Well then Bob, maybe a slight nudge is in order. :Brow: From the 350 head gasket it appears they will bolt up to the 350 block but the unknown is the camshaft. If we find a solution to that issue all that is left is headers and intake. Headers should be available for the 300 and 340, and I understand the stock manifolds with a balance pipe are quite good so that leaves the intake. Let's face it, if the 350 guys start snatching up these heads, somebody is going to start producing an intake for them, even if it's Sean for instance, but before that happens all it would take to use the existing intakes are a pair of spacer blocks, and a set to adapt a 215 intake would be thick enough to have injector bosses. Considering any halfway decent mig welder can weld aluminum sheet or plate, a fabricated intake is just not that big of a deal anymore. So I think we need to be finding the right cam bearings to allow us to use the early cam in the 350 block. Very likely they exist already and can be found by a careful search of a bearing maker's catalog. But we have to know what sizes to look for. So... anybody got a 350 cam laying around? Jim
I've ordered a 340 head gasket just to verify. It will be in tomorrow. Laying the 350 gasket on the 340 block and 300 aluminum head, the only thing that does not match up are the 2 steam (or coolant) holes at the top along the lifter valley of the 340 (and presumably 350) block. The iron 300/340 heads do have these holes but the aluminum heads do not, nor do the 215 heads or blocks. In fact the 215 does not have the bosses for these holes, so while a 300 aluminum head will work on a 215 block, a 215 head would only work on a 300/340/350 block if these holes are plugged. Same with a 300/340/350 iron head on a 215 block. So I'll sort of go out on a limb here and claim that the Buick engineers didn't consider holes in these location to be desireable, even though they put the bosses for them in place when they designed the 300. Apparently the aluminum heads are fine without them. All the bolt holes, end coolant passages, locating pin holes, and oil passage holes for the rockers are correct. The 340 gasket may not have the section that contains the pushrod holes judging from the catalog picture, we will see. I doubt that makes any difference. So back to the cam. Someone want to measure the journals please? Just to clarify, ALL of the holes do line up properly, but the '64 300 heads do not have the top two coolant holes. Jim
I will measure my 350 cam and post tonight (Aust. time). I think that the deck openings are to give better support to accurately locate the water jacket cores during the casting process with the bigger 3.75" and 3.8" bore iron blocks and thin wall section. On sbc race engines they tap and plug all the core openings in the deck and install studs to prevent the decks from cracking and to push all the coolant to the rear transfer passage.
1970 350 camshaft. All journals are 1.787" (45.4mm) diameter. The centre journal is 0.787" (20mm) wide, as cast. Measuring from the side of the centre journal to the side of the lobes with inside vernier against the "as cast" surface. To the rear, cyls. 5&6. 0.290" 1.063" 1.854" 2.610" To the front, cyls. 3&4 0.196" 0.984" 1.811" 2.578" Also measuring from the flange thrust face to the front (side) of the lobes, centre out. 5&6 10.22" 10.99" 11.785" 12.56" 3&4 8.433" 7.7" 6.89" 6.122"
Thanks Wal, I wrote those down, put them in my pocket and will do a closer comparison. The rough numbers look real good, differences could be variations in the manufacturers, I doubt the tolerances on spacing and lobe width are that close. I measured from the thrust face back to the center of the last lobe in each group: 4-1/4 8-1/4 12-7/8 17-1/8 One group of your numbers didn't match up as well as I would have expected, check those dimensions if you wouldn't mind. All 350 cam bearing journals are the same size as the front journal on the 340. How convenient. So we add a .015" thick ring under the 2nd shell, then .030", .045" and .060" to take up the space and use early shells and cam. Or we find thicker shells with the right bore and OD. 1.7875 is 1-63/80, kind of an oddball fraction even for an engineer. In Metric 1.787 is 45.4 mm so I thought maybe the size is based on the bore plus shell but that comes up complete gibberish. Closest thing I've found to a common dimension is the bore of the rear journal which is about 1.8 but it still has the shell and freeze plug in it so is hard to measure. Not that any of that particularly matters, I could turn a set of sleeves on my bench lathe out of 2" hollobar easily enough. If I can do it I know TA can do it. So I think we have to say the cam journals won't hinder us overly much. We're probably OK on the lobe spacing too. Let us know how close those numbers are to your cam. Here's the 340 head gasket compared to the 350. Nothing there that I can see causing a problem. If you look real close you'll notice two things. The 340 gasket does not have the steam holes, and the 340 gasket has the combustion chamber flared out just a little at the valves. The 350 gasket would work fine but it'd be closer to the edge of the chamber than the 340 one. The area of the opening would be about the same in either case. That leaves the intake. Jim
So we add a .015" thick ring under the 2nd shell, then .030", .045" and .060" to take up the space and use early shells and cam. there's an idea. i would suggest looking for bearings that could be stacked inside of each other but by the time you got out to the small end of the Rover style cam it would be getting pretty stupid.
