lunaticinaZ

I'm looking at an engine. 350 puts out 350 hp. But the cam is flat tappit. What your guys opinions on this? The shop said they could do a roller cam and lifters for about $400 more. Should I go with roller or would the flat tappit be ok? I kinda feel like it"s taking a step back. what do you guys think?
This will be going in a 91 Z28

Orr89RocZ

iTrader: (20)

Its up to you and the goals for the car. Have to consider most oils on todays shelves are not designed for flat tappets, so you'd have to add additives to make sure the oil lubricates the lifters of the flat tappet.

400 bucks more for a roller seems like a good deal. Is this a retrofit roller because roller lifters are pricey by themselves for retrofit blocks. If OEM style block that can use factory roller lifters like the thirdgens do in 87-92, then 400 is abit of a rip off. you can get a roller cam for 150 bucks more than flat tappets and lifters for about 100 bucks more if using LS7's. That way it would only be 250-300 more than flat tappet.

Rollers are much more smooth in operation and you can get abit more aggressive on the cam design and lift. Not sure whats done to the motor or your future plans, but a roller is a great idea for decent hp builds and especially for a car that sees alot of street time.

I will never own a flat tappet cam. Rollers are my favorite. You can do alot with them.

lunaticinaZ

the car will be a street car only. But thats a good point about the retrofit. I'll ask the shop about the year of the block. and I didn't think about the oil either. The engine is reman 350 with 350 hp for $2195. but +$400 for roller stuff. For whatever reason this is kinda "scaring" me away from it. I keep pondering the idea of rebuilding the 350 I have myself. But I do agree that roller is better I just wanted to know what you guys/gals thought. Good points Orr. Really making me rethink this.

midias

Roller is better but flat tappet is still good. A lot of engines still run flat tappet. These engines are mostly diesel so go get some Rotella T diesel oil it has 1200ppm ZDDP and will work fine for flat tappet motors.


Get the best deal for what you want and just run the correct oil.

SDTransAM

iTrader: (5)

Rebuilding what you have would be the best deal. But building engines is not for everybody.

Roller cam is definately better, and the cam's usually last a bit longer. But you would be fine with a flat tappet cam if you run good oil. Break in process is EXTREMELY important for a flat tappet cam.

lunaticinaZ

That's also what I am worried about. the breakin process on flat tappet. I have heard horror stories about what happens when you don't do it right.

Orr89RocZ

iTrader: (20)

Also keep in mind a roller cam typically requires different valve springs than flat tappets. Some mild stock replacement type rollers can get away with less valve spring pressures and use similar flat tappet type springs but the more aggressive higher lift stuff for performance typically want/need/require stiffer springs.

Just another upgrade you MAY need to look at. What heads are on the motor? Can they handle higher lift cams? Alot of crate motor heads like GMPP stuff found on H.O crates likely cant...the retainer will hit valve guide boss at .470" lift or so. They also have press in studs which on a hot hyd. roller setup with stiff valve spring, could pull out. Very rare but could happen. Just another thing to think about.

midias

The break in is very important. I was worried the previous owner of my car did not do it correctly but when I got a chance to pull the lifters at 5k miles they looked flawless. He used the comp lube to break it in then rotella T for the first oil change. I used it for the second.

DeltaElite121

Flat tappet is cheaper, and there's a break-in process involved. I went with a flat tappet and put the rest of the money I had into my cylinder heads. I guess it just depends on what kind of money you're throwing down. My next build is a roller, but I like flat tappets and hydraulic rollers.

lunaticinaZ

[quote=Orr89RocZ;5139911]Also keep in mind a roller cam typically requires different valve springs than flat tappets.

The cam is .440 lift

Just another upgrade you MAY need to look at. What heads are on the motor? Can they handle higher lift cams?

The heads are "reworked" vortec heads. with performance springs. It don't go into detail to much about that but I will def. ask befor I make any decisions.
I'm going to email them a few questions today about all of this. If it is retrofit roller stuff do you guys think the $400 price tag is worth it?
And if it has a 2ps RMS what would I have to do to get that to work in my 5 speed? Different flexplate?

midias

[QUOTE=lunaticinaZ;5140456]
If I remember correctly 2 piece rear main seals are all flat tappet factory.

If it is retrofit roller with a roller cam and not a flat tappet cam with conversion lifters then $400 is not bad at all. Here is an example of a conversion kit
http://www.summitracing.com/parts/HRS-CL110235-12/

I don't think you should have any problem getting it to work with you 5 speed. I think you just need to get a flywheel for the correct 305 and same clutch.

lunaticinaZ

I just sent them a email asking what year the block is and with the roller cam upgrade if stiffer springs are included. I also asked if the do the break in process on their long blocks of if I have to do it. hoping they say they do it.... But I'll post their reply.

Orr89RocZ

iTrader: (20)

What cam are they using? .440" is very mild...thats smaller than L98 cam with 1.6 rockers. Sounds like LT1 cam of some sort which is mild enough to use most flat tappet type springs with 105 lbs on the seat, 250 or so open pressure. More is alittle better for safety on an overrev, but chances are you wont be turning this thing over 5500 rpm too much.

