What info do you need? I have a 373 in the works Also gsjohnny will know as his 363 build took just about the same work as a stroker
what clearances do you have at .100 offset. and what is the max offset that can be done with the 1.850 crankpin. how close is it to cam. I have a combo in numbers that puts me at a 366 with a .040 overbore. nascar rods found a set of forged pistons that will give me 8.3 comp if my setup gives me .070 in hole.
Hopefully Bob can give further info to answer your questions however here is some info: There are a few variables with the amount of clearance. Factors such as camshaft profile can create interference between the crank throws and the camshaft its self and that is even without being offset ground to stroke the engine this is with factory spec crank, rods, and an aftermarket roller camshaft. The shape of the con rods where the big end bolts are can be an issue. All in all it is great to stroke the 350 a bit if you can just keep in mind that there is very little cubes to be gained with stroking. I would be willing to bet money that the largest CID Buick 350 so far was a 90 overbore and no stroke added vs the 369 inch which was with a 30 overbore and 14 cubes of stroke added. I am not saying that all blocks can handle a 90 thou overbore but my point is that there can be a lot of money spent to stroke the engine and it is not going to be a game changer compared to getting better head porting instead. To be honest I think that Bobb just wanted to pick some stuff out and make it work together, had it been 360 or even 355 cubes I do not think he would have minded all and the HP and torque would have been very close to what they ended up with. It is different if you can go from 350-383 cubes with adding stoke but do not get too worried about giving up 10 CID. A 355 at 30 over has room for a few re-bores, no issues with interference or custom parts required.
I typed out a lengthy response bit of it didn't go through.. Cliffnotes. Not sure on max offset with 1.85 bearings as I dont think anyone built a 350 with them yet But you may be able to squeeze a 4in stroke with a .105 offset.. Take any of gsjohnnys overbored engines either his 363(.075) or 366(.090) and you'll yeild an extra 10 cubes. He didn't have clearance issues with rod bolts..if you find my hershy rods vs lentz you'll see why. I'm 90% sure you have to modify the rod tangs. And def have to balance engine externally. My 373 will use chevy 283 spec pistons .nascar rods set for 1.888 bearings I got off ebay and .100 offset grind crank..should be 9.2:1 comp ratio. ---------- Post added at 08:41 PM ---------- Previous post was at 08:30 PM ---------- Oh and the 369/370 is .100 offset stroke w/ .060 ob and 1.888 bearings..not sure the exact offself pistons bob used. But believe they were oldsmobile? Unless im mixong thst up with the 300 stroker build ---------- Post added at 09:24 PM ---------- Previous post was at 08:41 PM ---------- If you stick with a flat tappet cam you shouldn't have cam interference...yes, going with a roller cam you can most certainly hit the counterweights on some...not all cranks.. ---------- Post added at 09:38 PM ---------- Previous post was at 09:24 PM ---------- If you stick with a flat tappet cam you shouldn't have cam interference...yes, going with a roller cam you can most certainly hit the counterweights on some...not all cranks..
a 4.00 in stroke would be good. 8.51 comp with 040 overbore is a 371 .that would be .115 offset.Just talked to PER engines out here,they would do a stroker but they don't do cranks inhouse that would be sent out for grinding.
Any progress on this? Would love to see someone use a 1.85 rod bearing with a 4 inch stroke (.105 offset)
I think its .150 and if we could that much or alittle more wiseco has a supercharger piston from ford 3.8 that is about .200 less compression height so it would work out well depending on rod
You can go .150" more plus whatever undersize bearings are available for that journal size. But be aware,if you go the max undersize,if something happens to the crank you'll have to start over with another crank. (if .060" undersize are available then .210" extra stroke would be possible,but then the jounal size would be 1.790" and decreasing journal overlap even more) Heat treating the crank would be good insurance to help save the journals by making them more wear resistant(and possibly making the crank a little stronger?) if something like a cam being wiped out happened and sent metal throughout the engine. At this level build,consider a small base circle roller cam to avoid a cam wipeout situation? You will definitly want the rods with the smaller big end diameter that uses the 1.850" bearings,I know of 2 different rods that use this size,one has a big end diameter of 2.008" and the other has the 1.976" big end diameter. The smaller big end rods will give you a little bit more cam clearance(you'll need all you can get),but most of them use smaller wrist pin diameters. Either custom pistons will be needed,or some sort of fabricated reducer sleeves will need to be made to use off the shelf pistons. No one said this would be easy,but it is doable.GL Derek
My rods are H beam 6.350 big end 2.008 with .827 pins .I believe there is enough material to drill out for .927 pin. What's the best year blocks for a .060 overbore
Rumor has it that the 68-70 blocks have more meat but I have no proof of that. Any 350 should be safe to bore 60 thou. I would not even bother sonic testing as long as the core shift does not look too bad. Remove the frost plugs on the sides of the engine and compare thickness of the block to see an idea of core shift. I prefer 30 thou bore and then it is safe for another rebuild or two... Starting at 60 thou limits your options down the road. If going max effort NA build then I understand looking to max the cubes but with power adders it is not critical to gain the cubes... Just add another PSI of boost instead of spending $1000+ to add 10 cubes.... Like said above one of the drawbacks to maxing out the specs and doing a custom spec stroker 350 is that many times the crank will not be able to be re-cut during a rebuild down the road. Another reason I stay with 30 thou overbore and stock stroke.
