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  #31 (permalink)  
Old 06-14-2012, 04:36 PM
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man!
for your compression ratio calculations just use this site, it's extremely accurate:
http://www.csgnetwork.com/compcalc.html

the 8cc (in the caluclator it would be -8cc) pistons and factory combustion chambers (64cc) you would be sitting at 8.9:1, I would want more than this. you want to be in the 9.2-9.5:1 range. you will likely (or i suggest) atleast milling the heads .010-.015" just to level the surface out. this will help a lot in getting your head gaskets to seal properly. i very seriously doubt that you are going to get away with keeping it a standard bore, you mention that the you think that the block had already been decked because you say that the pistons are flush with the top of the block at TDC. this is something that you will need to buy a set of feeler gauges ($10.00 at a parts store) and a metal straight ruler to acutally check. if it has been decked there i would be almost certain that it has been bored already as well. so it may already be .030 over bore. you may get lucky and only need to go another .010" (total of .040") over to clean the cylinder walls back up.

the cam you listed would work but you will definatly have to have the guides ground down and have springs capable of handling that lift installed. those factory springs will only take about .440-.450" lift before they start to bind.

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  #32 (permalink)  
Old 06-14-2012, 05:12 PM
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Thanks for the calculator, it matches what I got: 9.5

NOTE: my heads should be 58cc not 64cc, that's why we have different numbers

I'm not sure if the block has been decked or not, and I am without pistons currently. If I clean the block good, put down the metal ruler, and use feeler gauges, how much variance is acceptable before it needs to be machined?

As for if it's bored or not, I need an inside micrometer to check, right? (thank you David Vizard) Based on the bore, I can just change to pistons to match. (A 0.040 overbore with corresponding gasket change and a 9.5cc piston puts me back at 9.52:1) I can do a similar process of adjustment depending on how much the shop takes off the heads.

The valve spring change I understand. However, a quick google doesn't reveal anything about grinding down cam guides. Any info on this for me?
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  #33 (permalink)  
Old 06-14-2012, 05:14 PM
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Quote:
here is some good info to follow, how to build a 305 http://www.gregsengine.com/pictures/305chevy/index.htm
Thanks 1BAD80! That will be invaluable once the actual process starts!
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  #34 (permalink)  
Old 06-14-2012, 08:06 PM
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If you need block / head mill work that is going to be 375+ , are you sure about that 305? Guilty of parts creeping now. It is the truth. Once you start the machine shop it is something to think about.

In a 305 the performer cam with performer intake is nice. Under 175 and get a ring gear for the rear. A budget stall around 2400 you will like too.

My 305 shortblock was semi-fresh so i kept it. I got 906 vortecs for $179 pair with beehive v6 gm springs and rockers. The whole vortec head roller 350 was $450 and it did not need any machine work , except a quick self driveway hone. These are everywhere, and you can even get them cheaper.

Headwork, paid some spainish speaking guy $80 at napa to mill my heads .040" after hours. then put some new umbrella seals on it.

When i find that 400 smallblock my 305 is gone faster than you can say...
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Old 06-14-2012, 09:10 PM
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Well, the shop said it'll be $25/head. IF the block needs decking, $125 for that, but I'm not sure if it does or not

The cylinders look good, no obvious scars, but I'll wait until I use the micrometer to say for sure. I can do the honing myself, but I'll use them if I need to bore it.

Best case: $50 for refreshing the heads
Worst case: $250 ish to bore/deck the block and refresh the heads
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  #36 (permalink)  
Old 06-15-2012, 10:31 AM
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50 for the pair that is low, what is included? 250 for tanking, bore, and deck is low as well. Starting block prep is around 390, and they do not even put the freeze plugs in.

If you can get someone to mill the pair .030+ and match the heads to the intake for less than $80 , you are winning.
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  #37 (permalink)  
Old 06-15-2012, 10:45 AM
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Well, they don't do hot tanking. Apparently, they "can't use the good stuff anymore 'cause of the EPA." I'm cleaning everything up myself. The plan is a good ol' fashioned self-serve car wash!

The 25 bucks is just to flatten the heads. I'll do the rebuilding myself.

This doesn't include port matching, I'll be doing that myself as well.
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  #38 (permalink)  
Old 06-15-2012, 11:02 AM
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By matching heads to the intake is not port matching. When you mill .030 or more from the heads, the intake gasket surfaces need to be altered to seal. Angle mill or none.

If somebody is portmatching for 25, he is not very good. You can do a fine job yourself. This is the engine to learn on too.
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  #39 (permalink)  
Old 06-15-2012, 11:40 AM
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When you mill .030 or more from the heads, the intake gasket surfaces need to be altered to seal. Angle mill or none.
What is altered on the gasket surfaces? What do you mean by "Angle mill or none?"

Sorry, I'm VERY new to this. If it's not on google or in 1 of 3 books I have, I probably don't know about it.
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  #40 (permalink)  
Old 06-15-2012, 03:05 PM
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Changing , milling the heads down to increase compression changes the intaket gasket surface alignment. The distance and angle between the intake gaskets is now different. to keep from a incureable intake leak the intake must be surface matched,depending on the amount of head mill.

You can flat mill a head or angle mill a head. Angle milling can get more compression with less cut material and some cases is the best way.

Either way hand ovewr the intake you are going to use and have them mate it to the new cut heads.
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  #41 (permalink)  
Old 06-15-2012, 05:27 PM
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Now I know the difference between angle and flat mill. Sweet!

I still fail to understand what needs to be done to the intake. Let's assume a minimal flat mill to simply give me a flat surface, I should have plenty of compression without any extra milling done.
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  #42 (permalink)  
Old 06-16-2012, 10:52 AM
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I will not try to figure your compression.

When you have heads freshened at the shop they take thousans off . only enough to true the head gasket surface. You need to give them special instructions for milling .030-.060-.090 what ever off and costs extra. Unless you are Hector at NAPA.

Heads flat milled down .030 need about half that take from the head intake side. Sometimes even the intake itself. So it is a good idea to have the intake avalible for mating even for clean up cuts.

If you can cut the heads on a angle to specifically to decrease the combustion chamber it leaves more material for structure integrety. So basically better. This is even more complicated for matching the intake surfaces.

All clear now?
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  #43 (permalink)  
Old 06-16-2012, 01:28 PM
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Makes perfect sense. Thank you!
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