Okay I am looking to rebuild a 350 engine. I have one in my 89 formula but would rather build one out of the car so I dont lose access to driving my car while rebuilding since the entire rebuild won't be dont all at once. What I am wanting to start with is a good 350 block. Wanting to know the difference between a 2 bolt main and a 4 bolt main, standard block and vortec block, one piece rear main seal and a 2 piece rear main seal.

I am wanting to know what a good block to get would be and a good rotating assembly to go with to start with.

I have a list of parts in this thread https://www.thirdgen.org/forums/tech...ots-links.html
on what I am possibly going with for the engine but need a good starting point and the block and rotating assembly. When completely done would like to get about 400-500 hp to the wheels but plan on putting a supercharger on it down the road to get to these numbers. Any suggestions on what type of block to start with and what rotating assembly to go with. This will be my first engine build so any help from experienced builders is greatly appreciated. Thanks for any help and info from anyone who cares to offer it.

 

A 2 bolt main has 2 bolts holding each center main caps on, a 4 bolt main has 4 bolts. There's little meaningful difference in strength between the two, don't let that affect your decision much.

There's no such thing as a "vortec block".

A 1 piece rear main seal block has... a 1 piece rear main seal. They use a different crankshaft, flywheel/flexplate, and oil pan than the 2 piece rear main seal block. Either one is fine, but 1 piece RMS blocks almost always have provisions to use a factory style roller cam setup.

The most important thing to worry about with the block is its condition. Nothing else matters if it's not in good shape, or needs a lot of expensive machining to get it in good shape.

 

Okay, so a 2 or 4 bolt main doesn't matter. Good thing to know. So what makes a vortec engine a vortec engine is the vortec heads? Okay now onto the 1-2 piece rear main seal. I am not planning on using a factory style cam, that i am aware of. Looking into a comp cam magnum hydraulic roller cam part number CCA 08-430-8 on summitracing.com Still looking for info if this is a good cam to go with. With the heads, AFR heads, I want to get they used this cam in a 350 and came up with some impressive numbers. Finally I do understand that if the block is crap it is crap. That I do know. If the block i get is used it will definitly go to a shop for some work, got a shop already lined up.

Now that I know more about the blocks any sugggestions on a good rotating assembly to go with for the engine? Thanks for the info it really helps.

 

A vortec engine has vortec heads and a vortec intake, yes.

If you use a 1 piece RMS block, you're using a factory style roller cam. The Comp 08-430-8 cam you picked is a factory style roller cam for use in a 1 piece RMS block. For a 2 piece RMS block, you'd need a retrofit roller cam, the 12-430-8. The Magnum cams are an older single pattern design, you may get better results out of a newer dual pattern cam like the Xtreme series.

Are you married to the idea of a 350, or would you be willing to build a 383 instead? If you're replacing the rotating assembly anyway, you get more displacement for the same price.

 

You cant really line up a rotating assembly until you've got a block picked out. You need to know whether you're goig to use a 1 pc or 2 pc RMS block, and then you need to know how far you need to bore it out - that will dictate what pistons you use.

So get a block machined, then you'll know where to go from there.

Just so you're aware, you can buy a brand new GM block from summit for about $700 if I recall, which is about the same as waht you'll pay for "The Works" at a machine shop in most cases, but if you can find a used block in good shape (Deck is straight, main journals are good) you'll save money that way. But then you have to worry about hidden cracks and such which are always a bit of a crapshoot with used blocks. I had a block develop a crack after 25 minutes of run time, and after all the work to put it together it had to come right back apart. You dont want to spend $500 machining a block that has a crack in it.

 

The price is closer to $2,100, plus freight, and it comes unfinished, you still need to get it machined.

Never mind, my mistake... I was searching for the wrong bore size... still $750 plus freight is more expensive than having a good used block machined.

