and the SCR go hand in hand.
If you want to do a little reading here's an excellent article.
http://www.empirenet.com/pkelley2/DynamicCR.html
I run a Vortec headed 350 with a 700R4. 3000 stall and a 3.70 rear gear.
I have a calculated compression ratio of 10:1 which is about the limit for an iron headed engine on pump gas with the cams that you've suggested.
I opted for a retro fit roller upgrade. It's a little pricey however I believe it's worth every dime.
My cam of choice is the Comp Cams XR276HR.
Very similar to your setup. With it I've run consistent 12.7's at 105 mph. 3700 lbs.
If I were to choose between the two cams you had listed, I'd go for the smaller one. Typically that results in a more enjoyable driver, producing more low end torque than the larger cam would.
Further to that, as the article demonstrates, longer duration cams need higher static compression so as to help build cylinder pressure prior to ignition. Your compression is probably in the low to mid 9's. I say probably. With lower compression, a cam with less duration is desirable.
If it's at all possible, can you get a history on the short block? Has it been decked? Do you have piston part numbers? What head gasket is being used?

 

very good and helpful info skinny, thank you. you toched on something i probably should have mentioned as far as desire goes. i would rather have get up and go then be able to 150mph. the short block is fresh from the machine shop. i didnt have the work done bought it off a guy who did. i dont think it's been decked, head gasket... i was just going to use a standard felpro type gasket.. should i consider something els? i'm not strapped for $ but i dont want to spend $ foolishly. pistons are sealed power 345NP60

 

Your engine is pretty much a copy of mine so based on that and we ASSUME a few things:
Vortec chamber volume. 64cc ( possibly less)
Piston deck height. Stock is .025"+ below deck.
Piston valve relief volume. 5cc
4.06 bore x 3.48 stroke.
.039" compressed gasket thickness.
SCR works out to 9.92:1.
That's getting up there.
Using the smaller of the two Lunati cams, with the cam installed straight (106 ICL) then the dynamic compression works out to slightly less than 8:1.
As far as specs go, that's not too bad.
As far as roller vs flat tappet. Roller is the way to go. You get more cam for your money with the same advertised duration because of the faster lift rates. There's also the added benefit of lower maintenance because the roller cam doesn't require the specialized engine oil additives that flat tappets cams do. Not to mention the lack of a required break-in period for the roller cam.

 

skinny wow thank you so much. i'm kinda new to wrenching(started a little late but having fun learning) and i love when i get to learn and understand new things. i really appreciate the info you shared. so you think i should to with the XR276HR cam you mentioned, roller rocker, and lifter? can i ask 1 more q with out sounding to stupid.... do i have to do anything as far as timing is concerned... i admit i get lost when i hear these guys talk about degreeing a cam and advancing or retarding it. i'm hoping i can just set it to tdc and be done.... ya im that green lol

 

Many cams are installed without degreeing them. I do it for the data. I like to be technical that way. (I also enjoy it.)
That being said, chances are you'll have no trouble just " lining up the dots " on the timing gears. One thing for sure is that you should be checking all the various clearences. Retainer ( at the guide, the spring and coil bind), piston to valve, etc.
I'm not neccesarily specing that cam for you. I've used it with success although I know there are others that will perform as well or perhaps even better. I still prefer roller. I had a flat tappet cam go flat on me. The expense of the rebuild certainly outpaced the cost of a roller setup. Still many others stay the flat tappet route.
One thing of note. I had been investigating different cams for use with the Vortec heads and came across an interesting perspective. Seems the stock Vortecs (I understand yours are polished and ported) don't flow well above .480" of lift. In fact, it's been said that flow actually decreases beyond that value and doesn't recover as the valve closes. As a remedy, cams with lift in the .480 range are spec'ed with duration suitable to the compression ratio and application.
Check out this thread. It's a long one but there are a few nuggets of useful info in it.
https://www.thirdgen.org/forums/engi...st-builds.html
Here's one of the cams suggested. I'm interested in it myself.
http://www.lunatipower.com/Product.aspx?id=2007&gid=281

 

thanks for the tips. so that one you just put on i looked at was that diagram saying it needed to be degreed? gosh i hate not knowing this stuff.

 

The diagram shown in the link(cam timing card) is the reference used if the cam IS degreed. This doesn't mean it HAS to be.
I'd be willing to bet that a large number of these forum members will install cams without verifying the timing (degreeing) first with no ill effects. I'd say the clearences are more important. Something to note is that if for whatever reason (tolerances stacking up as an example) the degree process yields results other than what's on the card (by a degree or two) unless you have the provisions to make a change, there's not much you can do about it. Timing sets with adjustment ability are available but if you don't have one, what do you do? If the clearences are within spec, just move along.

 

awesome, thanks a ton. i just got my old motor out and I'm cleaning the engine bay now so hopefully I'll get the new motor in there before the snow hits. thanks again, you've been a tremendous help.