Back in the late '70s/early '80s, Chevy had a HUGE problem with the cams on small blocks. In the end, it was determines the cam lobes were never hardened properly from the supplier. I can't even begin to remember how many cams I swapped on '78-'79 cars back then, some with as few as 20,000 miles.
Going from memory, GM's recommendation(for the dealers) was to change the cam/lifters, flush the oil, change oil & filter. Run engine to break in cam, then change oil/filter again. Run engine another 30 minutes or so, then another oil/filter change. I doubt you have any other related damage to the engine, but you can make a decision on if you want to go any deeper once you get the oil pan off.
Be SURE when you do change the cam that it comes with a bottle of break-in lube. It should, but if it does not, GET SOME! Follow the manufacturer's break-in procedure to the letter. If the engine doesn't start right up after the cam change, don't keep cranking it...find out WHY it won't start.


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Joel Adams
C3VR Lifetime Member #56    
My Link


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"Money can't buy happiness -- but somehow it's more comforting to cry in a CORVETTE than in a Kia"

I just ordered a cam from Edelbrock that matches the performer intake I have, Cam number 2117. It'll be here in 5 days or so. Meanwhile I just moved the car outside and degreased the underside of the engine, tranny and the front. Its much cleaner now and will be easier to work with. I am getting a new pan since the old one is beat up and I am going to go with a new oil pump.

|UPDATED|3/24/2016 7:06:31 AM (AZT)|/UPDATED|


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Daytona Yellow '75 350 Muncie 4 spd

Mine too!


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  + on the F4 Phantom



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So I finally got the cam, took a couple days. This is a stock type hydraulic with more lift and duration than factory. I am going to replace the timing chain and was considering whether to go with a timing chain setup or a gear drive setup. I'm fine with the gear noise and I know they're noisier.. in a good way than a  timing chain.

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Daytona Yellow '75 350 Muncie 4 spd

To be honest, gear drives are no good for anything other than making noise to impress someone. The only REAL, quality set-up that actually improves anything is the single idler types that require a special timing cover, and are a pita to do correctly, or the sets that have only the two gears, where the cam gear meshes directly with the crank gear. The floating, dual idler set-ups are not reliable, and usually create timing issues.
Imho, I'd stay with the tried & true Cloyes double roller chain/gear set. 

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Joel Adams
C3VR Lifetime Member #56    
My Link


(click for Texas-sized view!)             NCRS

"Money can't buy happiness -- but somehow it's more comforting to cry in a CORVETTE than in a Kia"

You're right, had to entertain the option tho. I ended up with the Cloyes double roller and a new timing chain cover. I have all the parts and will have it running this weekend. Can't wait. 

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Daytona Yellow '75 350 Muncie 4 spd

Had a gear drive in my engine for awhile, got tired of people telling me my power steering pumpwas bad. I still have it, Pete Jackson.

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DanT

So I got the Cam/Lifters and heads installed and the motor is back together. Started on first try. When I pulled the pan I did not remove the starter, I just removed all the bolts for the inspection cover so I could get the pan down. That left the inspection cover hanging while I cleaned the pan and installed the cam, etc.. When I was rolling the motor over while adjusting the valves I could hear what I thought was the flywheel rubbing against that dangling inspection plate. Nothing major since I was manually rolling the motor over and I figured that would be gone once I buttoned up the oil pan and reinstalled the inspection cover bolts. 

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Daytona Yellow '75 350 Muncie 4 spd

Found the problem. When I tried to cut some time by leaving the starter in and the inspection plate hanging I bent the inside flange on the inspection plate when I was adjusting the valves. When I bolted the plate back on it allowed the crank flange to hit the bent part of the inspection plate creating that terrible noise. Pulled it apart, cleaned and repaired and painted the inspection plate and I'm done except for the hood. Just ran the cam in at 2k rpm for 20 minutes and then put 150 miles on the new cam at highway speeds. Great to be back on the road. Also the borgeson upgrade is worth every penny spent. @f4gary I have reconsidered the roller cam and would def spend the extra cash for the sake of breakin worries. I used a ton of assembly lube and breakin lube as well as Chevys OES supplement recommended by edelbrock. Fingers crossed. It's done right. Take care and thanks Pat

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Daytona Yellow '75 350 Muncie 4 spd

apesa63:  I enjoyed reading your account of diagnosing and rebuilding your engine. Glad you are rock'n and roll'in again!  Thanks for sharing with us.