I've been reading this forum for some time now, but this is my first time posting.
I have a l-48 77 with th350 automatic and 65,000 miles on it with the original engine in it. I'm looking at rebuilding the engine myself with the goal of a 9.0:1 comp engine that produces 350ish Hp when I'm done.
With this stock engine I would like to still be able to run 87 octane and still have the original heads on it. I've read much about these smog heads and their 76cc comp chambers and inefficient flow characteristics so 350 hp may be a little ambitious but with a better intake, good carb overhaul (cliff Ruggles) which I have already done, some mild porting by me and a decent cam (thinking the k1103 from summit) I can probably get close.
what I am wondering about is this balanced rotating assembly on ebay.

http://www.ebay.com/itm/350529800121...84.m1438.l2649

It seems to be too cheap to be true. However it has the flat top forged pistons that I was considering in any case, an entry level scat crank, connecting rods which I was considering changing, and a blancer and flexplate. So does anyone have any experience with this seller. I know that you get what you pay for usually, but I won't be demanding much of this assembly.
I could use the existing crank and connecting rods, but would still want to replace the pistons with flat top 5cc units to get the compression up and get a better cam.
This is going to be budget build so cost is a consideration but not at the sacrifice of reliability. I also want to have the option of changing the heads down the road it I want to and still use whatever bottom end is in the engine. future plans would not exceed 425 hp. Given this I think it would be best to change the crank and con rods while it's apart.
Roller cam is not an option due to cost. Flat tappet hydraulic is what is planned. Good oil with plenty of zinc will be used.
Transmission has already been upgraded and replaced with a B&M street strip th350 capable of withstanding 500HP.
I have experience re-building engines. Mostly small one cylinder dirt bikes and 4 cylinder 1200 to 1600cc motors. So this is my first experience with 8 cylinders and pushrod cam.
Advice or recomendations from anybody with experience on these 350's is appreciated.
I don't want to go the crate motor route as I like to learn by doing my own work. It may cost me more in the long run but I'll know my engine inside and out. I figure this will be my learning motor and I may build a 383 stroker later on depending on how succesful the build is on this engine.

 

I would agree that this is an "entry level" kit. I don't know that it's any kind of a "steal" though. Parts look ok. Why don't you want to reuse your crank and rods though if all you're after is a moderate performance 350. That would be less expensive and accomplish the same goals. GM cranks and rods are just fine for what you are proposing.

If you're going to buy a rotating assembly, have thought about a 383 kit instead?

 

Well I would like to keep my options open in the future if I want to just put better heads on this engine and boost the HP. Stock crank and rods would limit my options in power due to the limits of those components.
I don't find the additional $ amount cost prohibitive as long as they can provide me with what I may need down the road.
The other route I have considered is building a 383 with an entirely different block and new components. That would probably be at least two years from now though, and in the mean time I would like to have a litttle power to play with. So Yes, I have looked at the 383 rotating assemblies but right now cost is a limiting factor for me.
If in a couple years I still can't afford to get that 383 I would like to put better heads on and boost the power of the 350 without pulling the engine and making the bottom end stronger to handle it if I can do that right now with only a little more cost.
I have been reading a lot of David Vizard stuff lately and learning much about individual components and their limits. He reccomends no more that about 350 HP with stock pre 1987 engines with stock crank and rods. They can probably take a little more than that given the right prep and conditioning but again that cost more.

 

Was in the same boat as you were,needed more power!Checked my compression on the L48 all was good so I just installed aluminum heads,manifold,change cam,lifters,rocker arms,and performance carb.My block is all original and has some 85,000 miles on it.Engine has more than enough power to keep me happy.Match your components to your comp ratio and all should work out great.This is my weekend cruiser so I didn't need anything to crazy.Upgrades done so far:
Dual Exhaust of course!
Edelbrock Heads
Edelbrock RPM Air Gap
Summit 600 cfm VS carb
Crower 00320 solid cam advanced 4 deg & cool face lifters
SS Roller Rockers
Chrome Moly Pushrods
Milodon Oil pump, Shaft & Oil Pan
Crane Dist and HI6 Ignition Box
Richmond 6spd trans
No headers cuz I hate dealing with all the problems that goes with them.Had headers back in the day and hated them.
Upgrades have been done in phases to keep the wife happy and within my budget over several years.I've spent more than the vette is worth but so what,it's all mine and I enjoy it.Good Luck with your motor.[IMG][/IMG]

