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Old 06-25-2010, 02:48 AM
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327 SBC where to start?

So I have a 1968 El Camino with a 327 SB and power glide transmission. Here's what I know about the engine so thus far. The guy a bought it off of said that it has been re built but still has all the stock parts, the only thing changed was the piston heads so that it could run unleaded fuel.

So here are my questions..

I would like to beef up this engine up and don't know much about compression, or combustion ratio, gear ratio, and all of that, so it kinda leaves me in the dark with what type of Camshaft to pick.

I've been looking at the comp cam site and just got stuck. I want it sound mean and have a rough idle but don't know if i have the right compression ratio for that. Any one know what the stock compression ratio is for a 68 Elco with a 327 in it?

I'd also light to get new heads and run a Tunnel Ram (not going to lie, I just think the bug catches look awesome), but don't know what other modifications i need to make to the engine to do that..

I've very new to all of this, so any kinda help would be appropriated.

Thanks!

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Old 06-25-2010, 04:02 AM
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Quote:
Originally Posted by 68Elcamino
So I have a 1968 El Camino with a 327 SB and power glide transmission. Here's what I know about the engine so thus far. The guy a bought it off of said that it has been re built but still has all the stock parts, the only thing changed was the piston heads so that it could run unleaded fuel.
Well, you have pistons and you have heads, but you have no piston heads, unless he meant piston crowns. He may have installed pistons with a dished crown to lower the static compression ratio. He may also have used pistons with a shorter compression height, which will make it more difficult to raise static compression ratio in the motor and also will make the motor more succeptible to detonation.

Quote:
Originally Posted by 68Elcamino
I would like to beef up this engine up and don't know much about compression, or combustion ratio, gear ratio, and all of that, so it kinda leaves me in the dark with what type of Camshaft to pick.
Don't pick any camshaft. You don't know the static compression ratio. Besides, fellows who are new to this stuff always want to start at the wrong end of the vehicle. What it needs first is suspension upgrades, lower rear end gears, more wheel and more tire.

Quote:
Originally Posted by 68Elcamino
I want it sound mean and have a rough idle but don't know if i have the right compression ratio for that.
Trust me, you don't.

Quote:
Originally Posted by 68Elcamino
Any one know what the stock compression ratio is for a 68 Elco with a 327 in it?
Doesn't matter. You've already told us the former owner lowered the static compression ratio. You don't know what it is now. We don't know what it is now.

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Originally Posted by 68Elcamino
I'd also light to get new heads
OK. How much do you have to spend?

Quote:
Originally Posted by 68Elcamino
and run a Tunnel Ram (not going to lie, I just think the bug catches look awesome), but don't know what other modifications i need to make to the engine to do that..
Tell me it ain't so.....

Quote:
Originally Posted by 68Elcamino
I've very new to all of this
Yeah, you are. You need to do some reading and catch up with reality. Start here with the basics....
http://www.amazon.com/How-Rebuild-Yo...7456506&sr=1-5
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Old 06-25-2010, 04:55 AM
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Thanks for helping out, Ordered the book to find out more about SBC.

Do you have any suggestions on what type of upgrades on the suspension? what kind of gear and so forth?

Since the pistons have been changed, how would one finger out the variables that decide what type of cam shaft you choose? like compression ratio, ext.
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Old 06-25-2010, 06:56 AM
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I'd like to see a pic of yours.
Show me yours, and I'll show you a pic of mine (well, the one I HAD.. ).
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Old 06-25-2010, 07:27 AM
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The vehicle will operate best if all systems are coordinated with each other. First, are you totally hung up on the 327 or could you be convinced to build a 383 for not a whole big difference in cost? That El Camino ain't no lightweight and more cubic inches could be used to advantage.
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Old 06-25-2010, 12:50 PM
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You're 100% right, I was told that blue printing the car would be the best way to go, having all the component mapped to insure harmony under the hood. I looked online for some blue print books but couldn't find any. As far as upgrading the engine, yes, I figured that'd be a good idea, that way i could still drive the car around while i build up an engine before i drop it in, instead of having it ripped apart in my garage while I put things back together.

Any suggestions on where to find a bigger block to start that upgrade? I'm sure craigslist has something hidden in there but thats hit or miss
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Old 06-25-2010, 12:59 PM
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Hey tech,

Check this 350 block out I found on CL. Let me know what you think and if this is a good place to start!!

Thanks

http://portland.craigslist.org/clk/pts/1806111199.html
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Old 06-25-2010, 02:23 PM
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Quote:
Originally Posted by 68Elcamino
Hey tech,

Check this 350 block out I found on CL. Let me know what you think and if this is a good place to start!!

Thanks

http://portland.craigslist.org/clk/pts/1806111199.html
If I were going to start with a clean sheet of paper, I would choose a roller cam block. '96-'00 Chevy truck or van 2500 or heavier, 5700 Vortec, RPO L31. These are the last of the Gen I small block Chevy 350's, can be had in a 2-bolt or 4-bolt configuration. Not only is this the best Gen I block to start with, it has the best heads that Chevy ever used on a production 350. Look for head casting number 12558062 or 10239906. Try to find a long block, everything but the intake and buy it complete. That will give you the roller lifters, dog bones, spider, heads, valve covers, rail rocker arms, front cover, oil pan and all the little stuff that takes more work to put together if you are buying separate parts.

The block you referenced is nice, but it's not done. It still has to be decked if you are going to do it right. I see that block has been align honed. You would normally determine by how much and then coordinate a special shorter timing set for the front of the motor. Using a standard timing set on a block that has been align honed or align bored can result in a loose, sloppy timing chain. Bottom line, if the crank will spin in the oiled bearings with no more effort than spinning it with your hand, it does not need align work.
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Old 06-25-2010, 02:58 PM
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Thanks for all your help!
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Old 06-25-2010, 03:46 PM
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Took you advice, Found a 350 with everything on her for cheap.

That casting number doesn't end in 0010 so i dug further back and it looks like it could be from an early 70's El Camino.

Do these early model engine still carry some good qualities?

http://portland.craigslist.org/mlt/pts/1810934440.html

Last edited by 68Elcamino; 06-25-2010 at 04:11 PM.
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Old 06-25-2010, 09:38 PM
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That's probably a 0010 block with dirt in the casting number so you can't read it properly. Run of the mill flat tappet block. Expensive to convert to roller lifters, but ok to use with flat tappet cam if you pay attention to all the cautions and use oil additive every oil change. Easily converted to 383, depending on bore size. DO NOT BUY ANY MOTOR UNTIL YOU HAVE MEASURED THE BORE. If it's already 0.030" or 0.040" over, it may have to be bored to 0.060" over. While there are many small block Chevies out there performing admirably with a 0.060" overbore, it is not the ideal way to start a project. If it's already 0.060" and needs bored, it's pretty much junk. I know somebody will argue that they can get 0.080" pistons for a SBC, but I wouldn't persue that direction.

What I was trying to do for you is to get you started out on a roller lifter block rather than a flat tappet block. Starting off with a standard bore 4.000" roller lifter block and fitting it with +0.030" pistons, a Scat 9000 series cast steel 3.750" crank and Scat Pro Stock I-beam forged rods that have been clearanced at the bolts for the stroker crank is the bulletproof way to begin.
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