Sorry Paul,it was late(very early),and I didn't do the math,so yes,usually that would be enough material on the high side to clean up the journals when indexing. But if your crank shop would check(they have to be told to do this,or they will just start cutting to get the stroke you tell them to stroke it to,and just go to the next udersize to where it will clean up) to see what stroke the crank can be stroked to,that would be more ideal before any cutting is done. Well worth any extra charge so undersize bearings won't be nessasary.(Paul,I'm sure you know all of this,just want to get that info out there for anyone considering doing a stroker with a factory crank):Smarty:
I would personally like to thank you two fo this info These types of conversations are what is needed to take engines that are often out of the spotlight and put them into the forefront Also i wonder if ,with a 3.85" stroke crank,if it really is necessary to worry too much about adding stroke,when one would think getting it up to the magical 4in bore size would be much more important for making serious power,and getting all the much needed air out of an already induction limited engine Good stuff guys
Nick The .100" stroker is a freebee due to available aftermarket rods that will fit the 350 SBB. Please bear with me while I give the whole story One of the problems with building a 350 SBB is aftermarket parts availability and/or cost so one solution is to look at using inexpensive Chevy aftermarket. The problem with the 350 SBB is the tall deck which requires longer rods than the early generation SBCs. Second problem is the SBB rod journal is 2.000" and the majority of the SBCs are 2.100". The breakthrough comes from the Chevy LS series which has longer aftermarket rods. The Eagle LS rods come in 1.899" and 2.100" journal size and the Callies Compstar LS rods come in 2.000" and 2.100" journal size So that leaves the Eagle 6.460" and 6.560" rods with 1.899" journals and Compstar 6.340" and 6.440" rods with 2.000" journals. The 1.889" rod allows you to offset grind anywhere from a .100" under stroke to a .100" over stroke which gives you a .100" range in piston compression heights to work with when looking for an off the shelf piston. The smaller journal also reduces the bearing surface velocity. To finally answer your question, if you are doing the 4.00" inch bore engine then you will be using a custom piston anyway so it doesn't make sense not to pick up the extra .100" stroke. The head and intake manifold restrictions can be dealt with later. A side note: The Callies Compstar rods are a big step up from the Eagle. What blew me away is Flatlanders is showing the Compstar rods @ $549. More to come this week Paul
To add to this conversation here is my 2 cents: If I had to pick either adding a larger bore or adding more stroke I would pick the larger bore just due to the fact that I feel it would help the cylinder heads flow better than the added stroke would. That being said if we have to grind the crank for a smaller journal to use the economical rods then we might as well add a bit of stroke while we are at it. As a side note I have heard that SOME 350 blocks have been good to bore 90 thou and lived a long life with that large of a bore at least for racing. Also the 68 and 69 block castings are said to have more meat than the later castings.
Thanks Sean That's the kind of info we need. I was wondering how long it was going to take to get you in this conversation. We need your expertise. The goal here is to dig as deep as possible and compile all available combinations of parts and services in one place. Paul
You are welcome, between all the people on here we can do some great things with these underdog engines! The first time I heard about the large bore helping the heads to flow better was from Sonny Seal who ran 11.08 in the quarter without power adders and at full Skylark weight. He talked about how the heads he was selling me were flowed with a 3.89" bore diameter and how using a 3.83" bore would huirt the flow numbers. I was not concerned as I am using boost however for NA this is a big help. I also heard about the large gain from a 60 thou bore from the NHRA guys later on. The only thing to be carefull with on the large bores is: 1. Cooling capacity. For a street car this is important and a large overbore is not the best idea in most cases. 2. Sonic testing and core shift. Some blocks are thicker than others and the core shift is a common issue that limits large bores on many blocks. Like Sonny said it took him a bunch of blocks to find one thick enough. Some other noteworthy info is that raising the roof of the intake port is a great way to increase the head flow. If using a custom intake manifold this can be exagerated and the new intake can take advantage of this. When using a stock, TA, or Poston intake this can still be done but not to the same effect. Here is a picture from Gregg Gessler's site showing a Buick 350 heads like I am talking about for a custom intake: http://www.gesslerheadporting.com/g...ebd9bf8032792df785256dec0059ab55!OpenDocument I am pretty sure the above heads went to Ed Sullivan who was also running 11s NA with a custom stroker 350 that was about 380 cubes. I have more info about this build in my book but I do not have it here at work tonight. the basics are: 380 cube, 13:1 compression, no power adders, custom hogan dual 4 barrel intake manifold, the gessler ported heads, custom crank work to stroke it, custom rods, custom pistons, run on alky. I agree, and the place where all the best info will end up will be in my book which will hopefully help people gain easy access to the information without having to look through a million threads on the computer.