Steven6282

The engine I just put in my car recently is a flat tappet. I honestly don't know enough to know the differences between roller vs flat tappet, but I can say that I am happy with the performance of mine. I haven't gotten 3k miles on it yet so it's going to be a little while longer before I can check to be sure the break in was done correctly (if I have it checked at 5k miles). I paid someone else to do the break in and install because I didn't have a place to work on it myself even though I would have loved to do it myself.

I ordered mine through cmengines.com, not sure if that is who you are talking to but there are a lot of similarities in what you say to mine. .440" lift for the 350 performance upgrade with a "Lopey" camshaft in it. The price you said however is a little more than listed on their website. You said 2195 but cmengines.com lists it as 1891 (same that I paid when I got mine a few months ago). I mainly went with this one for the idle as it has that classic muscle car sound to it.

For the break in I made sure break in oil purchased from cmengines was used. And then for the post break in oil and the first oil change at 300 miles I just used a non synthetic with a ZDDP additive. The guys at cmengines told me that would be fine as long as I had at least one quart of the additive in there.

Oh and I can say if it is cmengines.com you are talking to, that price does not include the break in. I debated having them do the break in so I knew it was done correctly, but they wanted an extra 500 dollars to do the break in and then dyno it. I just couldn't afford that much more when the person doing the install for me would only take off about 150 dollars for not having to do the break in.

lunaticinaZ

I got a return email. They said if I chose the roller upgrade, it includes lifters, cam and stiffer springs. They said also that they would be using a 1996 or newer block. And yes STEVEN6282 it is cmengines.com If you don't mind, how does your engine run? Is it noticeable difference from a stock 350? I'm kinda on the fence about getting their 350 w/350hp or just building my own with a lt4 hot cam and aftermarket heads. So any imput you may have will be very helpful. And thanks for all the help guys

midias

Sounds like a roller block so it will have standard roller lifters. 400 seems a little pricey but not to bad usually roller cams and lifters are a bit more expensive.

In the end up to you, if you have a 350 I would probably just pull it and do a rebuild for less but that is just me.

Or have them send you a roller and sell your 350 for $400 if it is running.

Orr89RocZ

iTrader: (20)

Fairly good price if using 96 up block with factory OEM stuff. Figure 120 bucks for LS7 style GM lifters, 150 for decent valve springs, and 100-150 more for a roller cam over a flat tappet. Find out what cam tho, you could get decent performance out of this motor with a mild hyd roller cam and vortec heads. Vortec heads + LT1 factory roller cam is already near 350 hp and drives like bone stock car. LT4 hotcam is a 400hp motor easily and still very streetable. That cam is a baby and you dont even need to buy it new. can get it for 150 bucks used, same price as a new flat tappet.

I'd go roller and be done with it.

lunaticinaZ

[quote=midias;5144713]
In the end up to you, if you have a 350 I would probably just pull it and do a rebuild for less but that is just me.

Or have them send you a roller and sell your 350 for $400 if it is running.[/quot
I'm thinking of just building my own. But thats a good idea on selling my engine after I buy theirs. If I do.
LT4 hotcam is a 400hp motor easily and still very streetable
Orr. Thats exactly what I'm thinking. I may just buy a short block off of them and do the hot cam and aftermatket heads. Then sell my 350 like midias said.

Steven6282

I upgraded from a worn out 305, so I can't really say how the difference is from a stock 350. It was a huge upgrade from my 305. And I can also say it is a bit more peppy than a stock LT1 from a 97 trans am as well. I have another 84 camaro that I bought because it had a 97 trans am drivetrain swapped into it and I wanted the T56 tranny out of it. So I've driven it with the LT1, and I can notice a definite power improvement in my 86 with the 350 from cmengines. I'd imagine at 97 trans am LT1 is probably a step up from a stock 350 from a third gen.

As for how it runs, I think it runs pretty good so far. My best 1/4 mile pull in it so far has been right at 13, but I still have a lot of work to do to my suspension and rear end. I think I can get it into low 12s by the time I'm done with it. Which is right where I wanted to be, plenty of power to have fun with, but not so much that I'm going to be attracting the attention of every cop at a red light if I give it a little to much gas lol.

However I agree with others, if I had a 350 in mine when I was upgrading my engine, I would have rebuilt mine rather than buying the engine I did. I bought the one I did because I only had a 305 and didn't feel it was worth rebuilding the 305 (And for the record I didn't buy the camaro with the LT1 in it until after I had bought the engine from cmengines, otherwise I probably would've just rebuilt the LT1 as it had a bit more power than my 305 as well).

tater

iTrader: (10)

I have a flat tappet cam in my Chevy 350 in my '87 Firebird. I wiped out three lobes on break in. I have built many engines over the last 25 years. I took the engine apart to clean all of the metal out. The second try was successful!! However, since then, I have purchased a roller Vortec block and will not build a flat tappet motor again.

sofakingdom

iTrader: (1)

^^^^^^

I think I built my last flat-tappet motor (for myself at least) in about 1994 or 5. All rollers since then. Won't go back if at all avoidable.

InfernalVortex

iTrader: (4)

If you can afford it you should go roller.

If you can only afford a flat tappet, just be very careful with it and it will be fine. Good oils (research!), good seat pressures during break in, I'd probably avoid the more aggressive flat tappet grinds too.

tater

iTrader: (10)

Hone the lifter bores real well when using flat tappet cam. Those lifters HAVE to spin. Use lots of moly assembly lube.