Hey hambers I am wanting to build 350 for my 54 belair what years are the best to build,what years have a 4 bolt main?I dont know if it realy matters I just want to run decent and last awhile. CAN YA HELP ME OUT? KILLER.
A 2 bolt block actually has thicker main webbing. If you have your mind set on a 4 bolt main block, find a 2 bolt block and order up a set of splayed caps. This will require align-boring the mains, though. The end product is much stronger than a factory 4 bolt block. If you're building a healthy street engine, there's nothing wrong with 2 bolt mains. Bottom line, don't believe the crap they try and shovel in HOTROD. Talk to a professional engine builder and get the facts.
your best bet is pull a motor from a Chevy or GMC truck in the 1970's, almost all of them had 4-bolt mains, they're actually quite plentiful
I am curious if anyone has ever experienced failure due to main caps? I have never seen it personally. I am sure there is some instances, though. I have heard, that the 4 bolt mains were designed for standards that did a lot of down shifting in work trucks etc. Any truth to this?
Not on a chevy But I blew the crank into the pan on a ford 302. Ripped the main bolts right out of the block, most of the threads were still on the bolts. It didn't like 10 grand very much.
I'll add to the 76 truck block, that's what I have. Do a search online, there are lists showing the casting #'s for the blocks. The numbers are located on the back of the block right side behind the head. I would say get the best condition motor close to you that you can spend, regardless of 4 bolt or 2 bolt. How much HP you planning? 4 bolt can be overkill if your not pushing massive hp. I know of 305's running 400hp with a 2 bolt main.
I belive the block all the roundy round guys up here want, is the 010 blocks. Hi nickle or some crap like that.
FWIW, I remember reading a tech article where some big engine builder tested the two bolt block to see how much power it would take to cause main cap flex. The HP level was near 600 before any main cap movement was detected.
If you want a 4 bolt the best place to look is in a 3/4 or 1 ton truck. early to mid 70's are the best one to look in. most all of the 1 ton trucks had them (read Rootdawg's post...yes there is truth to that) Casting numbers don't mean anything when looking for a 2 or 4 bolt (the most popular casting number are "010" or "020" which will be the last 3 numbers of the casting number and be on the front of the block behind the timing chain....these are popular becase as said before it indicates thier "nickle content") Tips on finding a 4-bolt main. If you know the motor has never been touched.....look for a 8" harmonic balancer, also above the water pump on the block itself there maybe a small oil plug. If the motor has both of these there is a good chance that it is a 4-bolt main. but i did see a late model '90 block out of a 1 ton truck with the 8" balancer and the oil plug and it was only a 2-bolt, so your best bet is to look for an older truck. The ONLY way to be sure that it is a 4-bolt is to pull that pan. That being said: What are your hosepower goals for the motor??? 2-bolt small blocks are good to about 500hp: edit (or as the post above indicates 600hp testing) and your not going to achieve 500hp on a small block without throwing some serious $$$$$$$$$ into it - regardless of the "HotRod" articles you read on how to built a budget motor. As was said before your better off using a 2-bolt block and buying splayed caps for it.....but if you are building a motor that NEEDS splayed 4-bolt caps then you might as well go with an aftermarket block. personally I sell all the 4-bolt blocks that i get or find and make money cause everybody has to have one "its got a 350 4-bolt" oh yeh??....who cares. I've never seen a 2-bolt chevy lose a main cap. but I have seen a 302 Ford block break in half....literally (on a 200hp shot and 8k ) I'm not trying to steer you away from doing what you want to do..but ask the question... Do I really need it? (i.e. is your car going to have lots of traction and be hauling a 10k# load of whatever? or is it going to be a tire smoker ?) What are my REALISTIC power goals for this motor? good years to look for are '69-'79 cause they have a little more meat to them. i would also recommend going to your local Border's or Barne's & Noble and buying a book on building SBC's - brose through them and get the one that you can understand best and is the easiest to read. there are lots of good ones out there
I'll add to what people have already been telling you... I personally run 4 bolts in my stuff, because I drag race a lot, and I tend to beat the hell out of my motors, BUT: For anything under about 500hp or 6000 rpm, I would have no reservations at all about using a 2 bolt block. As a matter of fact, I have a 11.6:1 406 with splayed caps that I spun a main in (of course, the idiots that built the short block had a lot to do with that! ), and as soon as I can afford to , I'm taking the guts out of that block and putting them in a stock 400 2 bolt block! With round cylinders, this motor should be over 600 REAL hp, and in it's previous form I was shifting it at 7300! But, if you decide you NEED a 4 bolt block, I've got a big ol' pile of 'em I'll sell ya! Steve
Arkracing has made some very good points...... But I would like to add.......Get a 1987 up 350 Chevrolet 350. The block will stand 350 to 400 horsepower easy.....and have NO oil leaks....the 87 up blocks have a 1 piece rear main seal and a 1 piece oil pan seal. I have had 5 or 6 with over 150 thousand miles and be oil leak free. Unless you are a experienced engine builder......and I figure you are not by the question you asked... ..Lots of the time, you are better off just buying a new 350 from Chevrolet. All new stuff.....with a warranty. The ZZ4 is 355 hp, has aluminum heads and intake, a HEI distributor.....runs great, has the new style no leak valve covers and oil pan and is ready to rock....with 4 bolt mains....for less than 4 grand......you add your carb and fuel pump and spark plug wires. Just like the photo below.... By the time you buy a 4 bolt main block......and all the new parts, do machine work and then PAY someone to put it together.....you will be real close or OVER 4 grand .......with no warranty. Disclaimer........I do not work for GM ....I am a retired sign maker.....
