My "tick" went to a pretty good "clanking" in no time. Pulled the valve cover late last night and found out that I am the lastest victim with a flat tappet going bad. I think I have an effective lift of about .284. As I run the numbers, the cam had WELL under 1,000 miles on it.

I am done with flat tappets....period. What sucks is that I got caught, as we all do, a little too early on when I wanted to make some major changes to my motor. I now realize that I am going to have to buy 2 roller sticks because the one I will need down the road is one I just can't run right now. Since I can go big down the road, I want to make sure that I "match" the best possible profile with what I am running now. Here is the current setup that was running VERY good.

'73 454 with stock, low compression
stock 781 heads
cam is 272H .515 single pattern 110 LSA
Big ole Performer 2.0
HP Carburetors 650 HP Holley
1.75 headers with X pipe and 40s
TH400 w/ 3,000 stall and 4.20 posi out back.

I'm usually pretty good at picking flat tappet cams but the characteristics of a roller are different. Valves open really quick, stay open longer and close quicker. Because of this, I don't know if I just transfer over my old cam specs or if there is other concepts. I realize I will need new springs. I also realize I need retrofit rollers. What is the difference between horizonal and vertical bars? I hoping since I am not going too big that there is a spring that will not require me to cut the spring seats. Thanks for any thoughts and for anyone that has gone down this road.

Dub,
One thing that I have been doing on all of the Big Block hydraulic rollers is to use the late model Gen 6 cam. Then you can use the stock gen 6 retaining plate and you dont have to mess with a cam button etc. You do need to use the late model timing chain set to match.

Where can I find out more about this? Thanks Bill!

Just curious for my own information. Did you happen to change the springs to match the cam ?? Also what oil were you using?? I have about 300 miles on my 274 Comp XE cam in my 396 and I'm hoping for the best. So far, so good. Thanks.

I did not exactly match the springs to the cam but I did have aftermarket spring. I broke it in and had additives for awhile then change to full syn. Not sure if that was the part that screwed up on. It's the 2nd BBC lobe I have lost in my lifetime. I don't know if I will know for sure but I'm not giving it another chance. From now on I will "roll on"!

I did not exactly match the springs to the cam but I did have aftermarket spring. I broke it in and had additives for awhile then change to full syn. Not sure if that was the part that screwed up on. It's the 2nd BBC lobe I have lost in my lifetime. I don't know if I will know for sure but I'm not giving it another chance. From now on I will "roll on"!

Yeah, I know what you mean. Only time will tell with mine. Thx again.

Yes, you'll need one of the retro-roller cam kits for your Mark IX BB.

You have a lot of disharmony in your build which makes recommending a cam difficult; 8.25:1 compression, 3000 stall, 4.20 rear gears, 650 cfm Holley (too small for a 454,..even the factory topped 454's with a bigger 750 cfm Q-Jets in 73), etc.

Any chance a new set of heads are in the budget?

Yes, you'll need one of the retro-roller cam kits for your Mark IX BB.

You have a lot of disharmony in your build which makes recommending a cam difficult; 8.25:1 compression, 3000 stall, 4.20 rear gears, 650 cfm Holley (too small for a 454,..even the factory topped 454's with a bigger 750 cfm Q-Jets in 73), etc.

Any chance a new set of heads and carb are in the budget?

I hope you plan on disassembling the engine and cleaning out the metal from the cam lobe. If not you will more than likely wipe out the bearings and cause more damage. Been thru that!

I did not exactly match the springs to the cam but I did have aftermarket spring. I broke it in and had additives for awhile then change to full syn.


Matching the springs is important NOT just using "aftermarket"

On a Flat Hyd I would never run Full Syn.

After break in with additives I always run 10-30 NON Syn with a good additive like Comp or Lucas on every oil change. Cost about $15 a bottle but good insurance. I only drive enough to change the oil a couple time a year anyway.

I have had good luck with Joe Gibbs "hot-rod"" oil. 10/30. I have two motors for my 68 Z; 302 with a 30-30, and a 355 with a comp cam. Both are solid lifters-no problems yet. About 1500 miles on each motor.

