This happens every time someone asks about what to do with the 350. Why do you think I was griping about changing to a stroked engine. most people do not even know how to put a cam in it let alone putting in Nascar rods with the special changes needed to the crank. Then everyone attacks me for saying it. Now the OP is gone. I am even getting pm's from a person that I do not know his name and he now calls me delusional....but at least I am funny ha ha.
I'm guessing that there's something factual about the new engine package using the Nascar take-out rods to inspire enough confidence to extend a bearing replacement schedule from yearly to more than 3? Not a bad improvement for such a potentially cost effective upgrade. I'll call that point proven. I'm always impressed seeing how far factory parts can go. Even though Derek and I don't see eye to eye on some subjects, I can relate to this one. It's always better to see what the limitations are when someone else's budget and reputation are at risk. I definitely do things with my own I wouldn't even consider with engines built for others. I also avoid proving the life of suspicious parts whenever possible. Parts are cheap. If the Buick 350 were offered as a performance crate engine from someone reputable and had the choice of a factory rod or an aftermarket one for close to the same $$, would anyone choose the factory rod engine? Neither side would take that risk. Since everyone already knows that the stock SBC rods are often tough enough to get you into the 10's, why did "they" ever make aftermarket ones? That's all I was getting at.
Moyock is here! Just reading thru these threads and sipping my morning coffee. If anything else, you guys are good for Saturday morning entertainment! I don't always get the chance to check the forum so I'm out of pocket sometimes. I want to say that I appreciate all of the responses and information. We could go a little easier, we all have the same goal! Go fast as you can, as inexpensive as you can! How everyone arrives at their own destination is the really interesting part. I've got a SBC 350 on the spit being built for a 63 Nova. Then I've got to rebuild a 53 Chrysler 331 Hemi that I stumbled across. The SBB is interesting to me simply because I've never built one before and the more I read the more it may get pushed to the front of the build list. Haven't a clue what it'll be used in. Like I said earlier, I'd like to find a 66 GS or something close. But who knows. Not much of a NO2 guy, I'm more old school and would like to get what I can out of the SBB with just carbs. Anyone ever run a tunnel ram on a SBB? Just curious. Please keep on responding, you guys are a hoot! :3gears:
I'm not against the stroker idea. Just would like to see some results. We already have more stroke than bore an NO modern engine is built that way. Adding more stroke just for the sake of cubes is not the way to go in my opinion. When/ if some of these are built and there is test data to see that opinion may change. Also getting machine work done properly is getting more difficult everyday.
Nice! Lots of engineering there. Got a wild hair this afternoon and started to tear the SBB down tow see what I have, So far I've discovered a cracked flex plate and the front aluminum housing is cracked. But I read somewhere, probably here on V8Buick, that it was common. So I'll keep pulling it down for inspection and cleaning, Then comes the decision, what to do. I'm a recipe kind of guy, I find a decent build and follow the bread crumbs. The whole discussion about stroking is interesting. But I'm a little confused, I always thought you'd need to buy a stroker crank or like stroking a SBC grind a 400 crank. But the decision seemed to say to grind the stock crank? Help me out here fella's. And the over bore on a SBB...? Yikes! Is that true? You could punch a SBB up to a 4" bore? Okay, lets talks heads for a bit. Are worked stock heads worth the effort or would it be just as easy to pick up an after market set? When is too big for valves?
I see no reason not to increase stroke, unless the idea is extreme rpm with a really light vehicle. Hasn't the addition of stroke been proven by now with pretty much every engine family out there? Are we going back to a flat earth? :laugh::laugh: Just kidding. I hate to use generalizations, but assuming the hp potential is the same between the 2 versions with the stroked engine reaching the intake tract's choke point at a lower rpm, then how is it not a benefit to enjoy more response and torque throughout the entire powerband? Assuming the same top end. On top of the strong mileage increases I see from adding stroke and cubes there's also the fact that larger cams/ports/valves, etc. are calmed down some in their behavior, the reduction of swirl or other mixture motion from porting is made up for with higher piston speeds, etc. ... If the argument is more friction then big deal, one should be taking advantage of the thinner and lower tension rings we have nowadays. Mountain motors spin what rpms with a 4.750" stroke (or whatever)?? The SBB is blessed with a tall deck, room in the crankcase, a very stiff block and a top end with potential to handle more cubes in a streetable rpm range. The weight to cubes ratio of our musclecars begs for more cubes and stroke.
Back in the ancient days before stroker cranks could be purchased the stroker cranks were made from stock cranks by setting the crank grinding machine to a longer stroke, thereby grinding more material from one side of the rod journal, increasing it's throw. Each journal was done in between hand forging horse shoes of course, and to let the machine cool down or for the river to be able to recover it's level in order to turn the big wheel that powers the belt driven plant. :grin::grin::grin::grin:
The way that you can stroke the Buick 350 is to use rods with a smaller big end vs stock so the crank can be offset ground to add stroke. There is not too much room to add stroke but it is possible just not very well documented so it's tough to say how much you can add before the rods hit the camshaft. For bore it is normally accepted that 30 over is what most of us do for an overbore, and if needed some people go 60 thou over. I personally bore only as much as I need to and no more. Sonic test if you want to go over 30 over or skip the sonic testing and go 30 or less. I have heard that some engines may handle up to a 4" bore but never seen or heard of any success stories with this. Then you can get custom head gaskets for $250 that will allow large Overbores. I agree with the others that are good with sticking around 350 cubes, why mess with a good thing? For heads there is currently no aftermarket head options but Ta performance is currently making a head and it should be out in 3-4 months. I called and made a deposit so I can get one of the first sets. Valve size is limited to not too much larger than stock.
