L81 camshaft

[429bbf]

gentalmen i have a slight miss or popping sound in my wifes car. its a 1981 corvette with anL81.i thought it was a carb problem so i bought and installed a hp kit from cliff .the car car only has 19,000 miles and has always been kept inside. it just doesnt get driven much.iv checked about everything i can think of and was wondering if the 81 had the cam problems like gm had in the late 70;s.the popping is coming out the top of the carb when you flop the throttle wide open. the tps and the fuel mixture solenoid work properly.it act like its ether got a flat lobe or a sticky valve. any ideas would be welcome. thanks in advance dean

[Schurkey]

Or a leaking intake valve.

How does it leakdown test?

[429bbf]

thanks for the reply i havent done a leakdown test or pulled the valve cover.the thing is a p.i.t.a. to work on.i took it to my buddy place he has all the old sun machines and a million other auto diagnostic tools and he knows how to use them. we checked all the sensors, wires, plugs .timing and anything else we could think of.we think its either a sticky lifter or valve as you suggested.you would think that with so few miles this thing would still run like a top.ive.owed it since 1982 and it had 1000.miles on when i bought it.and has always run good.until now.dean

[Cliff Ruggles]

Do a compression test, it will find the problem cylinder.  Most like a lobe is gone off the camshaft.  Unlikely it's got a "sticking valve", the piston would smack the valve and bend it....Cliff

[429bbf]

im looking for advice on what cam to install.i dont want to make any major changes . i just want a good cam that works with the stock electronic carb. im not making a hot rod.i want my milage and power back that it had.i only want to do the job once .id like to here from someone thats put one in and how it turned out.thanks in advance. dean

[Cliff Ruggles]

I'd look at the stock replacement cam for the 300hp 350 engines.  They should be available at NAPA, or most other auto parts stores, as a kit with the lifters.  I'm not a big fan of aftermarket cams with short seat timing events and fancy "modern" lobes.  I've used the factory cam many times over the years in near stock 327 and 350 engines.  They idle with plenty of vacuum, strong power over a broad rpm range, and good fuel economy.  They computer will be happy as well.....Cliff

[429bbf]

thanks cliff . went to napa he showed 2 cams a  cs274 which is a oem replacement and an edelbrock 2102 i think. im not interested in either. im thinking of useing a isky 262. its got a little more duration and about the same lift.im wondering if anybody has tried one of these and what the results have been.thanks in advance. dean

[billy 2]

I have used the 274 camshaft in many of the small block Chevy rebuilds over the years.  I always had great success with them, good idle characteristics, reasonable power.  Just all round good replacement camshaft for a small block Chevy.  And, as Cliff said, your problem might be a flat lobe on the cam.  This can easily happen with today's oil and the lack of the ZDDP additive.  billy2

[429bbf]

thanks billy, after looking at the cam grinds it looks like the oem for the l81 is the same as the 300 hp l48 .and the 274 is that cam so i think ill use it .i respect peoples opinions that have tried the product and not read it in a book and they say it works.theres a lot of GM folks on this site with a lot of knowledge.iv never overhauled a gm.done a number of fords. i work on heavy equip. every day the biggest stuff in the world.and quadrajets for a hobby.dean

[429bbf]

cliff i didnt understand what you were saying at first but i should have . ford did the same thing on the 385 series they used the same grind cam on the 1968 429 as they did the 1983 460. all they did was change block height, heads.pistons and timing gears.and about 200hp.dean

[Cliff Ruggles]

I've used the cs274 cam in several engines in vehicles I've owned here, you will not be disappointed in it.  It will provided good idle/off idle power, and a broad power curve.

My 1967 Impala SS used one in the 327 build I did for it.  With 3.31 gears and 4L60 OD trans, it knocked down 18mpg's average, getting up near 25mpg's on the highway.  PLENTY of power from idle to whenever you decided to shift it......Cliff