350 oiling system modifications

jhodgson

New member
I am beginning to build another 350. This time, since I have a well equipped machine shop in my garage, I am doing the block prep myself. I have a couple of questions. Most of the published advice says to open the main bearing feeds to 5/16" on numbers 2, 3 and 4. Does anybody know why not 5? Some folks recommend using the TAperformance grooved number one cam bearing as well as bridging the lifter galleys at the rear of the block. Others say bridging the galleys should not be part of any performance rebuild. Does anybody know what the ins and outs are around this issue? Just for info, I set the block upside down on my Bridgeport mill to open up the main bearing feeds as well as the suction line hole. I nodded the head 18 1/2 degrees and that seemed to work well for both.
 
I have not built a 350, but I have done a quite a few 400/430/455s. I don't think bridging the lifter galleries is needed. I understand the why and in some applications it might be nice. I have considered trying it for the experience, but so far. have not.
It will be interesting to hear why not to enlarge #5
With the BBs, you are grooving behind the front cam bearing to ensure oil flow from one lifter gallery to the other. This is also one of the reasons you tie the two galleries together at the back of the block. If the TA grooved cam bearing helps to ensure oil transfer past the cam to the second gallery, I would use it.
TA grooved cam bearing description, Click Here...
As they mention in the description, the grooved bearing in other locations allows you to put the oil holes where ever you want. Optimum location for a cam bearing oil hole is between 2-4 o'clock, closer to 4 being preferred. Too far before this allows too much oil to escape before the cam/bearing pinch. Too far past means the pinch is cutting off oil flow to much between the bearing and the cam.
If you are just rebuilding a stock motor, I wouldn't worry about it too much, but if you are performance building, or installing a performance cam, I would feel good about using the TA grooved bearings.
 

jhodgson

New member
I have not built a 350, but I have done a quite a few 400/430/455s. I don't think bridging the lifter galleries is needed. I understand the why and in some applications it might be nice. I have considered trying it for the experience, but so far. have not.
It will be interesting to hear why not to enlarge #5
With the BBs, you are grooving behind the front cam bearing to ensure oil flow from one lifter gallery to the other. This is also one of the reasons you tie the two galleries together at the back of the block. If the TA grooved cam bearing helps to ensure oil transfer past the cam to the second gallery, I would use it.
TA grooved cam bearing description, Click Here...
As they mention in the description, the grooved bearing in other locations allows you to put the oil holes where ever you want. Optimum location for a cam bearing oil hole is between 2-4 o'clock, closer to 4 being preferred. Too far before this allows too much oil to escape before the cam/bearing pinch. Too far past means the pinch is cutting off oil flow to much between the bearing and the cam.
If you are just rebuilding a stock motor, I wouldn't worry about it too much, but if you are performance building, or installing a performance cam, I would feel good about using the TA grooved bearings.
I agree with your cam bearing assessment. For me TA grooved bearings are a given. And like you I am curious about the #5 main feed. This will be another street/strip engine, so I’d rather make unnecessary modifications now than wish I had later.
 

jhodgson

New member
I may have just answered my own question. The feed to the #1 main is already 7/16" so there is no need to change it. #2, 3 & 4 are 9/32" which I opened up to 5/16". Number 1 feeds one rod bearing. 2, 3, and 4 feed 2 rod bearings each. Number 5 feeds only one rod so I'm assuming since it feeds only one rod there is less of an oil requirement and therefore it can stay at 9/32" I'm going to spot face the block at the rear lifter galleys and use Banjo fittings with 3/8 compression steel lines between them. It looks like I'll have to re-tap the galleys to accept 3/8" BSPT like a brake line and that should be about it.
 

LARRY70GS

Active member
The TA grooved front bearing makes bridging the galleries together unnecessary.

I believe the 350 oil mods are pretty much the same as it's bigger brother, read through this thread,

 

jhodgson

New member
Thanks Larry. System wise they are identical. Most of what I've found specific for the 350 matches the Jim Weise post except some of the holes are smaller. 1/2" vs 5/8" and 5/16" vs 11/32".
 

jhodgson

New member
OK here is another question. When I built my 1968 350 there was no windage tray in the engine. Nor were there any mounting bosses to put one in. The block I am working on now has no provisions for one either. I think the one I have now is a 1975. Casting numbers as follows: Block 241748, Intake 124916-1 2bbl and EGR, Heads 1243452 appear to be non-AIR, LH Manifold 1246669-1, RH Manifold 1246656. Its a blue block with HEI. It really doesn't make a lot of difference, but does anyone know when or if windage trays were put in the SBB? I've seen pictures purported to be a SBB with a windage tray but have never seen one myself.
 
The Buick Master Parts Books show the '68-73 350 used an engine oil pan baffle part no 1380403. The shop manuals show the baffle in the cross-section views of the engine. Attached is the dealer service bulletin announcing the baffle was being deleted in early '73 along with mounting provisions.

The baffle reappears on the '79 350 and continues on till the end of production in '81. Early '79s used a baffle no 25508304 which mounted with tabs that sandwich between 2 pan gaskets along the pan rail. (These early blocks must have not had the drilled and tapped baffle holes.) Late '79-81 engines go back to using the original 1380403 baffle.

The earler 300 and 340 used a different baffle, no 1379743.
 

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jhodgson

New member
Very interesting. Thanks. It was a few years ago when I built the original 350 from my 68 Skylark. I can't remember there being a windage tray on that engine. I am pretty confident that it was the original engine. It was a cast rocker oiling thru the shaft red engine. Go figure. And if this one is in fact a 75, then the info you provided explains why it doesn't have one.
 
Nice work. And dandy machinery to work with.

The engine serial number will confirm the model year. It is stamped on the right front of the block as shown in attached drawing from the shop manual. The second character (5?) indicates last digit of the model year.
 

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jhodgson

New member
OK here are some more questions. When I got the timing chain cover cleaned up I found that it was cracked along with the oil pump end plate where the filter attaches. I have a chain cover and a couple of pump end plates left over from a V6 project from several years ago. The Timing chain cover looks almost identical to the one from the 350. Can I use it? The end plates are marked METRIC which I think applies only to the oil filter. The end plate on the leftpump covers.JPG is the broken one. The others differ with how the internal passages are cast and the relative orientation of the filter. They all accept the same gasket. Looking at the passages, would there be any advantage to using one over another? It will be used with a booster plate.
 
the Buick v6 family is a derivative of the Small Block Buick family ( the 225ci is a Buick 300ci with the front two cylinders knocked off. the 231ci is a 225ci with the same size bore as a Buick 350ci. the 3.8L and 3800 blocks are short deck variants of the 231ci ), which also includes the Land Rover v8s up until the 2004. people have been swapping the timing cover parts back and for between them for years, especially the filter mount as different applications clock the filter in different directions which can make a big difference in a tight installation.

i would carefully inspect them to verify that all inlet and outlet passages appear to function the same and be located properly and then look at port matching with a die grinder.
 
side note now that i've looked at your pdf, most of the trick guys plumb their Oil Pressure gauge to the back of the block.

since you've connected the cam galleys already, you should be able to implement the rear Oil sender by substituting a T for one of the 90* elbows.
 
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