 

Not from where I'm sitting:

http://store.summitracing.com/partde...4&autoview=sku

That's a 2 pc RMS, 4-bolt block. Brand new production line GM block $699



http://store.summitracing.com/partde...NAL%2D10105123

This is a brand new 1 pc RMS, 4-bolt block. Brand new GM block for $749


http://store.summitracing.com/partde...NAL%2D88962516

This is a brand new 1 pc RMS, 4-bolt block clearanced for a 383. Also brand new, $1149


http://store.summitracing.com/partde...NAL%2D12561723

This is a brand new assembled ZZ4 shortblock for $2300.



I dont know about them needing machining or not, you may be right on that, but there is no way a bare block costs $2100. And for me I can drive an hour to summit to pick it up, but adding freight in would be a consideration if that's not an option for him.

Edit: Whoops I guess I caught ya too quick. But maybe the links will at least help him in his decision making anyway. Those even include cam bearings... that's pretty cool, IMO. And yes, they will be more expensive than machining a good block, but they'll be about hte same as machining a block that needs a lot of help. You can easily rack up a $600-$700 bill if your block needs to be allign-honed/bored, decked, bored, cam bearings installed, and if you just want to be thorough and get each bank pressure tested there's more. You can get close to that range, and unless you pay to have the thing pressure-checked for cracks, even with magnafluxing there's no guarantee that there isnt one in there somewhere. You're always taking a degree of risk with a used block, which I've found out the hard way.

So is buying a brand new, unmolested block worth it? I definitely considered it very seriously, but I decided it wasn't. But at least he's aware that he has that option.

 

When I searched I had 400s on the brain. All that turned up were the rocket blocks.

Where I get my machining done, for $750 you could take your rusty old block, have all 8 cylinders sleeved, the decks parallel ground, and the mains align bored. Pretty much anything except for a crack could be fixed for that amount. Given the abundance of good, cheap, used blocks, buying new isn't worth it.

The old timers will also tell you about the value of a "seasoned" block, but I don't know how much of that is real anyway.

 

Machinework around here is a bit more expensive than that. I was actually told $100 per sleeve here! Needless to say I didnt bother.

 

No, I am not set on the 350 and have thought about going 383 stroker. The only thing is I am going fuel injected and do not want to go carbureted. I have been told that tuning a fuel injected 383 can be dificult so thought about sticking with beefing up a 350.

I will admit I don't know much about building engines and what parts work well with others that is why I am asking. The cam i picked is an older style, did not know that. Thanks for that. Can you reccommed a good cam. If you look at the first post there is a link to a parts list I compiled. Looking at the heads I picked what might be a good combo for them. They are AFR heads, heard good things about their heads.

As for a block and rotating assembly. how about suggestions for both styles, 1 piece and 2 piece rms. Been looking at Scat and Eagle brand assemblies
As for boring it out, most people go with boring it 30 over almost as a standard when rebuilding. Hopefully I am making some sense as to what info I am looking for if not please let me know. Just looking for info right now and thanks for everything everyone has given me so far.

http://store.summitracing.com/partde...4&autoview=sku
How about we go with this block as a starter for a rotating assembly suggestions

 

400 to the wheels on a n/a motor is a stout build. my 383 had that goal in mind. putting a blower on top that motor is not a good idea. to get 400 whp is going to require compression and thats not gonna work with a blower

may have to swap pistons later or get heads with a large combustion chamber to lower compression for boost...

pick out a good block, preferably a roller cam block. Then get a good assembly for it. 400+whp i'd do forged pistons, i beams, cast crank but get rods with larger rod bolts or good ARP hardware. Should handle that power up to 6500 rpms give or take

for boost i'd get forged everything and H beams.


as far as fuel injected goes, my 383 is HSR injected with stock wiring. my first time tuning and so far so good. I got a base tune from pcmforless and worked from that. base tune was pretty close idle/part throttle wise. MAF makes up for some things. In a good week or two my car should be on the dyno and from those numbers (if they look like what you want) feel free to copy my build and i'll send you my tune

 

Tuning a 350 and a 383 is exactly the same. The same work is involved with the same degree of difficulty.

 

As for 400-500 to the wheels, that would be with the supercharger. I might have to check around my parents farm to see if they happen to have a 350 block laying around. I know my brother has an engine, 350 i think, maybe see if he is will to part with it since it is just sitting there and he is doing nothing with it.

