Olds 350 Knock Series

[g0thiac]

Thanks to your advice guys.

I had figured out that the engine knocking was in fact, happening under the drivers side valve covers, on cylinder 3.

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After removing the rocker arms and pivots, I first noticed two things.

1. The valve springs on cylinder 7... were JB WELDED. Why someone, would spend all this time, restoring this vehicle just to not do the thermostat housing RTV properly, and this but will paint, rewire and tap the water pump and block for sensors, to add aftermarket gauges.

Makes ZERO sense in my opinion 🤦‍♀️🤣🤣🤣

2... And the boss for the push rods was covered in carbon, as one might expect on an engine this old.

But then- after using my finger I realized the huge, and I mean MASSIVE f u c k i n g hole 🤣🤣🤣🤷‍♀️ which also explains why the push rods, despite by some actual miracle not bent in half- were work down.

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[olds307 and 403]

Sounds like some awesome work done. The 3A heads live up to their reputation.

 

[g0thiac]

Well since I got new rocker arms and pivots-I decided to go ahead and install them regardless.

For cylinder #3, I also chose to replace the push rods. I noticed that one slightly pokes out more than the other.

It also seems to pump up oil faster than the rest of them, so I am wondering if this might be a lifter issue.

 

[g0thiac]

And here are the results.

Despite the head having the cracks and giant hole also- I am still really shocked, for working on my first valve train doing the rocker arm and pivots made it run alot better, even if the knock is still there too hahaha 🤷‍♀️🤣🤣🤣

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[g0thiac]

So basically, I know I don't want to rebuild the entire motor, as the older castings didn't crack as bad and to me if, I am wanting to pull the whole engine it might as well, have something worth the time and money spent also!

So I have decided on doing two things.

1. I am going to pull the intake, and see if there is any metal fragments left of the push rod boss.

2. If there is more damage past that, I will be swapping the heads.

I can get 403 ones here for cheap, and while I understand 350 is better, this is just to keep the vehicle going, until a better block is in there 😎💪💪💪

Can I install those? Not thinking of performance at all, strictly just want to know for bolting and thats it haha 😤😂😂😂

 

[olds307 and 403]

The 403 heads have chambers 10cc larger and don't flow any better than stock 3A, exhaust side especially. My 4A measured 86cc+, so probably 7.3 to 1 is where you will end up. Also make sure a 350 head gasket will seal properly if you pick them up. I might have one 4A head sitting on my engine stand for weight, I can check, have multiple 350 head gaskets. A set of early 307 heads would also bolt right on and even with thicker Felpro head gaskets maintain 8.5 to 1. Hopefully the 4A heads are nearly free. Yeah, new rocker arms make a big difference on non adjustable valve trains. Good luck.

 

[g0thiac]

The 403 heads have chambers 10cc larger and don't flow any better than stock 3A, exhaust side especially. My 4A measured 86cc+, so probably 7.3 to 1 is where you will end up. Also make sure a 350 head gasket will seal properly if you pick them up. I might have one 4A head sitting on my engine stand for weight, I can check, have multiple 350 head gaskets. A set of early 307 heads would also bolt right on and even with thicker Felpro head gaskets maintain 8.5 to 1. Hopefully the 4A heads are nearly free. Yeah, new rocker arms make a big difference on non adjustable valve trains. Good luck.

For sure, I figure for now it will at least keep things running until I get enough for an older 350 blocks.

And yeah I will haha, I will make sure to get the gasket and RTV proper here for sure.

But yes, they are crack free and $50, locally which is surprising so I definitely am not losing money here.

And thank you for the advice, like to know about non adjustable valve train here, this was the first time I have ever done rebuilding for the top end of any engine so lol 🤷‍♀️🤣🤣🤣

 

[g0thiac]

The 403 heads have chambers 10cc larger and don't flow any better than stock 3A, exhaust side especially. My 4A measured 86cc+, so probably 7.3 to 1 is where you will end up. Also make sure a 350 head gasket will seal properly if you pick them up. I might have one 4A head sitting on my engine stand for weight, I can check, have multiple 350 head gaskets. A set of early 307 heads would also bolt right on and even with thicker Felpro head gaskets maintain 8.5 to 1. Hopefully the 4A heads are nearly free. Yeah, new rocker arms make a big difference on non adjustable valve trains. Good luck.

Now that we are on that, let’s talk CR right now.

Would it make sense, if the engine is already damaged at this time to have it lowered, would that be beneficial from not performance, but extending the life rather?

Otherwise, I can do 307 also. Just trying to keep things simple and cheap haha 😂💪

 

[olds307 and 403]

Yeah, for $50 and one point of compression loss won't hurt, as you said, might keep it alive. Just get aggressive with the timing, low compression Olds love a lot of part throttle timing. I will put a Felpro on my 4A and put a pic up here this weekend.