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350///357 build

38K views 156 replies 15 participants last post by  0trbo4myCHEVUICK 
#1 ·
Hello! I have started numerous threads in the past and have always been helped. Im hoping to return the favor to someone like me, in the future. (Even though you can find this build type countless times on countless sites all the frick over the place)

Going to try and post the best pictures as well as price throughout the whole thing.

First step is buying different pistons for my 1986 STOCK rebuilt short block.
Then looking for a roller cam, spider, bones, etc roller train components.

Probably going to use H345CP spreed pro pistons. Im shooting for 9:1 compression. I dont have them yet but I have 400 set back for a set of 64cc vortec heads.

I spent 425$ on the short block and 50$ on a gasket set.
 

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#127 ·
Thats too high of compression isent it? Especially with more than ideal quench distance? I'm not sure what im going to do. Not even sure how hard it would be to disassemble the short block, send it to get decked, then reassemble. Obviously if I dont know how hard it is I have never done it and im pretty nervous about it. Im pretty certain I dont want to put it together like this. Pretty sure I need lower compression as well. Who knows what ill do. Probably end up selling this damn thing and getting something else.
 
#128 ·
You'll have the same issues with "something else"
Building a motor is not just bolting on a bunch of parts and hoping for the best, not if you want to do it properly and have a quality piece at the end. I have put motors together 3 or 4 times and had them back apart, fixing stuff and making changes and I'll bet other builders will tell you the same thing.
 
#129 · (Edited)
What are you afraid of? There is not that much to it. All you have to take apart is the short block. Is your motor on an engine stand? If it is roll it over with the crank up. Look at the main bearing caps to see if they are numbered. 1-5. If not buy an engraver and start at the front and mark each cap. Take a picture when done. Now check the rods to see if they are numbered for each cylinder. To keep from getting mixed up use a marker and number each cylinder on the outside of the block. If the rods are not numbered start with #1 cylinder engrave 1 on the rod and the cap on the side facing #1 cylinder. Do the rest the same. Take a picture when your done. To start disassembly turn the crank to bring up #1 & #2 pistons. Remove the nuts. Tap on the side of the #1 cap and wiggle it until it comes off. You will need a piece of 3/4 dowel rod about 12"-15" long. You will also need some 3/8 rubber hose. Cut 2 pieces long enough to cover the rod bolts. Use a hammer and the piece of dowel rod and knock the piston from the bore. Watch the rod to make sure you do not scratch the cylinder wall. Once the piston is out bolt the cap to the rod with the bearings in them. Do the other seven the same. When your done take a picture. Now if the oil pump is on the motor remove it now. Get a gallon size baggie to keep the oil pump and bolt in. Take a picture before and after removing the oil pump. Next remove all the main bearing caps and set aside. Remove crank shaft. Take a picture before and after removal. Stand the crank on the flexplate end in the corner of your bench or someplace it will not get knocked over. Bolt the main bearing caps back to the block. Keep the bearing in place. Do not mix up. Take the crank and # 1,2 7,8 pistons and the block to the machine shop. Get it milled whatever it takes to get to get a .040 quench. IMO I would take the least amount of metal off. There are .015 gaskets that can be used. Also Cometic make gaskets starting with .027. GM has a .028 head gasket I think. Figure the compression ratio you want to have. If you mill it to .010 and use a .030 head gasket your compression will be 10.218 and 8.390. STOP BUY the PISTONS that will give you a 9.5 compression ratio. KB142 D-Cup 18cc will give you 9.525 static compression ratio. Compression ht. is 1.561. Zero deck the block and get a set of Fel-Pro .040 gaskets. Do the decision making before milling. When you get it back get a repair manual. It will have all the information to install the crankshaft and pistons back in the engine. You will need a torque wrench and some plastic gauge to install the crank. The torque specs are in the manual too. If you can't find them do a internet search.
 
#130 ·
Went to the machine shop today and talked to the guy. He got in his book and said that with the pistons .025 in the hole I would be at 9:7 compression with a 58cc head. He doesent believe me about the pistons being .038 in the hole. He wants me to bring the block up there tomorrow morning so he can measure with his dial caliper. We will see what happens but man im still nervous about tearing the thing apart. Not only because of the labor but because It would be so hard to not change parts and that gets me into more money. I was perfectly on my pre-determined 3000 budget for the entire build. Decking the block only costs 100 bucks if I can handle tearing it down and not digging too deep into my pockets for upgrades. I know my pistons suck and I would like a steel crank but probably arp bolts would be the only thing I do..
 
#131 ·
If I was in the shoes of your machinist, I might doubt those numbers, too.

The reason is the deck from the factory is supposed to be 9.025", give or take a thou or two. Rebuilder pistons are 0.020" 'shorter' in compression height (deeper in the hole) than stock production pistons.

