I have a chevy 350 bored 80 over. the temp runs at 190 degrees but i want to put a bigger cam in it but i need to tips on the cam becaues i dont want to go to big
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I have a chevy 350 bored 80 over. the temp runs at 190 degrees but i want to put a bigger cam in it but i need to tips on the cam becaues i dont want to go to big
Welcome to the forum.You can't bore a 350 to .080 over. Cam choices are dictated by compression ratios. We would need alot more details about your engine,trans,rear end,tire sizes,and wt of your vehicle before we could help you with a cam choice.
why cant you bore a 350 .080 over? seen it been there done that. just like you "cant" bore a 283 .125-.155 over been there done that to. works fine. taken proper precautions.
what is the compression ratio?
what heads do you have?
what gears and converter do you currently have?
Precautions??. And what would those be??.Quote:
Originally Posted by gassersrule_196
My64,
Welcome to CHR! From what I see, SBC 350's from '68 to '74 were simply the old 327CI blocks with a longer stroke, and the 327's didn't have a lot of "extra" meat in the cylinder castings for boring. In 1975 the 350 got a new block, and those built from '75 on were beefier than their predecessor's, so you might get by with a heavy bore, but why? Like Gasser says, it's a lot like the old 283's, you're pretty safe with a 0.060" bore on a post '75 block, and you might do just fine with a 0.080" bore but you might also "hit water", or thin a wall to the point that you need a sleeve to save the block. Worse, you might thin a wall just enough to be a problem, and not know it until you're chasing water in your oil, or worse. At least that's my understanding.
You'd be safer sticking with a 0.030" (355CI) or even 0.040" (357CI) bore, and chase your power needs in the heads and valve train. Share a bit more about what this is going to be dropped into, and people can jump aboard and give you a lot of good advice.
older blocks most all the time are thicker 327 had a 4.000 bore same as a 350 some engine can go to 080to 125 in bbc alot less sbc i never cut a 283 out to 4.000 bore i look at the ones i had in the shop 060 would be max the older block pre 59 may work better if you feel the need to make a 302. cutting them to a bore 4.000 had to do with the core shift at time engine was built .read the front of most makers that sell pistons books over size there on guaranty every one will bore past to or past 080 . less you have 20 core blocks and start sonic checking them you may not like what you see i done some :( most 350 and 283 like to be no more then 040. past that i going to do a sonic check
The cheaper reman's coming out of places like Autozone are those horror stories of .080. Certainly not blocks I would want to stress much. Some leaking water right out of the crate.
So being in a bad mood,I go back to what I said in the first place,the guidelines of you can't bore a 350 .080. Even if you have seen something doesn't make it right.
Now I was/am hoping the O/P made a mistake in his post. Guess we'll have to wait for him to post again.
those precaustions would be, checking for core shift, magnufluxing it among others.
have you personally built one to these specs, to be able make this assumption?
Thanks for clarifying, Pat. My info about the pre/post '75 blocks came from some "Ask a Mechanic" place from a guy who claimed to be a 30+ year chevy master mechanic, but I'd rather trust your experience ten times over. I have no doubt that Scooter successfully punched a 350 out 0.080", and from what we know (one post) My64 has one already done to that extreme, too, and his question is not about his bore, but about cam recommendations.Quote:
Originally Posted by pat mccarthy
Seems we've all (me included :o) gotten a bit off track on a new guy's question, IMO. I hope he checks back in and is not too turned off by all of the negative responses.
Yeah-this is my first rodeo...........Quote:
Originally Posted by gassersrule_196
No matter how you say it-bad advise is still bad.
well he apparently already did it!!!!!!!!!!!!!! so instead of telling the guy what a roach he has, why dont we answer his question????
Well,while we WAIT for him to reply if what he posted is really what he has,then if that is the case,I wouldn't recommend him to stress a THIN wall block like that.
As easy as it is to get a 350 block and cheap,there isn't a single reason to build a .080 block.Just isn't logical.Opps-there is my suggestion!!!.
