Hello, I have a 79 355ci, Hookers w/ auto and 355's. I have a fresh 355 all stock. I want to go AFR 180 heads. I have a 962/L82 cam 224/224 480/490 w/ 1.60 rockers. Or should I use a 224/230 501/509 roller? The AFR,s flow around 260cc. I know I can use the stock torque converter w/ the L82 cam, what about the roller, stock converter? I want to max out the AFR's maybe 450hp. Thanks, Al

 

The AFR,s with the roller cam will make a really nice combo. The will make great torque, and also have no trouble making power at high RPM. The stock converter may be a little tight for the roller cam, maybe stepping down to the next smaller cam size would be better. It would give you a little more torque down low, and also be able to rev to 6000 without troubles. AFR also says that you can be conservative with the cam and still make good power with their heads. With all the troubles flat tappet cams are giving these days, I would shy away from them.

 

Flat tappets are not giving trouble these days. People are giving trouble. If you don't do your homework, and use the wrong oil, that's trouble. Flat tappets are just as reliable as they were 50 years ago, oil has changed, that's it. do your homework and use the combo that you think is right for your application.

BBTank

 

BBT, Your right, the flat tappet components are good products, and using the correct oil, and break in procedures will solve the lobe flattening issues. I just think that government restrictions on additives in oil and emissions will only get more restrictive. Down the road a few years a quart of oil "good" for a flat tappet cam may hard to find...and expensive. I just think rollers are the way to go today.

 

The roller cam will allow you to use the AFR heads to their full potential. My opinion on wht so many flat tappet cams are failing is
1. the modern oil don't have the additives needed to protect them
2. The modern fast ramp rates are right at or surpass the hydraulic intensity that would be considered safe when engineering for durability. This subjects the lifter, cam lobe interface to much more pressure than your lazy ramp rate L82 cam. It also improves performance substantially.
Read this to understand why all the cam companies are doing this in their performance cam lines.
http://www.harveycrane.com/duration.htm
and this.
http://www.enginebuildermag.com/Arti...r_failure.aspx
If you want the performance of a fast ramp smart $ uses a roller cam today. Seen to many fast ramp flat tappet cam failures to recommend one to anyone.

 

in my vet 350 i have a 540/560 roller cam . in my camaro 383 i have a 490/490 hydraulic. both have same transmission , same gears . vet has 3000 stall and camaro 2500 stall.

the difference is the vet rev,s so much more free. its electric. the camaro although having the extra cubes is not far behind it. little bit nicer to drive but here is what i think....

for 25 % of the price the hydraulic was the way to go. sure i love the roller cam but in all fairness i had to put in heavier springs, non standard pushrods, the price of the roller cam and lifters alone is way more. in the end it comes down to cost. is it worth it ? i dont know , prob not but it is good to have if you have big pockets.

all these people saying they are having trouble with wiping lobes in hydraulics i think arent installing them correctly.
-not enough lube on cam , lifters
-incorrect setting up of lifter
-not using cam run in oil
-and by that i mean for the first 300 miles
-etc etc

i might be just lucky but have not wiped a lobe yet.

 

Is the cam in your 350 the GM 847 cam?

 

I Agree with all that list, Hyd. Flats, pose potential and real problems for a High performance engine build these days. Also agree it will continue to worsen. Its been a few years now , that Hyd. Roller lifters and cams will make for a much more reliable and powerful engine build. Its the main reason I went with the GMPP 383 shortblock for my car last year. Good luck with the project.

 

all these people saying they are having trouble with wiping lobes in hydraulics i think arent installing them correctly.
-not enough lube on cam , lifters
-incorrect setting up of lifter
-not using cam run in oil
-and by that i mean for the first 300 miles


add
Mis-Matched Cam/Lifter set
Improper Valve Adjustment

etc..etc... I just went with Comp Cam XE series hydraulic and matching lifter set, Z28 springs and broke in with RP break in oil. No issues. I will run some RP XPR for a while and then eventually switch to VR-1. I am not worried at all.

With that said, there are some excellent reasons to go with a full roller set up....but it is expensive when using a legacy block....and since I am not racing the car and only driving on nice weekends etc saw no need to spend that money... I did go with some nice Scorpion performance roller rockers....which is still probably a waste of money.

peace

 

I'm one of the guys that didn't do my homework.It has been many years since I did a rebuild,and wasn't aware of all the government involvement in lowering the zinc,and phosporous.I broke the cam in fine w/EOS,and used good zinc content oil,then switched to Rotella,and now the car is sitting w/out the cam,and lifters.I wiped them in about 850 miles.
It was set up right,and have never ran anything but solids,so know how to set lash.I just changed to a oil that wasn't right,and now mean green sits......
I am going to go roller,or throw this engine back to gether,and build this 377,or 421,and go roller in it.
I would rather spend alittle more now,and take the guess work out of it,and the time involved to repair this.And....Mako's proding.

 

Nice avatar.