>> I looked at "Hectors" work. It's commendable to see such dedication, for the cause. Would it be possible to vertically split a mopar single plane manifold, straight down the middle "non-heated' ? It appears the 350 sbb has more deck height than the sbm. ? The new verticle split halves would separate, to bolt directly onto the sbb heads,(bolt pattern change) ? The gap between the halves, would need a welded-in or machined/o-ringed spacer. This would further require a carb spacer/adapter, because manifold plenum and carb bolt patter, got wider. There are verticle split manifolds, on the market. They are much easier to port and flow match. Good Luck, roverman.:idea2:
Stroker: I had an issue with cam lobe clearance with the stock stroke when using Scat rods in my 340 and had to cut the shoulders and chamfer the bolt ends. I went for .050" clearance to the lobes. IIRC. I have trouble imagining that any other aftermarket rods would be that much different in that more or less critical area, since you have to have enough beef to hold the threads of a capscrew type rod and will almost always want the oversized bolt. No doubt the Hersche and other application specific rods will clear, but I have seen nobody address this very critical clearance. Seems like when stroking by offset grinding it would not really be any less of a concern, at the very least something you would want to check. Intake: That idea has come up before but I'm not sure anyone has tried it. You could be the first. I'd lean towards welding just because it'd be more reliable in the long run. Again, shimming the heads up would give you more metal to remove from the port flanges to true them up. Jim
As far as I know the mopar 340 intake has to be cut into 4 pieces to make it work, obviously this is not an easy option. Yes the stroker issue is tricky due to clearance being tight with these engines, this is one reason I never went that route. The other reason is that with using boost I have not need to chase every cubic inch.
Jim Good point! Were the Scat rods that you used an "H" beam design? The Eagle rods are a 1.899 rod journal size and if they are dimensionally smaller on the outside of the big end there would be less of a clearance issue. Paul
If you "really" want to flange sleeve a 350, and not spend a small fortune,(MID sleeves),that leaves the Ford F-600 flanged sleeve, new about $30. ea., on ebay. 3.905" bore means, "maybe" LS3 shelf pistons.CP Pistons cuts the valve reliefs at 13 deg. vs 10deg., for sbb. Point is you "might" not need to re-cut. I would use a 1/2 block filler, or more, since its now a wet sleeve. This makes more sense than banging the cam, with the rods. Good Luck. roverman.:TU:
Lets look into this "sleeve" idea further! I am just waiting for an e-mail woth the detailed info about Bob mackleys stroker Buick 350 (380 cube). I am featuring this engine in my book, as it made 420 HP NA at 8:1 and 630 HP with a few PSI. Now with the boost cranked up to about 10 which is stil conservative it is about 800 HP and relaible being a street car.