i have a magnuflux set up dry and wet . and two other ways to check for cracks that.s not going to tell you $hit if the walls are to thin . i own a sonic checker that will tell you if the walls are to thin any thing other then that your guessingQuote:
Originally Posted by gassersrule_196
i done some 283 s and know guys have bored then to 4.000 . but very few will stand up to that . i had a 1960 i did last year and a 1959 this year . look at both for the hell of it to see if they were meaty enough for it .NO just another one of them deal were can it be done? or should it be done .feel lucky.. your talking about a block that.s been kicking around for 50+ years . 350 block or any blocks i see come in any thing past mild 70s is not thicker . one of the big piston company.s was closing down here in Mi they would sell 080 over cast piston for less then$4.00 a piston and 50. abox .they only had 080 overs when i found out. i asked my buddy that has been at the machine shop game for 40 years i asked him what block 350 he knew of would he bore that big and last ? None .funny thing about the 080 overs . one of the bigger warehouse i deal with were was trying to sell me 080 350 piston for a hell of a good deal... thats been 6 years ago .i told them were they pick them up from :) i think there still try to unload them. most of the time we check blocks with soft plugs out and used a welding rod grab the inner and outer wall you used your thumb and first finger for a mic .grab it here and there.. Hey by god i think bore it to 100 :) but there is alot you can not see .that is were the sonic check tells the rest of the storyQuote:
Originally Posted by rspears
this is why i said, "and other precautions"
[QUOTE=gassersrule_196;472208]why cant you bore a 350 .080 over? seen it been there done that. just like you "cant" bore a 283 .125-.155 over been there done that to. works fine. taken proper precautions.
There is nothing alike from a 350 to a 283.Except the 283 is much,much,older and more likely to crack. If by chance you got one 283 to run without running into water,doesn't cover ALL production 350's. They just don't compare.
Been drag racing pretty much my whole life soon to be 65 yrs old and spent yrs working in the Dyno rm at a Chevy engine plant.Not a defense.Just pure facts.Quote:
Originally Posted by gassersrule_196
It is interesting here that you never said anything at all about the most important precaution needed. Sonic check for wall thickness. Even at that "if" you get it bored out that big,it will leave the bore's wall so weaken,it is just a short matter of time before a issue occurs. Then to shorten that time up,to tell this O/P to install a performance cam is bad advise which given what the forum is about,I couldn't just let it go. Again,just the facts.Quote:
Originally Posted by gassersrule_196
In my opinion,you can not,should not,generalize advise based off what is a well know proven high risk factor. I'm just doing my part here with just the facts.
Going with such a bore, would this mean using a small diameter cam & clearaicing ( notch )the bottom of the cylinder like in stroker motors?
Looks to me like the OP gave up with everyone bad-mouthing his .080 block and not answering his cam question that he gave up and left.......
BTW, Scooter has been around here awhile and posts all his draggin' plans and results.... He had a couple smokin' sbc's in that little yellow Nova and for me if he sez he had a + .080" block, that's enough for me to take it as fact.... Like I said he's a real racer and doesn't just post "what if" scenarios and things he read online somewhere.... I think most of us realize that sonic testing a block is a common procedure prior to going to a large overbore, hardly anything worth quibbling about anyway....
I'll stick with real racers and people who actually build engines for my information any day!!!! You Da Man, Scooter, keep twistin' them small blcoks!!!!!! (Even if the "experts" tell you it won't work) ;);):D:D:D
awwww--scooter's going to be driving rigs where the wrist pins weigh more than his crankshaft did in the sbc
But,but,but,I did answer his question three times telling him I suggest for him not to put a performance cam in a .080 block.:LOL::LOL:
There is a hell of a difference between a screaming gasser of yrs ago and a certain expectation of "windowing" a block to throw it away vs a guy who is just purely out on a cruise night finding his engine puke all over the hot dog stand's driveway.
Don't think the experts ever said it couldn't be done,it just not advisable and like with the gassers of old,won't last.:rolleyes:
David.In terms of me personally.I did my time in C/MP and D/PM with moon shot SBC's. I built them,drove them,and blew them up. Rockcrusher 4 speeds,welded spiders,and all. So been there done that.:);)
you can bore a 350 80 over caues ive did it and drive it everyday. i got it from a guy and its just sat in the back yard for some years untill this year i went through it and built it the year of the motor is from 77-79 bored 80 over caues its stamped on the pistons with some older 327 heads
First off,I want to say I am glad you cam back. Do think we have talked about both sides of the topic. Debates like is aren't common,so I don't want you to get the wrong impression. I do think I clearly stated my opinion and therefor moving forward I'm out.
My64,Quote:
Originally Posted by my64
Thanks for hanging with us through all of the off-topic rambling that never addressed your question. You can choose to believe what you want from whoever you want, but you've got the engine, you use it regularly, and it's been doing fine for you so bore size should be a moot point from this point forward. Can you share some details about what it's in (for weight reference), what gears you're running, stick or auto, and maybe tire height as well as what you're wanting from the new cam? With that we've got a few guys who can help guide you in your cam selection.
its in a chevy c10 stepside, its a turbo 350 auto. its got the factory rear end and gears in it and weight im not to shure
and since it is bored 80 over i was just wondering on the cam and if i could go biger becaues if i do that it changes everything and i figuerd alot more people have did an 80 over on a 350
The C10 gives an idea on the weight, as opposed to a 2500# street rod. Are you just wanting more "grunt" for playing, and using it as a daily driver or are you wanting torque for towing? About what rpm do you turn at say 70mph on the highway?
