The Official H-Body Internet Community

My stock flat tappet 305 Monza has 62k ish miles. Took the intake off and inspected the lifters. 15 look reasonable. 1 is worn down in the center. Noticable to the eye. Should i just clean and reinstall or buy one new lifter and hope for the best? Good compression on all cylinders. Thanks

There were some bad cam issues in that period. You may get by for a while with one new lifter but chances are the lobe is already bad. best option is a new cam and lifters.
Flat tappet cams need zinc in the oil which must now be added separately.
Motor oils used to contain zinc but as roller cams and catalytic converters took over they quietly removed the zinc.

Thanks, that is what I am learning. Engine has 62k. Hoping the cam bearings can handle a new stock cam and lifters. Will need to pull the motor but then I get to clean things up and check the lower end and sealing.

I'm late to the party here, but Smiley is spot on with his advice. If the lifter is worn, so is the cam. Replacing one bad lifter could get you by for the short term, but will need to be adjusted frequently as it and the cam continue to wear. And as they wear, they will be putting metal shavings through the rest of the engine, accelerating damage everywhere. If it's an intake lobe, the engine will slowly lose power, but if it's an exhaust lobe, if it completely goes away, it will produce a nasty backfile through the carb.
Back in the day, we used to joke about 305's having "wooden camshafts". lol. A lot of failures due to many factors, including the aforementioned removal of Zinc from engine oil, poor quality castings and sloppy maintenance schedules(infrequent oil changes).

I had heard these things which is why I pulled the lifters. Not bad considering age and 62k. I am hoping to find a stock spec cam and new lifters. I will install on original cam bearings and hope for the best. If/when it goes sideways in the future I can pop in a crate 350. I like that it is a numbers matching V8 car right now.

The cam bearings should be ok, usually you can change a cam in the car.

Cam technology has advanced so far since your car was built, there are many cams out there that will offer better performance and better fuel mileage while not sacrificing any driveability. Hunting for a stock camshaft seems like a fruitless task.
Roy

Thanks for the help, trying to keep the car stock as possible with a nice idle. The 305 puts out enough power for me. I am a Vega 140 guy so I am already happy.

My '77 Ventura's cam went at 30K miles [305 2bbl.] I replaced it with a "Stock Replacement" cam kit that every parts house used to have on the shelf back then [mid '80's] I also changed to a Q'Jet with all stock parts [there was a lot of "Noise" about upcoming e-tests that didn't come for ~15 years]. The outcome of that would definitely put me with Roy there, [much livelier] you could find a cam with the same duration and lift, but with a different profile that will give you more power and no down sides, check the catalogues you will find something to make you happy. For stock appearing, swap out to the truck intake and carb, Rochester's cams came to 500CFM IIRC and ours are about ~350CFM, will look factory because it is, just the truck factory, roadside compliance enforcement shouldn't give you any grief either, as again all factory, if that is a concern where you are, it is becoming so here. Keep us posted Please! Harry

Cam design & technology has come a long way since the 1970's. Back then the manufacturers were scrambling to meet emission standards, and the easy way was with a very mild camshaft profile. The aftermarket has found ways to keep the emissions in check, AND make more power without sacrificing idle quality and driveability. Here's a cam that is 50-state legal as far as emissions go, but will wake up that 305 a whole bunch. If you're worried about it not being "original", just tell everyone it's a stock replacement cam. Nobody here will tattle.......
http://www.compperformancegroupstores.c ... Code=HFTPE

I am a concours level judge for many different clubs/organizations. I will tell you that NO judge will EVER ask you to open your engine so THEY can look at your cam. Put in what you want!

Filled out the comp cam questionaire and they suggested the same 246pe cam. My concerns are smooth idle and enough vacuum for the power brakes. Also, I assume this higher profile cam will need different/stronger valve springs and might increase wear on already dodgy design flat tappet cam/lifters

New springs are always a good idea when replacing a cam. The stock springs that are in there now are no doubt "tired" from almost 40 years of service, plus a new set designed to match the cam will give you some more RPM to play with. I don't exactly remember the redline on the tack in those 305's, but it was somewhere less than 5000 RPM. After the new valvetrain parts, it should be good to 6000.

I dont believe that camshaft would give you any concern regarding increased wear. It is mild, mild, mild. Unless you plan on driving your Monza another 100 plus thousand miles, you wont ever have to service it after installing it, and it should give you everything you want and more. Trust the Crowd.
Roy

Don't forget to use the assembly lube recommended by the manufacturer when installing the cam and lifters and use break in oil otherwise your new cam and lifters will be toast. Modern engines have roller lifters with less friction therefore most engine oils will not have the required additives.

https://www.summitracing.com/search/pro ... -motor-oil