Years ago I read an article....I know not where....that claimed a roller cam, all other things being equal, would free up as much as 30 HP.  The reason we have them now is due to EPA rulings regarding zinc in motor oil and the attendant emissions.  If for no other reason than the availability of zincafied oil, I would only mess with a roller.  IMHO

The cams are made from different materials, and sometimes have the added step of an iron gear pressed on instead of machined (so the original distributor gear can be used in the event of a retrofit).  The lifters are more complicated because they have to have the roller portion on top of everything else a lifter already has, and then add link bars if they are retrofit lifters.  I will say the cost of retrofit lifters has exploded in the past 10 years.  They used to be a lot more reasonable.  Not sure if this is a demand thing or what.  Ford stopped making non roller production blocks sometime in the early '90s, so the newest non rollers are 30ish years old now.  If starting a new engine build without a core you're always going to be bucks ahead to just grab a 5.0 or 5.8 block that has the provisions for a factory roller setup. 

Power wise, peak numbers are going to be peak numbers.  A cam ground with a certain lift and duration and LSA is going to make the same peak HP and torque within 10HP roller or flat tappet.  Any benefit to peak numbers is the result of the reduction in friction that comes with rollers.  However, most tests I've seen comparing this also go to roller rockers, so exactly how much gain is cam and how much is rocker remains unclear. 

However, peak numbers don't do the roller justice.  Where you benefit with a roller is everywhere else.  The issue with flat tappet cams is that the ramps can only be made so steep because at some point the edge of the lifter digs into the lobe of the cam.  This is why guys in racing sometimes swapped to larger diameter lifters or used mushroom lifters.  A roller lifter isn't bound by this, so the ramps can be much steeper.  This snaps the valves off the seat faster, so low lift flow and power is improved.  This can be worth 20lbs/ft of torque on the low end and in the midrange, exactly where a street engine benefits from added power.  This is why guys talk about "area under the curve".

Personally, I haven't built a non roller engine in close to 25 years, and its doubtful I ever will again.  Having experienced both there's no comparison, and I've yet to find the engine I thought had too much low end or midrange torque.  To me its money well spent, even if you have to retrofit it. 
 

A cam swap alone isn't going to set the world on fire anyway.  If that's the consideration I'd just keep running it.  The decades old head technology is more of a hindrance.  I remember AFR picking up 80HP on a stock 5.0 by swapping to a set of their heads.  Stock cam, stock exhaust even.  I agree spending $1,000 on a cam swap to gain a little HP and torque probably isn't worth it, to say nothing of the work involved.  I'd do heads, intake, carb, exhaust, and cam, and by that time the question of how sound is the short block comes into play and it usually ends in an engine build, and if you're doing that anyway why stay at stock displacement?  This is how I went from a 225HP stocker to a 450HP 331 in my '89 GT.  I think a lot of us have followed a similar path.  If you can keep your sickness in check I admire and maybe even envy you.  Mine is so far untreatable...

Definitely doable without a roller, but a 300HP roller package will be a better driver, particularly if the engine is smaller (302/289).  A 5.0 with AFR heads should already be at or above 300HP with a stock cam, which will also already be a roller.  I'd go to a 1.7 roller rocker, put headers on it, a decent intake and carb and you'll be good to go.  Probably more like 325HP and tons of low end, but will still wind to 6,000+. 

Keep in mind that a set of AFR heads picked up 80HP on an otherwise stock 5.0.  That was a 225HP engine stock, so it was over 300HP with just the AFR heads.  Now, its an EFI engine and it was professionally tuned, so you've got to backtrack a bit, but the engine was using the stock pinched down headers!  My build advice would be:

Fresh 5.0 shortblock.  Target 9:1-9.5:1 compression.
AFR 165 heads
Cam selected by Crane, Comp, etc. tech department
1.6:1 roller rockers (Crane)
Edelbrock Performer RPM intake
600cfm carb
1-5/8" headers feeding into 2-1/2" dual exhaust with crossover

Get that sucker tuned right and it'll make 300HP all day long and should still have great street manners.  You should be able to run this on mid grade fuel even with an aggressive tune up.

Ideally this gets paired with a manual trans and a 3.50-3.73 rear gear. 
 

Seems like a good way to attack the roller vs. non roller blocks would be to machine the lifter bores and install replaceable sleeves, like sleeving a piston.   I wonder why doing that didn't become a popular option?   Probably cost... but that would be the best solution.

BILLY WALTON from GEORGIA wrote:

I wanna leave the Hi-Po manifolds on not realy wanting to go back to headers unless its some shorties.
 

The HiPo manifolds are pretty decent.  You're probably giving up a few ponies with them vs. headers, but probably not enough to worry about at this power level.  If you do get headers I would only run shorties.  Based on my experience and what I've read here I would go with FPA.  Pricey, but they seem to clear everything where other brands don't. 

MS wrote:

Roller lifter blocks have taller lifter bores to accommodate the factory style longer roller lifters. Ask jhudgin why you cannot put factory roller lifters in a non-roller block.