lol yes wont last been going strong since 1999 lol i have no idea what im doing**)
original poster, your original gear may be 3:73's thats my guess pretty common stock gear, what compression do you have, what intake and carb do you have?
so he raced a 080 350 :) no a 283 more luck then any thing if not sonic checked .but small engine with no stroke not much wall loading is there . no dave the expert use a sonic checker then they tell you IF it will work . seen any 4.080 bore race pistons ? last time i checked i do machined many REAL race engines this year :) need a listed of names and numbers . but tell me i did not ? i am getting old .my mine may be playing tricks on me???? . the deal here is just bullshit as not one of you guys would take a good 350 that would clean up and go to 080. and if some one posted on here ... if smart ...would say the next over size to clean it up and save the block for another rebuild . or what would you pay for any engine thats been bored to the hilt on bore size? .am i missing something ?the guy pick up a engine and wanted to know about the cam hitting as the bore was bigger ? and said it was 080 thats alot and he knew that ? but did not know if the new cam would clear or what cam would? that is no .the rods will not hit the cam. use any cam that will fit for piston to valve clearance work for your build.
and just to get things out there you can take a 350 and bore more than 80 over you can go all the way to 120 over. this 80 over build is not my first but i have never put a bigger cam in a motor with that kind of bore
if you know all stock gm 350 can go 120 bullshit .. very few are sound at 060. very few make a race piston that go past 060 . i have a machine shop with a rotter f2b thats bored alot of iron blocks . i sleeved the f#$king things and started to break threw shade past 100.. you can hear the walls go thin just by the sound of the bar cutting . if one makes it lets see what happens when you put a deck plate on it with out a short or full fill with block rock.yes you can bored a dart SHP block out to 4.165 . i bored many bbc from 4.250 to4 4.500 then to 4.625. them are not stock blocks. if you know how far you can bore them you should know any cam will fit if you have the PVQuote:
Originally Posted by my64
yes your a good machinist but not the only one around. my stuff is built and built right. it does not break. yes sonic checking is a good idea i never said i just pick some random piece of shite and go for it. i see the bickering has not stopped on this site.
and yes i have build .125 and .155 over 283's and .080-.100 over 350's. big whooptie do.
if 8500 rpm and 13:5-1 compression dont test things to its limits tell me what does?
Attaboy Scooter, come out with all guns blazin'.....:LOL:Quote:
Originally Posted by gassersrule_196
Oh man.I thought I was done here. Please tell me the minimum wall thickness that you yourself have machined??. On the skirt side and on the wrist pin side??.Quote:
Originally Posted by gassersrule_196
What are we doing here anyways??. This is the engine section of the site. I started the ball rolling by saying you can't bore a 350 .080. THAT IS BASED ON COMMONLY WELL KNOWN PRACTICES!!!!. I'll be dammed if it isn't good advise. The engine section should be technical based. Based on in this case,machinists like Pat and Jerry. Not some defensive personal vendetta trying to prove yourself. And not some off the end of the dock haft cocked popularity contest.
Really it is quite simple. The performance industry came up with aftermarket blocks solely because over the yrs time and again it proved a need because of the limits of bores the production blocks. It along with other improvements in design has a market for those aftermarket blocks because of a "majority of people" agree with those limitations.
Now you can go on and on about your adventures,thing is it is risky.That is the facts. Facts that the mass majority agree with. Facts that created the market for aftermarket blocks. Facts that well beyond this site prove your advise is also risky. Facts that the industry of engine building also agree with. You imply this should be a commonly done practice.The history of boring engines does not support that fact.
Don't think your the ONLY one with the history of drag race.That would be assuming a ton. As I said already,in my past I owned,built,drove,two /MP cars. But I am getting side tracked to my point. In drag racing as you know there is a saying. "It is much better to be lucky than good". Given your suggestions...............seems to me you have been pretty damm lucky. Humm,NEVER had a failure???. I mean really??. NEVER??. Almost sounds impossible.................
Modified Production, huh???? You've been out of drag racing for a long time if that's what you ran, Gary!!!!!
Going with what the majority of people say will work and not work will get you performance just like the majority of people.....Average, at best...
People who actually accomplish something most of the time do things differently then the majority of people do, that's what makes their performance better and their combinations so unique.
Anyway, my point is, what are you running now??? As I mentioned before, Scooter puts up his combinations and where and when he was racing and what the results were, not just fairy tales of what he did or is going to do, or what someone else did!!!!