Seems like a lot of the failures are break in, mismatched parts or oil related. But there is an increasing instance where everything was done right and new builds are wiping lobes in under 2000 miles. Here is my thought, you spend in excess of $3000 on an engine build ( a lot are over $5000). A complete retro roller setup is around $1000. Subtract the $400 you would spend on the flat tappet setup and pushrods. Subtract the $2.00 plus per quart extra you will spend on high zinc oil for the life of the engine. (this is $100 per 30,000 miles if it holds 5 quarts.) That means it cost you an extra $500 for a roller over a flat tappet if you drive the car 30,000 miles, minus the fuel savings that a roller will more than likely give you due to better efficency. Then add in the increase in horsepower and street manners. $500 don't buy a lot of horsepower on a performance build. If you are one of the ones that do wipe a lobe it could very well mean a complete rebuild or at the least another cam set and gasket set plus the labor to change it all out and the metal particles from the wiped lobe floating around in your new engine. That $500 savings is gone plus a lot more, if your new flat tappet don't make it 30,000 miles. With the fast ramps on these performance grinds and the extra pressure at the cam, lobe interface due to the ramp rate, not stronger springs, 30,000 miles would be a lot of miles. If I am building a nice street performance motor that I plan on driving there is really no better $500 I am going to spend than a roller cam upgrade. JMHO

 

Read this Super Chevy Article.
http://www.superchevy.com/technical/...ock/index.html

They did a back to back compare of a flat tappet and hyd roller. The flat tappet spec'ed out at 230/236 at .050-inch and .490 lift with an LSA of 110. The roller cam was just one they had in the shop, 218/224 at .050 with .570 lift and an LSA of 113. Much milder.

Here are the dyno charts. The roller lines are blue.


Flat tappet: 375 hp at 5,500 rpm, 409 pounds of torque at 3,800, less than 11 inches of vacuum at 1,000 rpm idle.

Roller: 387 hp and 416 lb-ft of torque with over 17 inches of vacuum at 1,000 rpm idle.

Bottom line. Equal or better power with a more street friendly cam by going roller. If cost is not an issue, spend the extra $500 for a win/win situation.

 

live and learn - could have happen to anyone. My engine guy talked me into going roller before I really started doing research - lucky for me I guess.

I - under no circumstances - wanted to have to pull a fresh 350 after a complete frame off due solely to flat tappet issues.

I think Mako is on to something - his posts on the subject convinced me I made the right choice by spending the extra $500 on my roller conversion.

Apparently the new auto oil sucks - you gotta buy specific and/or run the proper additives.



2 weeks after picking up my sb I got to see a very similar 350 build run on the same dyno - the builds were very close with the main diff being cam type - roller vs tappet.

Cams were both hyd and in the .510 @ 230 range

The roller cam 350 was avg 40hp and 40ft/lbs stronger between 3200 and 5800rpm.

 

I've had an XE274H hydro flat tappet in my 383 for the past 25k miles and run REGULAR oil, no rotella or whatever. Car has always ran perfect and I've had 0 problems with the cam.

 

One way to realize the difference from the Manufacturers point of View Is to read the disclaimers from Comp, Crane and the old and great Iskenderian. All know they would be finished if they didnt develop and refine Roller technology for use in old style Blocks. I'd bet they wish Hyd. Flat Tappet tecnology would go away completely..they Cringe at the possible warranty dispute evey time they sell a flat tappet KIt.

They cannot stop manufacturing Flat tappet cams and Lifters, Their industry would not allow them to just do away with it because of technical changes within the auto industry. They do still work. Its just more risky even for experienced Engine Builders.

Anyone with success with their Flat tappet Build, your not alone , Most are doing just fine. Your doing fine as anyone.

I see the point of this thread as merely Valuable info for anyone from pro's to first time engine builders , what the facts of the matter actually are.

 

I had a friend in the Air Force that justified not combing his hair by adding all the time that you would spend combing your hair. It totaled something like 2 and 1/2 years. You can justify damn near anything YOU want to do.
Everybody on this thread has said the same thing, lack of knowledge is a cam killer. Dispute that, as this forum is always so famous for.

BBTank

 

I would not use 180 cc heads on a 355. They are only marginally better than ported stock 2.02/1.60. I ran 200 cc for years.

If you have the money roller cams are the way to go

 

Your earlier post says flat tappet cams are just as reliable as they were 50 years ago. they are. Actually they are better manufactured and tempered than they were then. 50 years ago flat tappet cams all lived within a reasonable hydraulic intensity and the oil all had 1400 PPM of zink and phosphorous. If you install a 50 year old lobe profile, properly break it in and use oil that has enough ZDDP in it it will probably last the life of the engine.
A lot has changed in 50 years though. Now no one is happy with that 50 year old lobe profile. The 1970 LT1 was 370 HP. This was with 11 to 1 compression and a barely streetable cam. Now you can build a 450 HP 350 with 10 to 1 compression that has good vacuum and runs on todays pump gas. Cam and head design is the big difference.
The ramp rates keep increasing on the performance grinds as every manufacturer trys to edge ot the competition by pushing the limits of engineering sanity sacrificing durability for performance and the oil has less and less protective additives. There hasn't been a stock flat tappet engine built for over 20 years. Rollers are a lot more money to build and design yet all the manufacturers went to them long before oil quality ever became an issue. Use what you are comfortable with. Just stating my opinion. Everybody else is entitled to theirs.