If what you guys are finding is correct, I have not doubt you are, wouldn't it be easy to get a Poston or TA to make a special cam for the 350 block. It seems the later design of single size would be more robust. Wouldn't the idea of stacking bearings lead to a spun bearing fairly easily?o No:
The 350 cam journal size 1.787" or 45.4mm is (approx.) width + 1 inch. (lobe spacing and journal width) All the measurements were taken twice or three times. In my previous post about the misaligned lobes I said cyls. 6&7 but should have said cyls. 5&6. The best thing to do is to get a 300 or 340 cam, wrap some masking tape around the end journal so that it is close to 1.787", put it into a 350 block and give it the eyeball test. I will do this the moment I can get my hands on a 300/340 cam, however in this part of the world it is not so easy to get get your hands on such things for these purposes. You guys in the States would have a better chance of getting this done. As for the cam bearings, either find some that will fit (unlikely), make some, or get hold of a raw casting and machine it to 350 size.
350 cam thrust face to centre of last lobe in each group. 4.33" 110mm 8.7" 221mm 12.8" 325mm 17.14" 435.5mm P76 cam 4.33" 110mm 8.58" 218mm 12.91" 328mm 17.125" 435mm
I haven't re-checked that yet but I found out why the measurements we're seeing are different. I put a 350 head gasket on a 300 head and looked at how the pushrod holes line up. (The 350 gasket has pushrod holes) The outside ones line up fine but there's a big difference in the two center holes, probably 3/8" or so. It's very clear what's going on here as the two center intake ports sit between those two pushrods and by splaying the 4 center positions they were able to get an extra 3/8" or so each for port width. (Or maybe the 350 is the one that had the geometry splayed, I don't know.) Obviously to have proper valvetrain geometry with that configuration the lifter bores should be moved, and if you do that the cam lobes should move too. This makes it perfectly obvious why the cams would not be interchangeable, assuming the lobes actually were moved in this way. Why the P76 is so similar to the 350 I can't say. So that means to use a 340 head on a 350 you probably need to order a custom grind with a 340 layout ground on a 350 blank. I really don't see where this should be that much of a problem. Custom grinds aren't that much extra and you get the chance to tailor the cam to your car. But it does bump up the cost a little. It would probably be cheaper than making sleeves for the cam bearings though and you have no extra parts that way. I still think someone should call a cam maker and ask if they use different lobe locations for those two cams though. In my book that would be the best way to resolve the question. However, since it doesn't look like I'll be building a 350/300 someone else will have to do it. Jim
I put a 350 head gasket on a 300 head and looked at how the pushrod holes line up. (The 350 gasket has pushrod holes) The outside ones line up fine but there's a big difference in the two center holes, probably 3/8" or so. It's very clear what's going on here as the two center intake ports sit between those two pushrods and by splaying the 4 center positions they were able to get an extra 3/8" or so each for port width. this is excellent information. thanks for your work Jim. that's an application of the block design differences that i hadn't considered. :spank: IYO, would this make a "dual application" head unfeasible?
Not at all Bob. It means a custom cam of course, and those 4 pushrods will be angled a bit funny but it isn't extreme. It also may mean the solid pushrods have to be used for their smaller diameter, and two of the pushrod holes in the heads might have to have a oblong shape That may be enough to make it work. But much depends on how big (wide) the ports are made too, at some point you just run out of room. Jim
Crane Cams list the 300/340 together with part numbers begining with 890. Buick 215 and Rover V8 are listed with part numbers begining with 900. The P76 should be in this group. P76 pushrod holes are about as close to the port as you can get. As the hole extends upwards it takes a gouge out of the port wall. I will try to have a look to see if the P76 head clears the pushrods. If it does, the 300 head should too, but it may need some grinding on the bottom corners of the port wall. I don't think it will be a problem and a custom made cam will make the bearings work.
I finally got all the parts together to check the pushrod clearance. I checked the passenger side (U.S) centre intakes. With the 350 cam a sbc lifter and P76 pushrod, P76 head with its tandem pivot bracket mounted rockers and a checking spring, everything fits and looks okay. There is no interference but there is no effective clearance between the pushrod and the side of the port. Solid pushrods of smaller diameter would solve the problem as far as I can tell. The angle of the pushrod is hardly noticeable (at a glance) and the rocker shaft mount will accept whatever side thrust is generated. I don't know if they will need uprating or not. It would be better to do this check with a pushrod of the exact correct length as the P76 one is a bit too short.
http://www.v8buick.com/showthread.php?t=172229&page=4 here's the link to the thread page with all of the pics of the foundry goodies.
The good news is that Mike Jr. thinks they might look into this. Since they will have the castings soon for the Rover style heads it shouldn't be too hard for them to find a 350 block to test fit them on, I'd even guess someone close by might help out there. But my guess is that it's still going to take a custom cam blank and an intake to make it work. On the up side, an intake that will work for the 350 with the Rover heads should also work for the 340, plus IR intakes will also work. But the cam blank could be a sticking point. Still, it could be a win for you 350 guys, and it could also be an easy route to yet another engine choice for the British V8 crowd. This might be a good candidate for one of those roller cams. Jim
it shouldn't be too hard for them to find a 350 block to test fit them on, I'd even guess someone close by might help out there ermmmm. as much engine building as they do, i'ma go out on a limb and guess they have one sitting around? :bla:
