What is needed? before i heard i just had to drill and tap the bosses to hold the spider but then I read something that the lifter bores are bigger on the non roller and you cant use a stock setup on it. So what is needed to be done to convert? I am thinking about changing heads and upgrading cam and figure why not go roller for a few more ponies while I am there. I am looking for exact information no I think messages...

I have a 91 truck 350 I am using.

Thank you in advance

 

You're right about the lifter bores, they different sizes. You'll need a set of retrofit roller lifters. Summit Racing and Jegs sell them, among others. I can't remember if the stock spider and dogbones will fit though.

Like these: http://www.summitracing.com/parts/lu...make/chevrolet. Shouldn't need the spider or dogbones with those since they have the link bar. You'll need 8 sets.

 

i have a truck motor that had a flat tappett cam in it and it was all set up for the roller cam i just put the new cam and all the roller parts in it no drilling tapping nothing all the holes were there and the lifters seemed to be the same size to me 87 and up one piece rear main seal should be an oe roller block

 

did you buy the truck new or used? it could have been a roller block that went to flat tappet i'd assume. "seemed to be the same size to me" is not the concrete info. I want. Thank you very much for responding though, it is much appreciated.

 

i bought the engine it was a gm goodwrench creat motor 95-2000 5.7l it had a flat tappet cam in it maybee its diff then what u have i took the lifters and spider and lock plates out if my 305 bought a comp roller cam and had to get a diff lock plate to hold the cam in cause it was diff good luck to ya man do u have the motor apart

 

The bores are the same size, .842"; which is why you (or the factory) can take the same block and put either flat or roller tappets in it.

The top of the lifter bores are however prepped differently in factory-roller blocks. They're a bit taller, and the top is machined off flat, for the figure-8 thing to sit on. And, the sides of the water jacket right next to the lifter bores, are usually carved into a bit in the process. Because of the added height, the "standard" link-bar roller lifters won't fit a lot of the time; the bars will sit on top of the bores.

Odds are, your block is one that only needs the drilling & tapping, and of course the "spider", figure-8s, retainer plate, and hardware, to put factory roller lifters in it.

Post a pic, we can easily tell you.

 

Okay thanks guys. No pic at this time. motor is car and running with hydraulic flat tappet cam. Was gonna pull engine out reseal, re-ring, and possibly retrofit to roller if can be done reasonably. I guess I won't know til it is out and apart. I was hoping to order parts before then to cut down on downtime of the car. Thanks for the help

 

I had planned on converting my 350 into a roller until I took it into the machine shop today to discuss a plan and when I was told what the lifters cost I decided I am just going to stick to the flat up upgrade it to a performance cam

 

You can get a roller block pretty cheap... best bang for the buck on aftermarket roller lifters are the GMP LS7 style lifters for like $138.

 

Who ever says the liifter bores are a different size are wrong. My 383 build is using a block from a 95 truck that was originally flat tappet. All you need is to drill/tap the holes for the spider, and drill and tap 2 holes in the from for the thrust plate.

Thrust Plate: http://www.summitracing.com/parts/na...8501/overview/

I just used 1/4-20 bolts for the spider and thrust plate. The bolts that came with the spider were actually bigger (idk what size) but it doesnt matter too much. Also torque specs

Spider: 18 ft/lbs
Thrust plate: 8 ft/lbs

I used blue (meduim strength) loctite on the screws.

Also, keep in mind the the bolt pattern for 87 and up cams are different from 86-earlier, so dont get the wrong timing chain.

Stock OEM setups run for $110

 

Thanks....so their are bosses on the front of the engine to drill out or no for the cam thrust plate? and I don't get a retrofit cam I get a stock style roller cam right? I want to run the xfi268 cam

 

Yup, stock style cam, not retrofit, and youll see where in needs to be drilled, there aren't any bosses like with the spider, you'll need one person to hold the plate center then have the other use a center punch to put two marks for where to drill the holes. Also use some oil when you drill (and obviously when you tap) because the bit will get hot quick, and start the hole with a smaller drill bit.

 

gotcha. not too hard at all

 

Nope, you wont have any problems with it. It's one of the more straight-forward parts to do. Are you just going to use an OEM setup from chevy performance? Thats what i went with and its decent quality stuff, but there's definetly better ones out there.

