New heads on an old block

Question for you guys with way more smallblock Chevy history than me;

The motor in my car is "OK", with some minor odd issues and it just doesn't run like I remember these cars from the '90's. 165k miles. Big issues I see are a somewhat weak #7 cylinder and oil fouling all around.

Given these motors seem to be pretty reliable, and that the problems I see are more likely in the top than the bottom, would it be silly to put new heads on this motor and "call it good"?

I figure if the problem does end up being in the bottom, I could always pick up a short block and swap the heads over, so it's not really a "loss".

There's also a guy not too far from me on Craigslist offering a 96k mile motor and trans from a 96 Caprice for $750, which may be something to consider.

it's unlikely your heads themselves are bad, so I'd say it's probably a waste of money. You can do valvesprings and valve stem seals though. put the money you'd otherwise have spent on heads on some 1.6 roller rockers and you'll gain about 10 hp.

a somewhat weak #7,... oil fouling all around,..


I,ve had numerous lt1's,.they don't burn oil much ,.except when the intake manifold is leaking,..

They are usually a very strong reliable engine,..165k is not high miles for an lt1,.

Have you had the rocker covers off?

Jason - yes I agree the oil fouling is most likely due to bad stem seals. Why springs though?

Nick - Yes I did have the rocker covers off when I changed the leaky valve cover gaskets. I also did change the intake manifold gasket, so I don't think I have any leaks there.

The weak #7 does bother me a bit. I always thought that it either meant a leaky valve seat, bad head gasket, or worn rings. Are there other things that may be to blame?

I wanted to also mention, I feel more confident in my ability to swap the heads than I do replacing the stem seals and/or springs with it still on the motor. I've done head replacements before, and the motor still ran afterwards.

lamune wrote:

The weak #7 does bother me a bit. I always thought that it either meant a leaky valve seat, bad head gasket, or worn rings. Are there other things that may be to blame?

Those three are the most likely reasons,. reasons not so common:-.. bad cam lobe, bent pushrod, valve lash way too tight,.pcv system not functioning properly,.
How weak is 7?

lamoone wrote:

I wanted to also mention, I feel more confident in my ability to swap the heads than I do replacing the stem seals and/or springs with it still on the motor. I've done head replacements before, and the motor still ran afterwards.

I have read some of your adventures repairing stuff,. so i understand your lack of confidence,.
but,.......... it really is a simple job,.

Here's my method,. pull covers, pull the rockers, (count exactly the number of turns to remove the nut) use a nice long skinny screw driver put it in the plug hole, turn the motor till you figure the piston is down a ways.
remove the screwdriver and feed in some skinny nylon rope till it won't take any more easily, roll the motor over moving the piston back up till the motor stops moving, all the string is now packed in the combustion chamber, take a deep socket about 2/3 the diameter of the spring retainer, place it on top of the retainer and give it a real smart couple of whacks with a 2lb'er, (an extension makes it easier on the thumb)
then use your home made valve spring compressor to push the retainer down and remove the locks then release the spring pressure, remove it all,.peel the old seal off,. push on the new seal (i use old style umbrella seals they work just fine) re-assemble squash the spring pop in the locks,.(a nice magnetic screw driver helps or a blob of grease on your finger tip) use your socket and extension again and give it another couple of light taps to seat the locks nicely,.. do the other valve, roll the piston back down, replace the rockers screw the nuts back down the exact amount of turns (usually within 1/8 turn will be just fine) pull the string, bolt in the plug and wire, repeat 7 more times,.
There are a few write ups on this including pics of how to make all kinds of spring compressors out of bar stock,.number 8 hole is a pita ,.. more so when installing heavier springs for the cam swaps,.

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Nick, this is brilliant. I like this a lot more than the compressed air method.

The inside of that head is a lot cleaner than mine!

I think it may also be a good excuse to change the springs as Jason suggests. And maybe roller rockers

Would you guys like to recommend a good set of valve springs? How are the Proform (#66929) rockers?