The block is a stock rebuild of a late 70's-early 80's 350; 2 bolt main, 8.5:1, rated 265 hp, aluminum pistons, stock rebuilt c.i. heads, Edel. performer w/Edel. 600cfm, Summitt copy of GM HEI dist, reportedly (by mechanic who did install) has 'truck or rv cam', hydr. lifters, Hedman elites, 2.5" exhaust, Fluidamper 'streetdamper' small balancer. Replaced stock rad. w/Howe alum. 2row w/tranny coooler and runs 165-185 any weather. No AC installed currently, 700R4, 3.36 Eaton posi. Haven't noticed any loss in off-the-line torgue or high end. Have only noticed it takes a little longer to get to 75-80mph, but timing hasn't been checked in about 16000mi. Changed plugs about 6000mi ago-same .035 gap. Always use 87% Octane-UL.
Has had one major problem since new- was burning about 1.5 qts/3000mi.- mechanic replaced valve stem seals, at 25000mi- now down to 1 qt./3000mi- still seems high to me.
I guess that spells the profile out.

Now the actual problem: Tapping noise coming from heads/valve covers- increases with rpm until it probably gets blurred by high rpm engine noise. Seemed to originate on one side only, could be my imagination, but now seems to emanate equally from either bank and, if I had to guess, from one hole on each bank.
Sounds somewhat lower in pitch than tapping from header manifold leak- had a few of those,but no longer since using Earls header gaskets (eventhough Hedman says to only use theirs) and checking torque on header bolts about every 15000mi.

Mechanic tells me it could be anything from a burned valve seat to a worn cam lobe.

If it is a burned seat, and given that the heads req. r&r, should I do a complete head re-build with the best stock parts- I have a feeling the rebuild didn't necessarily use top end parts since the 1st failure was valve stem seals. Also, I'm not after torque and hp as much as a smooth, quiet and most fuel efficient SB (from a carbuerated sys.) for across the street-hwy range.

If it's a cam failure, should I replace with the Edel. cam kit counterpart to the Performer 2101 (non-egr) or would slightly more agressive cam (Edel. or other brand that matches up with present config.) help acheieve effeciency for such a small hp-output unit?

I know, lots of questions in one post- I'm just hunting for the major worst case and options to get rid of tapping noise (I always prep for worst case scenario)- then again, it may just need a thorough valve train adjust and timing re-set?

Appreciate any suggestions or comments. Thanks.

I would pull a valve cover and check, it might
be a rocker arm lock nut that has backed off.
You could do a compression test also.
Good luck in finding your tap.

If it's a burn or cracked valve a vacuum check will tell. It sounds like loose rockers..hopefully.

Well, the internal combustion gods were smiling on me; turned out to be valves, rockers needed adjustment. Not touched since new.
Now exhibits smoother idle, veery smooth launch, and slightly better mpg., oh yeah, quiet too. :D

My power curve from 2nd to OD. is still too long; takes a good 7-10 sec's (depending on how much fuel I pour) to get from 40-80mph (on-ramp to #1 lane). I think my 700r4/3.36 re. needs to go to a 3.55- that extra rpm would probably make a little shorter power curve. I am also considering switching from the 60x15 to a 65x15 tire
series; I also like the extra ground clearance.


If I were to do it all over again, which I'm certain, if not with this car, then another, I would look for at least a 300hp 350 (not sure of Vortec technology)w/Fuel Injection. Sure, I'd give up the simplicity of a carbeurated fuel supply, but then it's not that simple anyway. By that I mean as it is I'm not inclined to want to do much more to my carb than check idle, choke and linkage wear. Aside from that, I leave it to a capable/reputable mechanic.
The difference would be that when something's going south on a carb system, you can usually see or smell or hear it right up front. With FI, it seems like another branch of mechanical systems to pour over just to recognize the various components.
On the other hand, from what I can tell, the launch, rate of acceleration when already at a given speed and fuel efficiency all are noticeably improved by FI.
Now, what are your opinions of all this. :confused:

My '72 El Camino 350/350 is built very much like yours. Just to compare, the way yours is running
(speed curve description) sounds like mine on 87 octane. According to the manual the minimum recommended was 93. Mine runs decently on 89 which I use most of the time, if I want that extra bit of power I use 92.It definitely makes a difference. By the way, I get 12-13 mpg around town, actually got 20 on a recent long trip.