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Just wiped a lobe. Wanna try a non-thumpr now. Any suggestions so I don't lose power?

6K views 26 replies 10 participants last post by  Northern Chevy 
#1 ·
Basically, I had the hydraulic flat tappet thumpr cam. (smallest, not mutha, etc.) Here are the specs for it.

What should I look for in a non-thumpr cam to offer close to equal power as what I have now? Just make sure it has the same lift duration?

FYI It's a 350 sbc basically stock but with upgraded aluminium heads, edelbrock air gap intake, and holley 650 dp.
 
#6 ·
Yes. Noticed a ticking and saw that one rocker wasn't moving as far as the rest. Pulled the lifter out and it was beat to hell and domed. Looked down at the cam and that lob was basically gone.

Thanks for the good suggestions, guys. All I want is a cam that will (at least) match the power that I got from the thumpr, but without the whole "give up driveability for a cool sound" aspect.
 
#3 ·
110941-11 CL110941-11 279 279 225 225 .465 .465 111 108 Hyd. Hyd. 1
1500-5600 Fair idle, Strong mid-range performance.
or step up to

113215-10 CL113215-10 270 278 217 225 .495 .500 110 106 Hyd. Hyd. 1,2
1300-5500 Good idle, Street Performance. Strong lower mid range. Stock converter OK.
depends on money
second choice here would be nice and idle better,but make more power
 
#4 ·
Thats what I keep fearing although maybe unfounded but to have a wreck with a flat tappet cam rather then going the roller way. I assume you've been looking in the Comp catalog online and go to page 170 where it mentions getting a cam nitrided which will hopefully help with a cam starting the wear process and wiping a lobe. Worth asking about anyway.
 
#7 ·
It's prolly gonna be more about what oil and additives you're using than just replacing the cam. If you don't have enough zinc, ZDDP, phosphorus, etc in your oil, the new cam will meet the same fate as the current one.

Russ
 
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#25 ·
For those that are very familiar with quality roller lifters vs what I imagine are ones a guy should stay away from, what brands would be suggested in ether a retro fit roller rebuild or a roller ready block. As 33Willys77 mentioned before, he had a retrofit roller adjoining bar fail and cause major damage.

Put another way, what brand of cam ( and billet or not ? ) and type of retro fit rollers should Zerocyde have used if he had decided to tear down his engine and start from scratch.
 
#26 ·
Correction, mine were not retro fit, they were aged - rollers were good, but the connector between the lifters fatigued out. I dont know how old they were - could be from the 70's. It was not a bar, more like a peice of sprung (tin like) arched tab. Not like what they are today. I was just saying, I had a mishap and all that metal was all over the engine. I could see it in the pump and in the bearings.
 
#27 ·
Oh ok sorry, that was my mistake for visualizing a newer style retro fit unit with the link bar arrangement. As to it causing metal fragments to bypass the filter and get back into the bearings, never mind the oil pump that WILL suck in everything on the bottom of the pan and damage itself, I can see some horrible visuals of what a cam failure would cause. Thats good to know as I've had friends who did the same thing, had a cam lobe get wiped and just slipped in a new cam and lifters without tearing into the engine further and "hope" for the best. That would be like sitting on a bomb that never went off ... yet !.
 
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