Good Luck

Agreed you really do not have enough Static Compression to Retro-Fit a Roller Cam. With an 8.5:1 Static, a HFT Cam between 266 to 270H-10 would be appropriate. I would recommend the CCA-924 Springs and buy good HFT lifters like Morels or if you can find them OEM or Old Stock TRW, Elgin or Crane.

Yes, you'll need one of the retro-roller cam kits for your Mark IX BB.

You have a lot of disharmony in your build which makes recommending a cam difficult; 8.25:1 compression, 3000 stall, 4.20 rear gears, 650 cfm Holley (too small for a 454,..even the factory topped 454's with a bigger 750 cfm Q-Jets in 73), etc.

Any chance a new set of heads are in the budget?

You and I will disagree here. The 750 Q-jet is a very forgiving carb and one of the few 750s that should be on a stock to mild 454. I had a 3310 750 vacuum on it for a while and it ran okay but the 650 HP double pumper absolutely out performed the 750. Killer throttle response with that smaller venturi. Cubic inch plays a part but so does the rpm and head VE. Anything other than a 750 Q-jet would be over-carburetion in this application.

As far as heads, I have three sets laying around. I will be either taking the 781s or the 049s and installing 219 valves along with a little unshrouding and port massaging. Once again.....this did not happen at the ideal time. My upgrade plans were a year or two away. ;)

Agreed you really do not have enough Static Compression to Retro-Fit a Roller Cam. With an 8.5:1 Static, a HFT Cam between 266 to 270H-10 would be appropriate. I would recommend the CCA-924 Springs and buy good HFT lifters like Morels or if you can find them OEM or Old Stock TRW, Elgin or Crane.

You can put a retrofit cam in just about anything. Whether or not it's worth it is in the eyes of the beholder. The 270HR is actaully what I'm looking at. It is a weird combo but I have built it on the cheap. I did the rear end and trans gears knowing that the motor improvements would be next. The car is actually a kick in the pants to drive. It's gutted and light. That stall is like coming out of a slingshot.

The whole point of this car was to build something fun to drive on a budget. I did just that. It runs hard for what it is. Heck....maybe I have more compression than I think. I am excited to think of how good it will run when I finally get the pistons to match the open chambers and really build a good "combo". For now I just need it running again and want to go HR since I can reuse the lifters when the larger cam is needed.

Thanks guys for your imput. Realize that this car is driven about 1/2 miles at a time. It will see maybe 50 miles a year. I just use it to test my Holley carbs I build.

Dubs68,..we agree to disagree on the 650 cfm carb coupled with a healty 454. A final thought though,..Chevy put 780 cfm carbs (Holley VS) on Z-28 302 engines. Were they "over-carbed"? I think a 750 or 800 DP carb is the call here,..the Holley 4780 (800 cfm) would be my call.

Set that aside.

The suggested cams so far are great for the engine's low compression (8.25:1) but not for the drivetrain (3000 stall and 4.20 rear gears).

Again, you have some mismatches. What are your plans and goals for this car? What future upgrades are in the works? Maybe new heads?

Dubs68,..we agree to disagree on the 650 cfm carb coupled with a healty 454. A final thought though,..Chevy put 780 cfm carbs (Holley VS) on Z-28 302 engines. Were they "over-carbed"? I think a 750 or 800 DP carb is the call here,..the Holley 4780 (800 cfm) would be my call.

Set that aside.

The suggested cams so far are great for the engine's low compression (8.25:1) but not for the drivetrain (3000 stall and 4.20 rear gears).

Again, you have some mismatches. What are your plans and goals for this car? What future upgrades are in the works? Maybe new heads?

Good debate Staightline. First of all, where are you getting the "health 454" from? This started out as a low HP high torque motor that barely spins to 5K. The motors you are refering to are big rec headed, high compression motors like the LS5 and what not. That 302 is also a nasty little, high comp good headed motor for it's time.

Realize that when GM contracted Holley to build OE carbs for them, they didn't have the correct carb built for each motor. That's not cost effective. Except for some of the vette and others getting the 600 cfm, if it was performance, it got the 780 because there was nothing else to go with (in most cases). Whether it's a 4555, 4053, 4346, 3247.....etc.....they are all the same 780 main body with the same 1 11/16th throttle bore and the same metering period. That and the Quadrajet for the lower horse motors is all GM had to choose from. That doesn't mean that each motor got the right carb, they just got the best from GMs list of choices.

