Thread: Sbc 327 - Need Help Big Time!!!

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I recently purchased a 1966 Chevelle Malibu with a SBC 327. It has the 461 cast camel hump heads. Here's what I was advised to buy: Comp Cams 292H (kit), Holly 750 carb, Hooker Competition Headers, Edelbrock Performer RPM intake, Flowmaster cans, and a couple of other knick-knacks. Here's the issue: I just got the whole thing back together and (I believe) wiped three lobes off the cam!!! I REALLY need some help/advice before laying out any more cash... Anybody have any expertise on this issue???

What break in procedure did you use on the cam???

hydraulic flat-tappet lifters (comp cams), engine leak-down (pre-install) less than 3% on any cylinder. Has a Powerglide 2-speed with fairly low gears (probably 308's). Have custom torque converter on order with 2500 stall. Not sure of piston compression rating - guessing 10.5:1.

Was advised to use (red) break-in lube and run at approximately 1800 - 2000 rpm for 15 minutes... with reduced cooling system pressure.
Is it common for a cam to do this at break-in? Or did I screw something up royal?
I AM NOT 'the man' when it comes to this stuff - I'm a greenhorn for the most part.

Did you have the valves adjusted correctly, was the timing set right? Did anything break, pushrods, etc. or just wipe out the lobes on the cam???? New cam and new lifters????

I'm almost certain the valves were adjusted correctly. Followed instruction to the letter... tightened until pushrod barely moved by hand (at right time and stroke) - then tightened 1/4 turn. Not sure if anything bent/broke yet - too depressed to open the motor again right away. Installed all new parts. My "advisors" all run super high end 1/4 mile race motors - all solid lift not hydraulic so not sure if that played into it. Three intake valves (judging by rockers) not moving so assuming wiped lobes off of cam...
Cam timing was set "dot to dot" and then at 30 degree mark on balancer pulley.

Hard to say till you get the intake off.... Post us some pics of the wounded cam if you can.....

I plan to remove the motor this Saturday and get it on a run-stand and tear the whole thing apart. I'm assuming I've got trash down in the block now and need to check the rotating assembly (which was perfect before). The main question is: Is this crap going to happen again if I use a flat-tappet lifter set again? If it's a strong possibility, then I'll invest in a roller cam (thinking XR270 series w/ 495/502 lift) and hydraulic roller lifters. What do you think?

I'll definitely post pics of the damage and see what you all think...

I probably deserved what I got... considering I've molested a virgin numbers-matching motor on a '66 Chevelle! I guess when you throttle your virgin like it's dollar night at the chicken ranch there's going to be some wreckage...

OR - since I'm already in there, should I just go 383? What would it require? 400 crank and 350 rods (bore doesn't change from the 327 to 350 - right?)? Would the cylinder skirts have to be milled for the new stroke? Would my cam/carb/intake still be a good combination?

Nothing wrong with stroking it. Everything will work. You'll need crank, rods, and pistons.


Followed instruction to the letter... tightened until pushrod barely moved by hand (at right time and stroke) - then tightened 1/4 turn.

I have a bad feeling this is where things went bad. You must have a good feel for this. You don't tighten until the pushrod barely moves, you tighten the rocker very slowly while spinning the pushrod until you feel a slight, VERY SLIGHT, drag on the pushrod. (All you're doing is taking the slack out of the valve train) Then tighten another 1/4-1/2 turn. (Lifter pre-load)

I'm thinking you nearly bottomed out the lifter plunger and then went another 1/4 turn.

Originally Posted by camaro_fever68

Nothing wrong with stroking it. Everything will work. You'll need crank, rods, and pistons.


Followed instruction to the letter... tightened until pushrod barely moved by hand (at right time and stroke) - then tightened 1/4 turn.

I have a bad feeling this is where things went bad. You must have a good feel for this. You don't tighten until the pushrod barely moves, you tighten the rocker very slowly while spinning the pushrod until you feel a slight, VERY SLIGHT, drag on the pushrod. (All you're doing is taking the slack out of the valve train) Then tighten another 1/4-1/2 turn. (Lifter pre-load)

I'm thinking you nearly bottomed out the lifter plunger and then went another 1/4 turn.

Read very carefully what Ray as written.
This is very important.
Part of the problem can be pointed directly at the EPA they have taken out zinc out of the oil which does not help.
I am a very firm believer in using a cam lube that has Moly-Sulphide.
I don't know what Comp. cam uses.
I do know that both Crane cams and Isky have a paste that contains Moly-Sulphide.
I will use either one.
Also get with your engine builder/ machinst and make sure you have the correct valve springs for your application.
Above all don't give up.

f*&k the epa

Originally Posted by gassersrule_196

f*&k the epa

I just can't believe you said that being from Washington state.

I'm bettin' on the valve springs. If you used stiffer than stock springs, that's what fragged the cam. You have to assemble the motor with some old, worn out stock springs to break-in the cam, then change them out to the springs recommended by the cam grinder after break-in.

Originally Posted by erik erikson

I just can't believe you said that being from Washington state.