So he's expecting to see either 0.025" in the hole- uncut deck and stock compression height pistons,

OR,

0.045" in the hole- uncut deck and rebuilder pistons (0.025" deck plus 0.020 compression height difference).

BUT! It's entirely possible to be exactly what you say it is. One way to end up at 0.038" in the hole is rebuilder pistons and the deck cut about 0.007". You can look at the deck and tell if it's been machined other than by the factory. One clue is if the suffix code is very shallow or missing altogether- if the block was decked 0.007", the suffix would definitely show it.
 
#133 ·
This motor isent far from working. The machinest and I both feel like this is going to be a solid pump gas sbc. I know upgrades would require re balancing and I don't want to deal with that. Sure I messed up thinking milling the cylinder head would help quench. It's not like the in the hole measurement caught me off guard though. I knew they were too far down when I bought it. I still feel good about this combo. Even if I end up 200 over budget for decking and arp bolts
.
 
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#135 · (Edited)
Man, I am tired of this wishy, washy back and forth. Do what you said you wanted to do. You didn't want to spend but $3000 right. Take the block to the machinist and let him check it out. You were going to get a Scat rotating assembly. It is a cast steel crank good to about 700 HP. Ask when purchasing the kit if they are using SCAT 2-ICR6000 PRO STOCK I BEAM CONNECTING RODS. They are 4340 forged steel. There are 4 different I-beam rods. The Pro Stock is the only 1 that is stroker clearanced. If you want them stronger upgrade to L19 or Arp 2000 rod bolts. Get the kit from CNC Motorsports their price is better and shipping is cheaper than Summit Racing. Call them on the phone to make sure you get the correct parts that you want.
 
#139 ·
I kind of see red when guys include the word budget and a hot rod engine build.

I coined a term.It's called a "open book build".

No budgets/no time limits.You collect the parts over as long as it takes when the funds are available.Then total when done what it cost.

Now if you budget yourself in a pile of trash parts,that isn't hot rodding.Where hot rodding is building the best.

So if you don't think your going to have the money or are not doing a "open book build"-

WELL THEN GO BOWLING.A BALL AND SHOES IS ALL YOU NEED.WALK AWAY FROM HOT RODDING AND DON'T LOOK BACK!!.
 
#140 ·
Um.....ok? Cause that kinda sounds like open check book build....some of us have mortgages, kids, wife's, and yet we still wanna play....so our junk should sit in pieces while we save to buy the best parts? Hey....wanna guess what happens next? Nothing....thats what, and the hobby looses out...because eventually we grow weary of staring at a bunch of expensive garage art that never gets completed cause real life got in the way. So how about buying what you can afford, building what your able, fixing as required, and actually getting out there and enjoying your junk as often as you can.....course what do I know, I actually used a set of.....gasp.....305 heads on my last build....ohh....and may even toss a blower on my mostly stock, completely unknown SBC I have now....but hey, tell you what, while I'm out abusing my junk, and loving every second of it, you can show us all pics of your shiny afr heads, and forged parts, and latest big dollar whiz bang speed parts all piled nicely on your bench waiting to come to life.....253am....still bored....and mildly irratated now....
 
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#149 ·
What I would like to convey to everyone is a change in thinking.Stop this nonsense about budgets. It just leads to sometime substandard work and surely has lead to substandard parts leaving alot on the table in power and increased risk factors. I kills me to read about a failure in internal engine parts where the guy loses it all and then can't afford to replace it when another $100 to $300 in parts would have prevented it.
 
#155 ·
well measured with a dial caliper and got .041-.044 on all cylinders. The machinest looked in the book and that would give me just under 9:5compression with a 59cc head. Not really sure which way I will go just yet.

The machinest says it will be fine and run it as it is.

If I knew for sure I could handle building the short block I would take it apart, get it decked for 100 bucks put it back together and be done with it. I dont want over 9:8 compression though. Im already at 9:5 with them .042.
 
#156 ·
Maybe I'm being overly simplistic when I say you have two choices......

A. Do it right.
B. Don't do it right.

Any hot rodder who knows what he's talking about will tell you that you'll be better off with a higher SCR and a tight squish than you will with a lower SCR and a wider squish.

This blurb is from Chevy High Performance magazine, but you can find the same verbage coming from any knowledgable engine builder.......

"So what are the benefits of all this squishing and quenching? The benefits are small, but often important. Pump-gas engines that run on the ragged edge of detonation, for example, can greatly benefit from a tighter piston-to-head clearance to reduce rattle. That sounds contradictory since increasing compression should lead to increased detonation. All the engine builders we spoke to mentioned that tightening the quench (reducing the piston-to-head clearance) to get it under 0.050 inch will increase the static-compression ratio, but this tighter clearance also creates a more powerful squish effect. This additional turbulence creates a more homogenous “soup” in the chamber, reducing the harmful effects of lean air/fuel ratio pockets. With all other variables being equal, this contributes to creating an engine that is less prone to detonation."
 
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