 

Don't dismiss the suitability of the original connecting rods. I started with a 77 L48 as the basis for my 383, and I am still using the original connecting rods. We just reconditioned the big end and replaced the rod bolts with ARP, plus balancing. That motor has about 150 runs on it now, running a best of 12.40.

 

I have been looking at a lot on kits from Skip White and have also had 3 orders from him with a grand total of about $2500. All three orders that I received had broken parts, and 2 of the three orders where missing parts that where still checked off on the packing slip.

He wouldn't answer my emails but as I bought through email I could file a case with eBay buyer protection and I then got most of the parts replaced but not all. About $30 left in parts but I just dont bother to fight any more for it.

Some of the parts received are however very nice and you really can't complain about the prices. If I lived in the states and wanted more of the external parts like intake, valvecovers etc I would maybe give him another shot but I would never buy any internal parts from that seller. If I did I would have them looked over by a professional, including rebalancing and remeasuring everything before using the parts.

I have far from just good to say about Skip White.
/ Axel

 

PC rods...he's not proud enough of 'em to put the full name.
Pro Comp
Chinese junk.
Pass.
Order your own parts and have your own shop balance the assembly. That Scat crank is fine, they make some good 3/8" capscrew rods for around $200 if you want new ones. Probe or Diamond are your cheaper pistons if you want forged, their stuff is good quality. I've seen more than one of those dampers come from together, not a pretty site. Pioneer makes good stock type dampers for about the same or less money.
Contact Mike Lewis of Lewis Racing Engines in California, PM me and I'll send you his email address. He's honest and won't try to sell you a bunch of stuff you don't need. He's sold a lot of stuff to folks on internet forums and all sing his praises. Easy guy to get along with and has been a racer and engine builder most of his life.

 

Quite honestly, never actually bought anything advertised on e-bay, and doubt I ever will. Since you'll have to get your block machined .030 over anyway, probably best dealing with a local machine shop, or a crate motor. I agree just sticking with the stock crank and rods for what you're doing. The same shop can turn the crank .010 under, recondition the rods, and balance the assembly. I'd go different heads, while at it. Now you're seeing why so many go crate, as nice just swapping things in over a weekend. 87 octane in a higher performance 9:1 carburated street engine, may be stretch too.

 

The assembly is externally balanced and a wierd mix of parts as seems usual with Skip White. Cast crank...forged pistons...no-name rods...

Aside from that, why build a 355 when you can build a 383 for virtually the same price and with the same effort?

Go with a balanced ***'y from Scat and call it good

 

Sounds like advertising hype left over from the 60's!

 

Read the full ad - it's hilarious

So much from Skip White in that ad it's hard to even think about how much of what they write they actually believe...

 

That balancer will go bad promise stay away from those

he is also recommending double checking all clearances for a reason.
I mean you should with ANY part but before assembling youll wanna go through every piece make sure it all checks out.

Get what ya pay for.

Cant give away a nice forged bottom end assy with good parts price/cheap wins every time

 

I thought "special space-aged 9000 material" was pretty funny too. But believe it or not that is how scat advertised it too. I went to their web site and checked.
As usual if it looks too good to be true then it probably is. Thanks for all the suggestions and advice. Appreciate the review on skip white axelg89 thats pretty much what I was looking for.
L88plus, I'll look into Lewis racing engines sounds like the kind of place that could help me out without bending me over.
Problem is when your new to any kind of hobby there is a steep learning curve and it's easy to get talked into something and later on you learn you've been had. Too late. Would'nt mind skipping that part of the process.