Link-bar lifters are for retrofit applications in non-roller blocks. I have not heard of any problems using them, but my preference is to find a 5.0 roller cam block and use factory style components. 5.0 blocks used to be easy to find, but are now getting more scarce. I have two I am hoarding for some future use.

The only downside I've seen is cost.  I've had link bar lifters in a couple different engines and never had an issue.  This is why I would advise a person to find a 5.0 if they are basically starting a build from scratch. 

TKOPerformance wrote:

Greg B wrote:

Seems like a good way to attack the roller vs. non roller blocks would be to machine the lifter bores and install replaceable sleeves, like sleeving a piston. I wonder why doing that didn't become a popular option? Probably cost... but that would be the best solution.

The issue isn't the diameter of the lifter.  The diameter is the same roller vs. flat tappet.  The issue is the upper part of the block around the lifter bores.  A stock type roller that uses the dogbones and spider instead of link bars only works in blocks that accept them.  Not sure if the older blocks could be modified for this or not, but the cost owould probably be the same as the cost difference between the link bar lifters and the stock style or more. 
 

I'm aware its a length issue.   This process is already popular in more rare engines (Mopar) and such.  Plus every aftermarket race engine out there.   Years ago, it was a 600 dollar operation.  No telling what costs today.    Hell, I even remember lifter diameters.  Off the top of my head.   Chevy was .845  Mopar .904  and Ford .875   This is done in race engines to perfect lifter centerline alignment.  Total overkill for a stock block.   But....my point was its out there.   So many ways this COULD be done.   In my opinion, some of the solutions are stupid, confusing, and pricey.   Hec, I even think just making a roller lifter with a relocated oiling hole could solve the problem.    There has to be a cost effective way to do this...
 

BILLY WALTON from GEORGIA wrote:

MS wrote:

?

the block has XXX on the side    I was trying to research it a little to see what it meant..

.

Com'on BILLY..........everybody in Ga. knows XXX is a pro rasseler!!!!
6s6
 

Greg B wrote:

TKOPerformance wrote:

Greg B wrote:

Seems like a good way to attack the roller vs. non roller blocks would be to machine the lifter bores and install replaceable sleeves, like sleeving a piston. I wonder why doing that didn't become a popular option? Probably cost... but that would be the best solution.

The issue isn't the diameter of the lifter.  The diameter is the same roller vs. flat tappet.  The issue is the upper part of the block around the lifter bores.  A stock type roller that uses the dogbones and spider instead of link bars only works in blocks that accept them.  Not sure if the older blocks could be modified for this or not, but the cost owould probably be the same as the cost difference between the link bar lifters and the stock style or more. 
 

I'm aware its a length issue. This process is already popular in more rare engines (Mopar) and such. Plus every aftermarket race engine out there. Years ago, it was a 600 dollar operation. No telling what costs today. Hell, I even remember lifter diameters. Off the top of my head. Chevy was .845 Mopar .904 and Ford .875 This is done in race engines to perfect lifter centerline alignment. Total overkill for a stock block. But....my point was its out there. So many ways this COULD be done. In my opinion, some of the solutions are stupid, confusing, and pricey. Hec, I even think just making a roller lifter with a relocated oiling hole could solve the problem. There has to be a cost effective way to do this...
 

Yes, in race classes where you were stuck using a flat tappet cam some guys would machine the bores to accept a Mopar lifter, if mushroom lifters were against the rules.  This simply allowed you to run a larger diameter lifter which would tolerate a more aggressive ramp.  Mushroom lifters also required machining, and then had to be installed from the underside before everything else.

Then there was the issue of valvetrain geometry, so some guys would machine the bores oversize to correct any amount by which the lifter bore had wandered off center from the center of the rocker (so the pushrod wasn't operating at an angle).  High end blocks now often have lifter bores that are sleeved with replaceable sleeves, and some heads have such big ports that they move the pushrods so much they require offset cups in the lifters.  This is all high end race stuff you would only consider when trying to make upwards of 800HP.

To return to the original issue, a roller vs. a non roller uses the same diameter lifter within the same engine family (Ford vs. Chevy vs. Mopar), so the only reason to monkey with the bore diameter would be to run a different manufacturers lifters.  Ford made the lifter bores taller to account for the dogbone and spider arrangement they used for their factory roller setup.  The only way to make the bores taller would be to machine the tops of the bores flat and install some kind of spacer.  If the thought was run the dog bones on top of sleeves that are taller I don't think that would work for a variety of reasons, the biggest being that the sleeves would be relatively thin, so I think wear would be an issue.  There's just not that much meat in the block between the lifter bores. 
 

It sounds like you found a roller block so I would go the roller route. Yes, it might be expensive to get a roller, but I thought it was worth it for the 67. Read through the forums to find out how many have lost a cam lobe on break in with a flat tappet. Think of the price difference for flat tappet vs roller and how much additional cost is involved to go through the same motor twice!!