[kennyhammond]

i am looking for a cam for vortec 350... i am going to use a flat tappet cam looking for somethen to make alot of noise... wnat a good rough idle.. i know it wont run great thinking like this but ...i have my reasons... what makes a cam idle rough..the duration or lift..

[krypty]

comp cams #12-600-4 will make alot of noise

[Silver Surfer]

A rough idle is determined by:
1) intake valve closing (the later it closes, the rougher)
2) Valve overlap (more overlap the rougher)
3) LSA (smaller number the rougher)

All these factors cause reversion, that is intake charge is reversed and pushed back up through the carb. Comp Cams makes a line of cams called "Thumpr" that is intended just to rattle and make noise. Performance wise they are not that great. They are just designed to thump.

COMP Cams: Thumpr™

[kennyhammond]

Should have added I am using vortex heads so I can't go over 480 in lift and I am on a budget..... this is a request from customer ....so cheap is what he wants but wants to sound like a street machine.... its a big argument ...but that's what he wants ...is there any cheaper can to use to get this

[Silver Surfer]

Well you are getting a new cam and new lifters, so having the valve guides ground down isn't going to add that much to the cost. You can even get a tool from Comp Cams or Crane Cams to perform the work yourself if you don't want to send them off to a head shop. Also the 279TH7 Thumpr cam has 0.479/0.465" lift so that meets your reqs.

[kennyhammond]

Cost are high for those cams ...didn't know if a seal power can would work ...or what to look for to choose a rough idle cam...like lift ...duration..? Thanks for all the help

[ap72]

What does he have for an exhaust? What headers, pipe, mufflers?

If he has a good exhaust i'd run the 1785p cam from elgin. It needs a good exhaust setup though. There are videos of it on you tube to give you an idea of sound.

For mufflers id use thrush welded mufflers. Great sound and very reasonable price.

[kennyhammond]

Set of Hooker headers.. 2.5 dual to a set of raptor mufflers in a H pipe setup.... I can't first d any videos of the cam.... the Guy wants 2.02 heads cantly bad...but I can't afford them I have a good set of vortecs in the shop....

[ap72]

Get rid of the h pipe. Is the customer wants certain heads why don't you sell him that?

[kennyhammond]

This is a build for a trade....no money ..... this build is out of my pocket.... so trying to keep it cheap cheap but decent power he is looking for 300hp out of the 350..... I figured the vortecs the can mentioned above and a airgap I take should make 350-400 hp or so

[ap72]

That's a reasonable guess.

[kennyhammond]

What about speed pro cs1145r can.....or would the xe268 be any better I liked the elfin can that's the one I am looking at as of now ....going to use the roller lifters with this can also

[ap72]

You do realize you can't run roller lifters on a flat tappet cam right? At least not on pushrod engines.

[kennyhammond]

Nope...thanks tho.. if I was to take these vortex heads and use them on a 85 Moslem 350 what is needed to run it

[my87Z]

you mention that this is a vortec 350 which automatically makes me think that this is a 96'-00' vortec 350 motor. if so these were factory roller lifter cam motors and the lifter bores are larger in diameter than the older flat tappet style motors. running a flat tappet lifter in these motors is not going to work, that lifter will slap all around and the cam nor lifters will last longer than the time it takes to break the cam in.