I always heard the 70 sp code block was beefier..but rumors are just that.. Logically if any 350 blocks were to be better then others, it'll be the later years ..but again it's all just theory or rumors as for bearing and crank..atleast for 1.88 ACL is where its at http://www.aclperformance.com.au/ or these guys.. http://www.obbco.com/custom-babbitt-bearings.html?gclid=CPC4p8SQjKwCFccbQgodI2wZmA My stand on performance N/a engine is you cant beat an engine that beathes..which means .50 ob or more for forced induction, yes bore size isnt much of an issue, neither is STroke(but more is beneficial for turbos atleast)..just run desired boost to compensate. ..but, everything comes out better with the most stroke and even ob as possible. 3.80x3.85 < 3.875x3.85 3.80x3.85 < 3.80x3.95 3.875x3.85 < 3.875x3.95
Hopefully a mild build done right will last along time if anything a low compression stroked 350 with 450 HP n/and 425 ft lbs would make a nice convertible engine. Talked to Jim wiese. awhile back and he nitrates? BBB cranks .guess it helps strength . I am stuck on a stroker build at this time. If it implodes I always have my 455
it wont lol You're less likely to spin a bearing with the smaller 1.88/1.85 bearings then you are with the stock buick bearings
You'll want a minimum of .110" wall thickness left on the pin end of the rod after altering(thickness without the bushing),.100" would be .050" less wall thickness per side,plus the thickness of the new bushing,which can be as much as another .030" per side. The later 455 blocks are said to be "beefier" than the ealier ones(the "blue blocks"),this may also be true with the 350 blocks as mentioned before on this site that the deck heights are taller on the later ones,so maybe the rest is thicker also?Perhaps it has something to do with the casting process,after time the molds,or patterns get bigger,or smaller?(not sure what the block making process is,so I can't say for sure.Investigating the block casting process may lead to an answer to how aging tooling effects thickness?) Andy,do you know what bearing undersizes are available for your rods?(I really like your idea of the undersize bearings for even more stroke!) A max bore max stroke sbb350 would be very cool!:TU: With a .090" overbore and a 4.050" stroke would yield a sbb 387 CID,a little more than the 10 cid that Sean was saying.o No: Without boost with good flowing heads in the 260 cfm range with a boost friendly compression ratio of around 8.5:1,you should be able to make around 440-490 hp with close to 500 ft lbs of torque plus or minus(460-500 +) depending on the cam.:Brow: (I'm just guessing on the numbers based on what Anthony got with his sbb 370) N/A with 10:1,with this cid and the same as above flow should be capable of close to,or more than 500 HP with the same toque in a higher rpm range,depending on cam choice. With more extensive port work even more potential from a N/A engine would be possible.,maybe even close to 600 hp with those kind of cubes?(and still pump gas street friendly):eek2: I wish you the best of luck if you move forward with this project,and I hope you are sucessful if you do build a max max sbb stroker.GL Derek
A taller deck seems to work out for a stoker in my thoughts as you can run longer rods as I'm not a fan of zero deck .like a little more valve clearance. My rods are set for 1.888 bearings. Would like to see .150 stroke but even.110 is OK just need to know what clearance limits come in. I am going this way with my build and collecting the needed parts. Then will see what happens
The rods you have,they make both 1.850" bearings and 1.888" bearings for,I have a set of nascar dyno takeouts that have the 2.008" housing bore with 1.850" bearing that came with them. So you can go either way,which ever ones you want to use,dealers choice.:TU: Derek To be on the safe side if your doing a boosted app. anyway,a small base circle cam might be a good idea to help clear the cam. A boosted app. cam wouldn't be all that radical anyway,so cam deflection shouldn't be of much of a concern.