Hey Jim,thats a SWEET car you built,anyway,when stroking a sbb factory crank the NASCAR take outs from ebay are good canidates to use. Most of them come with carr 3/8" bolts and the bolt to bolt distance is narrower than a stock rod. I measured the center to center distance from rod bolt to rod bolt,here's what I came up with on a few examples; Stock 350 sbb 1977 cap screw rods are roughly, 2 5/8"CTC,and are 3.200" wide. Nascar Carrillo 6.200" H-beam cap screw rods with the 2.015" housing bore are,2 9/16" CTC and are 3.150" wide. Nascar Carrillo 6.200" H-beam cap screw rods with the 1.976" housing bore are, 2 7/16" CTC and are 3.100" wide. So if the 2.015" diameter housing bore rods won't clear the cam with the 1.850" bearings,the 1.976" diameter housing bore rods with the different part number 1.850" bearings should with .025" per side more clearance?(not sure yet,but will soon find out,I have both sizes) Both of the Carrillo rods are radiused in the cam interference area,and probably can be angle cut if more clearance is needed. :Brow: If the Scat rods you used were the small journal sbc rods with bolts and nuts(didn't think they made them that long),then I can see why you had issue with them. The sbb 350 rods bolts have the angle cut on them from the factory(I think,not sure,but the ARP bolts from TA are),and probably are shorter than the chevy bolts also,as pictured on the TA website.(probably why the pre 73' rods failed when the power was cranked up.)o No: I hope this helped.:TU:
Here are four LS Chevy rods long enough for the SBB that can be found for under $600. Eagle CRS6460H3D2000, 6.460 length, 1.889 rod journal<o></o> Eagle CRS6560H3D2000, 6.560 length, 1.889 rod journal<o></o> Callies Compstar CSC6340CS2A2AH, 6.340 length, 2.000 rod journal Callies Compstar CSC6440CS2A2AH, 6.440 length, 2.000 rod journal Automotive Machine & Performance carry dish and flat top Diamond? forged pistons in limited quantities for around $750 a set. 1.875 CH, .840 pin<o></o> Mike said for a little extra he can have the same pistons made with the Chevy .927 pin and adjusted pin CH to fit the Chevy rods. <o></o> Paul
Ross Racing Pistons has already designed and made a high comrpession piston for the Buick 350 that has a SBC pin diameter and valve reliefs. This is a flat top piston that yields 11.5:1 with a 6.300" long eagle SBC rod. Job card # 115793 They also told me they can change the compression height for any length rod we want to use, or if you want to build a stroker you can take that into account and use the compression height of the piston to get the compression where you want it. Also like Paul says the Diamond pistons are very nice and they told me they can make them any compression height or whatever pin we want. In fact I have a spare set of Diamond pistons for a Buick 350 and they have the following specs: WRIST PINS = SBC DIAMETER BORE= 3.845 COMP. HEIGHT= 1.335 DISH = 6 cc ***If anyone can find a rod that works with this piston then I can sell them for less than they cost new.***
Paul,don't forget these rods that are made for a flat head ford can be altered to work in a sbb. They are 7.00" long,with a 2.125 housing bore for 2.00" rod journal,and a .750" pin, big end width would need to be narrowed also. http://www.ebay.com/itm/Eagle-H-Bea...Parts_Accessories&hash=item3f22520357&vxp=mtr And this is a less expensive option(different brand); http://www.ebay.com/itm/New-Flathea...Parts_Accessories&hash=item2ec6238d0b&vxp=mtr A piston with a CH of around 1.250" would work,the mathimatical number is 1.263". (so custom pistons would probably be needed) The ad says they will handle 700 HP,should be enough for most builds.:Brow: These rods would give a 1.82:1 rod to stroke ratio,for whoever likes a bigger rod to stroke ratio.(a standard 350 ratio is,around 1.658:1):TU:
What would the compression be using these diamond pistons? Asume a 40 thou gasket and a 58 CC head: WRIST PINS = SBC DIAMETER BORE= 3.845 COMP. HEIGHT= 1.335 DISH = 6 cc
What rods are you going to use with these pistons,and what is the deck clearance? The flat head rods are .072" to long,unless you could find a block that is taller than spec.,and maybe use thicker head gaskets also. Spacers for the pin isn't that big of a deal either to go from .927 to .750,that would give the spacer a .0885 wall thickness,and could be made out of bronze or aluminum.(dealers choice) I've read on here that the later blocks have a taller deck than the older ones,but can't remember how much. So say you can find a block that has .050" more than spec.(after clean up),you could use a .060" gasket to get .038" quench distance.
The reason the pistons are still on the shelf is due to me never finding rods to work with them. Ford flathead rods might work. I happen to have a 60 thou thick head gasket and a block that cleaned up and ended up 45 thou over stock spec deck height.... That given what would the compression work out to with a 45 thou overbore and a 58 CC head.
Assuming the head gasket hole diameter is 3.900",then the compression would work out to be roughly 11.43:1.