Dam Steve, you live like 10 minutes from Enginecraft!! Dave can do just about any kind of engine machining you can dream of, if he can't do it he knows guys that can. Machining from Dave on engines that I have built have went to 8,500 RPM without failure!(I told him not do rev it that high anymore and to set his rev limiter to 7,500 because that is where the rods are rated for.) Dave's engine balancing skills are as good as it gets and he's only abound 10 miles from you, so you should be the last effing guy to complain about getting quality machining done. And as for "NO modern engine is built that way." You need to take a look at a Ford 5.3L, that effening thing has a 10.037" deck height with a 3.552" bore with a 4.165" stroke for crying out LOUD!!! WAY WAY WORSE the sbb 350 ever thought about being!! I know, I know Fords don't count, but hey that's how they make them. Or is that modular engine not "modern" enough? That forced induction Lightning F-150 is pretty dam fast for a factory 4,000 plus lb vehicle if you ask me, the small bore long stroke just seems to LOVE boost!!! Derek
As the stroke is increased for use with an eBay nascar take out rods the rod journal is decreased as well as the bolt to bolt dimension of the nascar eBay rods. When increasing the stroke by having the crank offset ground .140" the rod journals get a new centerline that is .070" further away from the main journals(half of the total because when the crank turns from the top to the bottom it will travel .070" further up and .070" further down from the mains centerline for a grand total of .140" more stroke. With the extra stroke and a rod close to the factory's length will make it kick out further away from the cam in between TDC and BDC. Also the bolt to bolt distance on the nascar rods is lesser than the factory rods by around .150" depending on which rods are sourced. So .150"/2= .075", that is .005" per side more clearance than the increased .140" stroke compared to the factory rods are with the stock stroke. The engine built by Finishline Performance didn't mention one bit of cam clearance issues when going with a 3.990" stroke with the 1.850" rod journal size from the build I posted the link for that got them to 370 cid with a .040" overbore and using a custom Scott Brown cam. Derek
Thanks Derek I tried once before to explain that an offset ground stock crank using narrow big end rods actually can increase the rod to cam clearance while also increasing stroke. You did a much better job! Different Subject: Max 350 overbore. It is a good practice to keep at lease .100" cylinder wall thickness between adjacent walls for performance use and of course much more on minor and major thrust sides. If you are willing to except this as a good guideline you can do a quick check before sonic testing just to give you an idea what the max bore limit is for that particular block. If you take a block without freeze plugs and measure the gap between the cylinder walls in the water jacket area, add the gap distance to the lowest acceptable wall thickness for both cylinder walls which will be .200" and subtract that from the cylinder bore spacing 4.24", that will give you the largest bore without violating the guideline. That's assuming no core shift. Basically if the gap is more than .040" a 4.00" bore will have marginal wall integrity. Paul
Well....I told ya didn't I? lol. man this thread got really technical. There is so much Buick knowledge on this site...... Gotta love it!
No problem Paul, I'm here to help get the info out there. I have explained this several times here in various threads, once using the sbc 400 and how the General used shorter rods(5.565") for it rather than the common 5.700" rod length with every one of the other factory sbc engines ever made as an example that I thought even explained it better. o No: For the sentence in bold, what would be the minimum wall thickness for a block filled about a 1/2" from the top of the bottom side of the deck? Or all the way to the bottom side of the deck? Thanks in advance Paul. Derek
Would like to meet with Dave some time. Next time you go out there on a Sat or Sun let me know, I'll buy lunch.
Okay fellas, finally found the engine serial number, WC 050. So, I'm guessing that this 350 was somewhere between 1971 and 1972, maybe when Buick was transition from one year to the next. Pulled the heads, the intake valves look to be about 1.8 ". I'm not seeing much room for improvement with larger valves. I can post a picture if you all are interested. How would I tell if this motor has an after market cam? It looks to new, not much wear, to be a stock or original cam. Moyock
WC code was at least originally a 8.5:1 compression 2 barrel engine. The front of the cam should have some stamping to ID it. Yes there is not too much room for larger valves but we can use 1.92 intake and 1.55 exhaust. Head porting is the biggest power gain, if done properly. Matching the compression with the camshaft, is very important.
Interesting, is it possible that the heads could have been swapped out at some point? The casting number says 71 4 barrel, and it has a OEM 4 barrel manifold. Might I say "heavy" 4 barrel manifold! Anyone know of a good, Buick centric, machine shop in Northeast North Carolina?