 

All 350 lifter bores are the same size from the factory. Summit lists two sizes because some guys enlarge the bores to properly lubricate solid lifters

 

A "roller ready " block has the castings for the retainer plate even if they are not tapped and the block was fitted with a flat tappet cam from the factory

 

Now is roller really worth all the extra money

 

That would be for you to decide taking into account your aims and budget

http://www.badasscars.com/index.cfm/...100/prd100.htm
http://www.chevyhiperformance.com/te...c_roller_cams/
http://www.lunatipower.com/Tech/Cams...tOrRoller.aspx
http://www.hotrodders.com/forum/flat...ce-176531.html

 

For your situation, yes, youre not spending that much more money than you would with a flat tappet because you can get a whole OEM roller setup at $110, which is a good price. The only time i can see a roller NOT being worth it, is for a budget or stock type rebuild using a block with out roller provisions, because the retrofit stuff gets very pricey. I see no reason for you not to go roller though. For the price of it, the benefits are definetly worth it, and it involves very little work.

 

People put too much emphasis on hydraulic roller camshafts. The only times you'll see massive gains from a roller is when moving to a solid roller, or if you've got a mild hydraulic flat tappet (in which case, EVERYTHING is better).

I wouldn't waste my time with it. You won't feel a difference with your build and your wallet will be several hundred bucks lighter. Even so - I'd take a solid flat tappet over a hydraulic roller any day of the week... that is, assuming we're using a flat tappet style block. Otherwise - mild solid roller all the way.

 

if i can get an OEM setup for 110.00 plus a cam for 300 so basically 400 or 200 for hydraulic flat tappet and new lifters. i guess it may be worth it if I get an addl 20 hp

 

going to need new springs, locks, and retainers if you get a cam worth it's salt unless you buy new cylinder heads.. and new pushrods on top of that. It's going to be more than $400.

 

I believe he has another thread about buying heads, so he should be ok with springs and all that.

Undercover: When you take the flat tappet lifter out, look at the wear on them, they are going to wear inward (concave) which in turn lessens your lift. This will not happen with a roller so you'll keep more consistent performance as the miles build up. Also, with less friction and many more chioces for higher lift, you'll see more than 20 hp gain. You also dont run the risk of a bad break-in and flattening some cam lobes with a roller cam as oposed to a flat tappet. Also factor in to your price that you would need new lifters for a flat tappet anyways (cant reuse them) so thats another $75-100 right there. So for the extra $100, you have many more cam choices, reduced friction and wear, and you have much less risk of destroying your cam on break-in.

 

So with his roller block you'd still be suggesting a roller, just a solid one, not a hydraulic one?

 

Solids are harsh(er) on valvetrain components, but mild ones tend to be much more friendly and easy to work with. That's the route I'd personally go, but you do need to keep your eye on things much closer with solid rollers. That, and lifters/springs are fairly expensive if you want something that is going to last. In a street car I'd probably say no if you're not intending to race it simply because you'll be replacing springs/lifters at a faster rate if driven extensively every day, but if you want good power increase and money is no object - solid roller all the way. There's always trade-offs to making good amounts of power. There's better ways to spend that kind of cash first (like cylinder heads). Most people probably shouldn't get a solid roller, but it's definitely a viable option if you're willing to take the time to do it right.

Also, bad break-in's are generally user error or bad cam cores. I have a premium core solid flat in my car and no issues. No problems on the prior hydraulic flat tappet I had, either. Get a good stick and good lifters and you shouldn't have problems with a flat tappet.

Don't get so caught up on HP differences between the cams. All things equal between cams - you probably won't make as much power as you think you will by just a cam swap. It's all about parts balancing together in unison for the whole package.. not just one component.

 

I will say that on the street, where we have to keep compression ratios down to work with lower octane fuel, the hydraulic roller cam is almost always a better choice than flat tappet and well worth the added cost, especially if you're talking aggressive lobe profiles. The roller tappet can follow a much more aggressive lobe than a flat tappet can. Therefore, performance roller cams can be cut with more lift and more full open time(faster ramps) starting from the same opening and closing points.

Definitely solid is always better for any motor that will see high revs. Largely because the solid tappets are much lighter due to being hollow. However, for street driven performance, engines that make peak power below 6,500 and under 550 HP, I would say hyd roller is the way to go. Much less maintenance for one thing. How would you like adjusting valves on your car every 5,000 miles? And that's with a tight lash grind.

 

I definetly agree with everything you said, especially about cam swapping wont make a difference with out proper supporting parts.

Also, I know wiping out a cam lobe is usually user errors or a bad cam, but what I'm saying is that with a roller cam you almost take both of those factors out of the equation. Soid rollers are superior for sure, it's just for his application I think he would be best off with a roller.

 

Yeah my car is actually a daily driver so I didn't even think about any solid setups. I am going to change heads so I would buy the heads with springs able to handle the roller setup. I am looking at comp cams 268 XFI. What is funny is the roller vs flat tappet version of that cam. I like the duration of the flat tappet I know that'll be a good duration for the sound I want. Yet the lift of the roller is higher due to being able to have increase ramp rate with the roller setup. I will have to look into have more of a custom cam. I know more duration is more fuel I am okay with that. I have no problem paying for what I want.