The things one did decades ago don't mean do-do, what are you doing TODAY?????? What are you building, what are you running, what have you built that is still in competition TODAY????
Most all of us post our current projects, plans, and build data, then back it up with pictures in the photo gallery.......
The old adage that a picture is worth a thousand words holds so very true in this case as well as most cases.... Obscure and vague references to something that may or may not have occurred mean very little.......
Here's a good plan to end all the bs and name calling, Scooter is planning and saving for his next car, how's about you do the same and we'll give the whole process say, one year......then the two of you can meet and go heads up!!!!! You gonna just talk the talk or are you going to walk the walk???????
I've given him plenty of opportunities to prove his knowledge.Twice about the most critical of all tests, sonic testing and now what I am asking him about wall thickness.
Me,walk the walk??. I have said it before.A Top dragster where partnership agreements limit posting pictures. If you expect me to post what we have found for a edge,that isn't going to happen. Thought given his ref,I thought talking about moon shot SBC's the time span was the same. Ya know with him living back in the day.............:LOL::LOL:
But this is silly. Commonly accepted practices do not recommend .080 bores let alone anything bigger. .060 is the standard. That is something we all know.
HMMMM boy you got me :) big deal there grass hopper . i push limits on more then one engine get back to me when you built more then a hand full of engines or more then 50? then do them for a living and over head on machines and get a MIK so state will let you hall wast out ? your way of thinking may change on playing with so..so parts you know could or may work... mine has ...when you get paid to do it.8500 RPMs with 500of NSO is nothing .i have engines that do that is that the bench mark? . just think how well a engine would run if the walls were not moving seening on how you would not say how you check the 283 i would bet it was not sonic check if so lucky . you shoud look at what i said? to what i posted go look back show me were i said NO engine could be bore over 100. you know some guy may read this post and think all 283 can go to 4.000 now a 50 year old block jacket rust = thin walls. and all 350 can go to 100. with out checking them NO . as for me as a machinist i let my customers speak about my work 1999 is not a big deal i paid four BBC 454 back in 85 to find one that would go that far and one had walls that could be bored and walls would not move that engine s is still at the track . .have a great day :)Quote:
Originally Posted by gassersrule_196
Quote:
Originally Posted by 1gary
Yer funny!!!! Why would one possibly limit picture posting of a race car??????? I'll bet you get a lot of sponsors that way, huh??????:rolleyes::rolleyes::LOL::LOL::LOL::LOL::LOL::LOL:
Yeah.The partner hates forums like this. Really can't understand why??.:rolleyes::rolleyes: Says he got nothing to prove. He owns haft and has the right to ask whatever he wants.:) Might be the reason why we have been together so long.:HMMM:
Sponsors don't come from media like this Dave.
But enough about me.Right??. Cause like my partner. I sure don't have either anything to prove.
The standard for boring a 350 is still never the less .030 or.060. After that common recommended practices of .060, is not to go beyond that point. It is known factor by all of us.
I am saying this as a off topic issue.It certainly is a common problem that all forums suffer from. Debates don't have a foundation based on the facts,but rather on attacks of the creditability of a poster. I am saying this for the benefit of this forum who has a wealth of talent in many,many,areas. If only we would come to a meeting of the minds based off the facts even when we disagree.
In this case. No need for me to post pictures of my racing operation and break a long standing agreement. I have consistently posted the facts. Sure wish you guys would stick to that. Last time(I hope),commonly accepted boring practices for a 350 SBC is not to bore one .080. To drive this point home is one all of you guys know.
Anybody that bores an engine ------rule of thumb is you'll get 6 cubic inches for .030 overbore
Anybody that is boring .030 or .060 looking for performance won't get much from the extra cubes, but it is an opertunity to refresh an engine if that amount of overbore won't violate the rules. The piston manufacturers of stock type pistons typicaly only make a few sizes--.020 sometimes, usually .030, some .040s and .060s--the generic rebuilders out there just jump to .030 as the first over bore as that will generally clean up a moderately used/abused cylinder wall.
If you are looking for CUBES, I and most anybody else doing PERFORMANCE type work will suggest strokers these days and/or replacement aftermarket blocks such as Dart because they can be bored out enough that you do get some inches-------
We will, on a rebuild of something special---do a clean up hone with torque plates to see how much it takes to clean, and then order pistons for that size---it is also not uncommon on a rebuild to have a couple of cylinders a different size .
Scooter has been deep into this from a pretty early age and has seen results pro/con of results that others talk about but haven't turned wrenches on.
It is a little known fact that he had a very special experimental cam of well over .800 lift that was made special by Bruce and Dave Crower years ago for a 287 sbc----------he has worked in teck at a race track, and for a well known car collector-----