 

The supercharger doesn't make any difference, you still have to build an engine strong enough to handle making 650 HP or so at the flywheel, regardless of whether you do it naturally aspirated, supercharged, turbocharged, or with nitrous.

Choosing a supercharger does make a difference when you choose your compression ratio, though. If your CR is too high, you won't be able to make much boost with out detonation, and that'll limit your power. On the other hand, if you're not putting the supercharger on right away, but you build the engine to eventually have one, you'll have to put up with an low compression underperforming engine until you do.

 

Making 300 whp is much easier than making 400. That extra hundred horsepower may cost you another $500-$1500. IT's one of those thresholds.

You bore out a block as little as possible because even the maximum overbore of .060 only nets you another ten cubic inches. .030 only gets you 5. It's insignificant as far as power production goes. You bore out a block in order to make the cylinders perfectly round again as they wear into an oval shape. You only take them as far as you need to in order to preserve cylinder wall strength/thickness and room for future rebuilds. I would avoid a block that's already .030 over.

1 pc or 2 pc rotating assemblies don't matter, but you just need to pick the right part. THere's versions for both, usually the prices are the same, but sometimes 1 pc stuff costs more. But generally the prices are about the same. You pick a 1 pc or 2 pc crankshaft depending on what the block you have is.

The next consideration is what is your goal for power?

If you're in the 300 range, cast crankshafts will work fine. If you're in the 400 range, it's a crapshoot. 500hp+ and you'll probably want to go forged. A lot of people go for forged crankshafts when they really dont need to - cast crankshafts rarely fail, but at the end of the day a forged crank WILL be stronger. Forged rods, the norm is 5.7 inch rods for most of us. Then pistons.

If you're going for a power adder (nitrous, turbocharger, supercharger) then you need forged pistons. If you're naturally aspirated and money is no object, go for forged pistons. If you are short on money, some cast hypereutectic pistons are great. They're just a strong as forged, they're just more brittle which means they cant handle as much detonation, which is a big threat to motors with power adders. But they are great. Just dont get plain cast aluminum.

Depending on your power level, you'll need to get a strong bottom end. The bottom end doesn't make power, it makes your motor able to handle power.

You can use stock heads, a good cam, and a cast crank/hyper piston setup and go al ong way. Hit maybe 300-350 hp to the wheels, etc. You start going forged internals and aftermarket heads to get above that 350hp mark and you'll easily spend another $1,000-$2000 or so. Add more for a supercharger, and more than that for a turbo.

A cast crank that works great for street motors will cost you around $200. Forged cranks start around $500. Cast pistons are around $100 a set. Forged pistons are usually around $300+ a set. Forged I-beam rods that are great for streetable power levels are about $200-250 a set. Stronger H-beam rods you ened for higher powered motors start around $400-$500 a set.

Here's a really in depth post I made about putting a motor together a while back, maybe you'll find it useful?

https://www.thirdgen.org/forums/post...545-post3.html

 

Hypereutectic pistons are stronger than forged even, they're just absolutely unforgiving. A forged piston under detonation will eventually just melt, which takes a good while. A hyper-you-cracked-it piston will break into pieces almost immediately.

 

Looking at the cam selection from comp cams, since I am going fuel injected do I need the computer controlled cams? Looking at the Xtreme cams was thinking maybe the 12-268-4. Says it is good for modified 350 tpi's. How about this for a complete kit http://store.summitracing.com/partde...4&autoview=sku So far everyone has been a big help. Please keep the info coming.

 

Computer controlled cams are for compatibility with the stock ECM. If you're doing your own tuning, you'll have more flexibility in your selection.

 

Be sure to add up the cost of parts individually, sometimes you actually lose money iwth those kits.

When picking out a cam, as long as you dont go too radical you can usually get the computer to work with it, but it limits how big you can go. So if you want power and computer compatibility at the same time that pretty much means you need to go roller since you get more power for the same numbers with a roller system due to the nature of how they work.