 

And youre right about not noticing much difference if the cams are equal, just one is a roller and on is flat tappet. But like ASE doc said, one of the biggest advantages of a roller cam is the ability to get an agressive ramp up/down on the lobes, leaving your valve open at peak height the longest. But obviously you need heads, springs, valvetrain, etc to fully use the cams aggressive profile.

 

I would recommend calling Steve Slavik @ Lunati. Get a custom grind on a voodoo cam. The voodoo style have awesome torque curves and Steve will work with you to get the best cam.

 

Once again another misguided person buying a cam for " the sound".

One of the not already mentioned benefits of a roller cam is a greater valve lift potential without the added duration required to get that same lift on a flat tappet cam.
Better idle , better throttle response from the shorter duration with the top end benefit of large lift.
A noticeable tuning benefit on EFI engines because the ECM doesn't like the excessive valve overlap @ idle that comes with long duration cams
With a carb engine ,the cam duration and LSA are not of the same consequence they are on EFI

 

Not to mention it's not hard to just get the same duration in a roller cam. The difference is that the roller cam makes more power with the same duration at a whole lot higher lift. You dont HAVE to go smaller on a roller cam, you know...

Plus a roller cam is going to be far more reliable long term than a flat tappet cam, especially a big one. No more worries about oil quality and zinc levels and break in procedures and so on.

Alot of solid roller lifters arent really intended for street use, also. They're not designed to be adequately oiled for long periods idling/cruising. Keep that in mind.

Also, Howards has retrofit roller lifters specifically designed to clear tall bore truck blocks that don't have the proper machining to use OEM roller hardware. The main issue I think is the machining of the top of the lifter bores. My block doesnt have this, so the dogbones don't really have a good way to sit on there solidly.

 

I don't see how I'm misguided because I want a certain sound out of it too

 

Of course you don't, or you wouldn't want it that way... no one who approaches it that way ever does...

But buy cams based on "sound" a time or 2, and you'll learn.

It's a common mistake of inexperience. Seems like a good idea at the time but almost always leads to putting in too much cam for however much motor is available. Virtually always runs weaker than THE RIGHT cam, with a lot less "sound", would; and tends to cause other problems as well, starting with very poor gas mileage, poor reliability, and terrible driveability, then going downhill from there.

I will never again build a non-roller engine if I can help it; too much risk of catastrophic failure, these days. Times have changed and what worked in days gone by no longer does. Take advantage of the cheeeeeep factory roller setup; might cost a bit more, but is AHELLUVALOT cheeeeeeeeeper than tearing it back down and replacing the crank because a lobe rolled off and shed metal into the oil and wiped out all the bearings, and THEN putting a roller in it.

 

Buying a cam for sound isnt a terrible thing to do, just dont comprimise drivability, performance, or reliability for it. If youre going with a good aftermarket cam, a good set of heads with a good exhaust system to match, youre going to get a good sounding engine either way.

 

Anyway back to thread topic. Roller is better. I know the details to get it done. Thanks for the info

 

Yessir, one other thing to watch out for is that some of the bores for the lifters might be a little tighter than the others and some of the lifters might be a little big than the others. This happened to me so i kept moving the lifters around to different bores so that all of them went up and down smoothly with little force. I did this because i had a lifter that i couldnt get into the bore at all, I would drop in a little bit but wouldnt sit anywhere near the cam.

 

268 degrees of advertised duration will have a nice, slightly lumpy idle. Idle quality with any cam is affected by several other things. Base timing, compression, and fuel mixture all affect actual idle quality. As you get into the higher duration numbers you will need to run higher than normal base timing just to get a drivable idle. Matched with 9.5:1 to 10:1 CR and 190-195 cc heads and the right springs, and an intake system to support it, it will also produce a good power band and 400 hp pretty easily. As vetteoz said, the cam must be part of a complete engine design package in order to work.

My ZZX cam at 290 advertised, 240 @.050, .560 lift, and 112 degrees LSA sounds alot like an old school Z28 375 HP 350 flat tappet cam at idle with 22 degrees base timing. Matched with my ported to 197cc Trickflow twisted wedge heads, 10.2:1 compression, dual roller springs with 145 lbs seat, 400lbs open pressure(at .560), and an intake system to support it, it also makes excellent power and is very drivable. Long tube TPI, as much as it has been modified in this application, is the limiting factor for peak power, though it also has alot to do with the great drivability. When I finally swap to a modified HSR, I know that I'll have to go to a higher stall speed and give up the lower mid range torque that I enjoy now in exchange for more peak power and higher revs.