You take a stock, low comp 454 truck motor, it doesn't need anything over a 650 in almost every case. I run through about 300 Holleys a year and this is real world on the car testing I am speaking from.

Isn't mismatching what old school hot rodding is all about?? It's using what you had laying around. I am excited to know that is it not the ideal combo and that it runs as good as it does. I have another early 454 in the corner of the garage. I will be going .030 over and installing pistons to get me into the 10.5 comp range. I have a gas station near my house that has 110 oct at the pump. Really nice. I'll be cleaning up my 049s and installing bigger valves/port work. I don't have all the specs yet because I'm not there. At that point the stall and gears will match much better but I'm not even in this car 2K. It's a heck of a lot of fun for such a small investment.....that is until the cam went pooh pooh. :mad:

Dubs,

Just because you go to a rollerized set up doesn't mean you won't experience failures with those lifters as well.

I do realize that mechanical failure is mechanical failure. I just believe it to be far less chance with a roller setup. Needle bearings can go bad but we are talking nothing radical or even close. I do understand that it won't eliminate the possibility.

Michael....you need some more cars! lol

some of your problem is the full syn., that oil has no lead in it,royal purple or hot rod oil has the additives in it , full syn., is made for roller cams:yes:

I do realize that mechanical failure is mechanical failure. I just believe it to be far less chance with a roller setup. Needle bearings can go bad but we are talking nothing radical or even close. I do understand that it won't eliminate the possibility.

Michael....you need some more cars! lol

If you only knew Dubs......lol.

sorry about the lead quote it is zinc they use , hope this helps

Dub,
Here is the thread for the budget 396 build for my 68 RagTop
http://www.chevelles.com/forums/showthread.php?t=365833
I'm using what is lying around in the corners of my garage! I'm even going Q-Jet on PP Truck heads!!!

Stock late 70s 454 with 781 or 049s are in the 8.0:1 CR range from the factory.Head shave and a shim head gasket like the Mr Gasket 1131/1131G http://www.summitracing.com/parts/MRG-1131G/Application/?prefilter=1can bring the CR up a bit, every little bit helps here. I took it another step. Three years back, took a $200 1977 virgin short block with a few busted bolts, gave it a "budget" rebuild after the bolt issues were fixed. I used some 1968 063 heads that were in my garage and a .266*/.533"/108 LSA Hyd FT cam, old Eddy C-396QJ intake, and a $100 Holley 800DP off Craigslist. CR was 8.8:1. Within a few outings, I had the 1970 Elky running 12.70s. Simply floored my non-believing pals with this 4000 lb beast with 3.42 gears...very quiet.

just for the record, the Summit 238/248 cam works pretty good in a stock 454...way more cam than you think for a low CR 454. Alas, just another FT cam.


The 68 396 mentioned above is getting a HR cam, 218/224* .510/.510" 110 LSA cam. Local DELTA CAMSHAFT had me get some ELGIN HRs, under $400. Perfect for a mild HR like the one I have or the Gen VI take-out cams many use on the Team Chevelle website. Decent little street cam. The retaining plate feature is great compared to cam buttons, not to meintion the bargain cost. Thing is, if you are going to get really serious down the road, you may wish to pony-up for some rather serious roller lifters initially.
Get with CSTRAUB Chris is the man! He'll get you right.
http://www.straubtechnologies.com/contact-us/

Flat tappet cams are really getting a bad rap. Dubs you said you didn't match the springs to the cam. That's probably why it failed so quickly. Rollers could suffer the same fate if the spring pressures aren't matched to the cam card. I've only ever had one solid FT fail and it was my fault due to springs rates not being matched and set up correctly and lack of zinc in the oil. Not really a mechanical failure, I attributed it to operating outside the limitations the manufacturer recommended. Yes physically I wiped a lobe, but it was no fault of the product. Dave Vizard has written a lot of the FT subject and most of the time it isn't the fault of the camshaft according to him.