But you dont HAVE to go roller, but at 400-500hp, it's a good idea if you want a streetable car.

 

I plan on going with a hydraulic roller cam. As for the kit that I listed, what do you think about the cam that is in the kit? Would that be a good cam to go with for the engine. Let me know what you think about it and if I am looking in the right direction for a good cam for what I am wanting to get out of the engine. Would like to build the engine to hit 400-500 but will just have to see how all the parts work together. Let me know what you think about the cam.

 

That's not a roller cam, unless I missed something. Just an xe268 on a 114 LSA. Nothing wrong with it, I'm hoping to have an xe268 in my motor if my heads can handle the lift. It's a great street cam.

But it's not a roller cam and it's not going to make anywhere near 400-500 hp. You want 400-500 hp you need to pick an aftermarket roller cam, plus a pretty stout bottom end, and you need to decide whether or not you're serious about this supercharging thing because that will affect which cam will work the best for you.

 

Not sure what I was looking at in that cam. No it is not a roller cam. Dont know why I selected that one. Here are 2 roller cams and lifters.

http://store.summitracing.com/partde...8&autoview=sku

http://store.summitracing.com/partde...8&autoview=sku

Going to get some specs on some other parts I am looking at and see what Comp Cams recommends. Looking at a set of AFR 180cc heads for the build need to get some specs on them to send to comp cams. Thanks for the heads up on the wrong cam.

 

Is this going to be a street car or a strip car? You need to decide. If it's a weekend car then you can get some pretty crazy cams, but understand that it wont be as much fun on the street.

I'd suggest probably 200cc heads for this unless you want to keep it a street car. And those cams are probably a bit on the small side, but I'll let someone with more experience say for sure what they think.

 

It is mainly going to be a street car that I can take to the strip every once in a while. Not looking to break any records with it just have lots of fun with it.

 

the only diff between 2 and 4 bolt are not the bolts.
the main webs in the 2 bolt block are way stronger. and the block will hold more power up to 1000 if you do splayed caps and a small blockfill.

 

Then here is your problem. Perhaps you've seen "cheap, good, and fast. Pick two."

If you want 400-500 hp for a street car, you're going to spend a lot of money. You can do it on a stirp car fairly easily, but it wont be fun on the street.

Horsepower is basically torque times RPM. Due to the way the reciprocating internal combustion engine works, you're going to have to figure out whether you want an engine that makes torque at low RPMs so that you can drive it around easily, or whether you want an engine that makes torque at high RPMs so you can make tons of horsepower.

You can, with forced induction or nitrous, make an engine that has a wider power curve and still get the same peak numbers, but like I said, it costs money, and lots of it. Nitrous is the cheaper option, but you've got to be careful with it.

Generally if you make 400 or 500 hp out of engines as small as smallblock chevies, you're going to have terrible street manners. It's not even going to want to work below 2000 RPM. Do you want 500 hp if it means you have to spin the motor to 5,000 RPM just to get rolling from an intersection? It probably wont be that bad, but it's a tradeoff and you've got to decide where along that continuum you want your car to be.

Not to mention at 400+ hp everything in the driveline is beyond its rated limits. You'll need a tougher transmission and the 10-bolt is just a grenade waiting to happen.


The only way to make 500 hp streetable with only 350 cubic inches is with a power adder. Do you want a 300 hp car with a 150 shot of nitrous on it? Because that's definitely doable. Or do you want a 450+/- hp car at all times? If the latter, you're going to need to start pricing out your options for superchargers.

 

Okay so a streetable 400-500 car is kind of out the question. I want to be able to drive it around town. So lets go with a 300-400 car. Thought about nitrous. Would be nice to have when I go to the strip to give that little extra edge. So lets look at building a 300-400 car instead. Superchager is still a possibility down the road.

 

It's not totally out of the question, a good roller cam and very good heads might get you close and get to a reasonable middle ground, but I'd wait for some of the other guys throw in their methods to getting there, since I worried myself more about making a street car that was fast than a fast car that was streetable when I was figuring out what i wanted to do.