 

If you're planning to balance, be really careful about what you're buying. A bunch of mismatched parts can turn into one very, VERY expen$ive balance job very quickly...

You should be talking to your shop to find out what their preferences are before doing too much of anything else...

 

That brings up another question I have. I guess I don't have a real good grasp on the whole balanced assembly concept. There are two kinds as near as I can figure, internal and external.
Is it safe to assume that the crank itself is set up to balance out some specific combination of piston and rod combination and then as you deviate from this that some metal needs to be removed from either the crank or the rod in order to bring about "internal balance" and then you can bolt on any external blancer and flex plate and be good to go? Or is the balancer and flexplate still part of the internal balance equation?

Then does "externally balanced" refer to not removing any metal from the internal components and simply making adjustments to the balancer to bring about a balanced assembly?
And finally is a non-balanced assembly an option? I would guess to go beyond a certain rpm and/or a certain power level it would be most benificial to have the rotating assembly balanced, but is it absolutely neccesary?

 

It is easier with 6" rods and a 3.750 stroke due to the lighter pistons. If your buying a crank, rods, pistons paying for balancing, boring and it is at the machine shop anyway there is no way I would stick with a 3.48 stroke crank. Go 383 for very little price difference. If you get the right rods the material you need to remove for clearance is minor.

 

Just to make it a bit more confusing, there are actually *3* balance approaches - internal, external and internal front/external rear

...but the simple answer is that for anything other than a low budget truck engine, you'll want an internally-balanced engine. I'll give a short commentary, then someone can correct me

Exactly correct that cranks are set up for a certain amount of weight for each paired set of cylinders ("throw") - this is called the bobweight. Balancing consists of bringing each piston/ring/pin/rod/bearings ***'y to the lowest common weight within about 1/2 gram and then fine-tuning the crank to that bobweight. At that point any neutral balance harmonic balancer and flywheel/flexplate should be fine...but a good shop will want them as well. A good builder will give you the balance sheet to help with any future upgrades or replacement parts.

Where it gets ugly is when the ***'y is well out of the bobweight range for the crank and either a lot of holes need to be drilled or even worse - metal must be added to the crank. In that case, holes are drilled into the crank and "heavy" or "Mallory" metal slugs are driven in. We're into serious money at this point.

A "non balanced" assembly is one where the cylinder ***'ys are within the bobweight range of the crank and you call it good. Consider it a poor balance job.

As a very general rule of thumb, anything making more than about 1 HP/CID and/or turning more than 5500 RPM should be internally balanced.

For a guy doing something really custom, you can "do the math" and make some smart picks. If you're doing something straightforward (355/383) then save yourself the headache and buy a balance ***'y as a kit from SCAT or someone else..and count on still spending some money (~$250) for a light touch by the shop.

 

Sometimes you can get lucky with these budget Chinese kits. While I haven't put one in a Chevy, I did build a 331 Ford a few years ago with a similar kit from a place in Riverside. It came with a forged 5140 crank, Probe pistons that were 60 grams lighter than the Arias pieces that I had in there previously and they sold me a clone of a Pete Jackson quiet gear drive for $39. The rods looked identical to those in the ad; they had ARP bolts. The whole kit was $795 less the gear drive. I weighed and measured everything very carefully and I have never had any issues with it...routinely spin it to 6500+ and it makes a ton of power. One thing I had in my favor was that even though the place was an eBay vendor they were only 30 miles up the road so if there was a problem I could take it back and deal with them face to face, but after being in the car five years still no issues, and I haven't exactly babied it...

 

Yes balancing is crucial
That saves the bearings and lots more
Its money well spent and really doesnt cost much

More mismatched the parts are the more will be required.
Kits that say "balanced" have it done anyways take that one to the bank.
Nothing better than a motor that idles/runs smooth as silk.
Vibes/harmonics can do funny things to parts.

 

Besides the 'Cast from Special Space-age 9000 Material', if I was interested in this kit, I'd like to know what their balancing tolerance is. Only balancing to OEM standards is nothing special in my book.