My next to last SBC in the HellCamino was a two bolt block. I never dyno'd it... but I'm guessing 400-425 hp. It ran 12.70s @ 105 at a weight of 3600# It also survived a couple of dozen nitrous passes at anywhere between 11.00-11.50 (120-125 mph) depending on traction or which guardrail I was facing. The two bolt blocks are fine. Use good bolts for the mains and rods and you will be fine.
For all your Chevy casting number needs. www.mortec.com 2 bolt main blocks are fine.Think about all those early 'Vettes that had 327s in 'em & got the $hit revved out of them. And yes,as mentioned above,the pan needs to come down to be certain.
Quite so. Every 265,283, and 327 produced used two bolt main caps, and I beat the hell out of several of those with no ill effects. Come to think of it, how many Olds/Cadillac/Chrysler hemis ran with two bolt mains after being bored to the limit, with a blower, on nitromethane? I'm sure that a two bolt block will haul your rod up and down the street sufficiently.
as they said, there's no need for a 4 bolt, but if you insist, get an 010 block (last 3 digits of the casting number) from a 70s pickup or suburban. Almost all of the 1/2 tons had 4 bolt mains, except for the trucks that came with 2 bbl carbs. Although it's getting hard to find a truck that old that still has the original motor in it. I rebuilt a 4 bolt 350 in a work truck once that had one of the main cap bolts lying in the pan when I took it apart. wierd.
looks like a late production 010, notice the newer style (square) serial number pad. Apparently the 4 bolts petered out near the end of 010 production in the late 70s.
My two bolt 350 has taken alot with no problems. When the block was at my machinist, I had ARP main studs installed as I've been told they're easier on the main webs and prevent main cap walking if it REALLY gets beat on. Anyway, its doing great and as all the others above have said, plenty of racing Chevys had two bolts long before there were four. The '49-'64 Olds rockets were two bolts and favorites for blown gasser engines as were the two bolt Mopar hemis of the '50's. I wouldn't worry. Best advice given me was to find a virgin motor that hadn't been overbored before. LUCK WITH YOUR RIDE!
Even among the 3970010 blocks, there are good, better, and best. Sorting them out requires removal of the timing cover. Some blocks have no numbers cast there, some have an "010", and the best have both "010" and "020" cast there. As it was explained to me, the numbers indicate the percentage of nickel and tin in the cast iron used in the block. The 010-020 blocks are 20 per cent nickel and 10 per cent tin.
oh, that urban legend again.... I did some research on this, and came to the conclusion that the numbers on the front of the block indicate which block casting numbers the front mold was used on. for example, this block has 014 and 010 in the front area, and 014 and 010 were common block castings (this is a 3970014 block, it's the one that was usually used to make a 2 bolt main 350 in the early 70s)
I'm guessing I have about $1500 in the engine. Stock smogger heads,w/ss valve,screw in studs & plates 2-bolt 350 block .030 over Stock rods & pistons Stock crank .010 under Erson single idler gear drive Childs & Albert roller rockers 268 Comp flat tappet hyd cam Stock HEI ign Edelbrock carb & manifold And alot of MY labor. Thanks for the compliment,& it gets with the program pretty good in the lightweight car.
Geez if you're in trouble then mine's really really in trouble - got the same basic setup - a 406, all forged, internals, 6" rods, lightweight pistons, internally balanced, ported 220cc runner heads, 14:1 compression, full roller valvetrain, spayed billet mains, and I've had it to 8200 - typically try and keep it geared around 72-7400 - FWIW this is in a circle track engine and they'll dyno 520-540Hp at the wheels. For an on-topic reply, my 355, 12:1, stock rodded, 2-bolt main went 4 seasons of racing at 6500-6700 and now needs a refresh just for insurance... 2 bolt main's can hold up just fine - it's all in the prep and assembly. For a street engine I wouldn't get hung up - I'd just get whatever block was cheap and build from there.
are you saying then that there is no truth that the ".010" or the ".010/.020" blocks are any different than a regular casting and if you guys are buying ".010" blocks by using the casting number you are gonna be dissapointed some of the time Fred
This is a very educational thread. It puts emphasis on that old addage that "saying something don't necessarily make it so". I know a guy that swears 4-bolt main sbc are stronger. I'm going to copy this for him, so he can take a rest on the subject. Not knowing this personally, I'm still going with the post that explains the strength of the web is more important than the number of bolts. As I understand it, aren't the bolts in the 2-bolt larger than the in the four?
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