Wel DV is the man for one thing. If you read my posts, no where do I blame the manufacturer or the oil. It does have aftermarket springs and the profile was small enough that I doubt that was the ultimate downfall. I've been running a comp 280H with STOCK gm springs for years now with no problems. Not a good idea but I didn't know any better at the time. ;o) Bottom line is that it's a great time to upgrade to a roller and that's what I'm going to do. Will be running the XR270HR with new comp 911 springs. EVERYTHING will be matched this time. I will agree with you that sometimes mechanical failure is assisted by the owners of the mechanical item! lol

Bottom line, set a cam up right. End play, lifter bore clearance, pushrod length, installed height, spring pressure, valve adjustment.

Synthetic oil may have been the problem but some do have the additives needed. Off the shelf stuff doesn't.

Dub,
Here is the thread for the budget 396 build for my 68 RagTop
http://www.chevelles.com/forums/showthread.php?t=365833
I'm using what is lying around in the corners of my garage! I'm even going Q-Jet on PP Truck heads!!!

Stock late 70s 454 with 781 or 049s are in the 8.0:1 CR range from the factory.Head shave and a shim head gasket like the Mr Gasket 1131/1131G http://www.summitracing.com/parts/MRG-1131G/Application/?prefilter=1can bring the CR up a bit, every little bit helps here. I took it another step. Three years back, took a $200 1977 virgin short block with a few busted bolts, gave it a "budget" rebuild after the bolt issues were fixed. I used some 1968 063 heads that were in my garage and a .266*/.533"/108 LSA Hyd FT cam, old Eddy C-396QJ intake, and a $100 Holley 800DP off Craigslist. CR was 8.8:1. Within a few outings, I had the 1970 Elky running 12.70s. Simply floored my non-believing pals with this 4000 lb beast with 3.42 gears...very quiet.

just for the record, the Summit 238/248 cam works pretty good in a stock 454...way more cam than you think for a low CR 454. Alas, just another FT cam.


The 68 396 mentioned above is getting a HR cam, 218/224* .510/.510" 110 LSA cam. Local DELTA CAMSHAFT had me get some ELGIN HRs, under $400. Perfect for a mild HR like the one I have or the Gen VI take-out cams many use on the Team Chevelle website. Decent little street cam. The retaining plate feature is great compared to cam buttons, not to meintion the bargain cost. Thing is, if you are going to get really serious down the road, you may wish to pony-up for some rather serious roller lifters initially.
Get with CSTRAUB Chris is the man! He'll get you right.
http://www.straubtechnologies.com/contact-us/
Yep, runs strong and runs like a Cadillac. No, not an STS.
How's the weather over there George? It finally quit raining here this morning. Then it iced up. Took the dogs for a walk and I stayed on the shoulder of the pavement because it was covered with black ice. You guessed it. One of the pups keyed on one of our many Coyote's scent and I was pulled on my ***. Only sprained an ankle though.:cool:

Yeah I got the 'yoties always in the field across the street. you can see what I do with them.......

I did not exactly match the springs to the cam but I did have aftermarket spring. I broke it in and had additives for awhile then change to full syn. Not sure if that was the part that screwed up on. It's the 2nd BBC lobe I have lost in my lifetime. I don't know if I will know for sure but I'm not giving it another chance. From now on I will "roll on"!


Well BBC's are known to be tough on cams. You didn't help matters at all with not running the correct springs and made that even worse by not running the correct oil. Your cam had no chance at all to live.

If this is the second cam in the same block, you may want to consider having your lifter bores checked. If they are worn you can kill a roller lifter/cam too. Also BBC's are known not to have the lifter bores at the correct angle, which is why many guys have bushings installed and indexed.

I just thought I'd update this thread and have a little fun with straight-line.

This is what disharmony looks like. I was finally able to get the valve train correctly installed and the geometry dialed in. Went with the Comp 270HR with 270/276 dur and .51 lift. The car flat gets in. After I got it straightened out, I got back into it and blew the tires up again. If this is disharmony....and it just might be........I can't imagine what my next motor will run like with about 3 more pts of compression and everything to match.

Sorry for the dirty windshield. I just pulled it out of the shop.

http://youtu.be/Q56GHXjgGgM