What are the advantages and disadvantages for each type of cam. If i was to use a roller cam what years of the 350 block would i need to look for in order to use a roller cam. Any info will be appreciated. thanks

 

The advantages of rollers over flat tappets are reduced friction which results in higher HP, lower fuel consumption, incresased longevity, and lower oil temp; and elimination of the lifter rotational accleration issue which limits the steepness of the ramps that can be used without sacrificing longevity. With rollers you can create far steeper cam ramps, which produce faster valve action, which results in the valve spending more of its time farther open without increasing the seat or .050" duration, which means more performance with the same emissions and gas mileage.

There are no advantages to flat tappets over rollers, except cost.

350s only from 67 up can accomodate roller cams. 265s, 283, and 327s from 55 up can use them. However, 87-up ones came from the factory with their twisted perversion of a roller system in them, and the roller lifters for them are much cheaper (being a stock replacement situation) than the type of roller lifters that all the rest of us had been using all those years we've been building roller motors before the factory caught on to the idea and butchered it.

 

There is ONE advantage of flat tappets: fewer moving parts and less likely to fail....but I have never heard of the roller mechanism ripping out of the roller lifter so I highly doubt this should even be taken into consideration. Rollers are much better, hands down.

 

Cost is the main benefit of the flat tappet hydraulic cams.. although that' being said i'd rather run one than the factory type roller setup.

There are a few things that add up to on the cost of the flat hydraulic cams that do help, beyond the inital cost of just the cam.

Springs cost far less... with the seriously lower spring pressures the springs are far more reasonable.. a very good set can be had for around 50 bucks give or take.

in most cases there's no need to put in screw in studs.. because the spring rates are lower and the lift is less.

generally no need for guideplates... as well.. which means not only do you save the cost of guideplates.. but also on the less expensive pushrods.

All those factors Do add up rather quickly. If the goal is for a street warrior weekend cruiser type that's supposed to look good and go fast... no goals of being in magazines for trick setups... under 500hp... or even slower than mid eleven sec passes.. a standard hydraulic flat tappet cam will fit your budget ... if your counting dollars and wanting to spread the extra4-500 bucks on the trick cam setup on other go fast or look good ... goodies.

 

Flat tappet cams wear out significantlly faster than rollers. Infact Roller cams can be reused almost an infinate number of times. Flat teppet cams eventually tend to flatten lobes. The only real advantage to flattappet cams is cost - a good flat tappet cam + lifters is around $200. A roller + lifters is closer to $600.


And RB you are such a smart @$$. I giggle everytime I read one of your posts.

 

Here is a pretty good article that was tested. Just remember that Valve float with a roller is usually 6200 rpm's, so if you spin it past that it can spell trouble. Beside cost, most will run a flat tappet rather over a roller if they plan on hitting the higher rpm's.

read this:

http://www.idavette.net/hib/camcon.htm

 

I disagree.

 

I have heard of the rollers falling out of a lifter before. Its by far not a common thing, but it can happen. Wouldnt keep me from running one though.

 

I disagree as well. Roller cams can stand up to more than just 6200 rpm. Valve float only occurs if the valve train isn't properly setup and balanced. Pair the right cam with the right springs and rockers, there's a very minute chance of valve float. Add a little more cam to a LS6 and you could push the shift point from 6200rpm to 6500+ easy; just an example.