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  #31 (permalink)  
Old 04-29-2013, 12:42 AM
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I didn't say you were a fool gears, I was referring to myself. If I didn't know about small block pieces that could be interchanged there wouldn't have been a reason for me to reply at all as I would look like a fool doing so.
Let me try and explain this in more detail, this is another engine but the concept is still the same.
In 1994 and '95 Chevy released the L99, which was also referred to as the "baby LT1" it was a 265 cubic inch reverse flow cooled V8. It was the
LT1's baby brother.
Now, these engines came with rods that were PM, and measured 5.940 inches long. We take these rods, then find a 880 casting Vortec 350 Block, then get a 1 to 2 rear main seal adapter, then drop in a crank out of a 307
or if we get really lucky a large journal 327 crank. Next we have the block decked .010 and we use 383 Chevy pistons with a 1.425 compression height.
Slap it together and now we have a roller cammed long rod 327 engine with a rod to stroke ratio of 1.82:1.
As said, he is using the shorter 400 rod, yes, but he's also using a 283 piston.
As we know, all small block generation 1 engines used the 5.703 inch rod, except the 400. Chevy used the interchangeability to it's advantage and it was smart to keep the same rod length and just change the compression height of the piston. This kept costs down.
The 283 came with a 3.000 inch stroke crank, so the compression height on the piston is 1.800, the compression distance is measured from the center of the rod pin to the top of the piston.
The 307 as said has a 3.250 inch stroke, and it too used the same 5.703 rod.
The 307 was a merger of the 283 block and the 327 crank. All chevy did was discontinue the 283 in 1967. In 1968 they made the block into a large journal block, kept the bore size the same at 3.875, stuck the 327 crank in with it's longer stroke, then reduced the compression height of the pistons down to 1.675 and that was that. Since he's using the shorter 5.565 400 rods, he can use the higher compression height pistons of the 283 to compensate for the shorter rod. This practice is done as you can't get 307 pistons anymore that aren't "Rebuilder" pistons that have the shorter compression height and if these pistons were used with a 5.7 rod then the block would have to be decked to it's max plus use the thinnest head gasket available to give it some compression and quench action.

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  #32 (permalink)  
Old 04-29-2013, 04:00 AM
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If I use a .028 head gasket the ratio is 10.87:1, but my quench will be .058. That seems high for pump gas. I can still get 9.86:1 compression without milling the block and using flat tops.
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  #33 (permalink)  
Old 04-29-2013, 09:53 AM
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If you plan to use flat tops it would be a better idea as it'll lower the compression ratio enough to survive on pump gas.
With the overbore added in, head gasket, stock deck height, piston crown and stroke the ratio with 58cc chambers comes in around 9.7:1 which will work well on 93 octane as long as you have a good quench action.
Depending on how far down the piston is in the bore at TDC will judge the quench action. Lets say it's .025 in the hole at tdc. Then add in the head gasket thickness of .028 and we get .053 which isn't horrible. As long as it's under .060 your okay.
However if you were to use a thicker head gasket you'll lose quench action entirely and when the ratio is in the higher 9's you'll run into detonation problems unless the timing is set real carefully. A higher compression ratio is safer with a good quench action and without it the risk of detonation becomes greater.
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  #34 (permalink)  
Old 04-29-2013, 01:53 PM
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Quote:
Originally Posted by ss307 View Post
If I use a .028 head gasket the ratio is 10.87:1, but my quench will be .058. That seems high for pump gas. I can still get 9.86:1 compression without milling the block and using flat tops.
I have no idea why you seem so hell-bent on using a lot of static compression ratio in this motor. Current thinking puts the cap at 9.5:1 using iron heads and 10.5:1 using aluminum heads.
Using excessive SCR with iron heads will require that you pull all the ignition timing out of the motor to prevent it detonating itself to death and there goes all the power that you thought you were building by using a high SCR in the first place. Build it 9.5:1 with iron heads, use a cam with somewhere around 212 degrees intake duration @0.050" tappet lift, narrow lobe separation angle (108/110) for more power at the bottom, wider lobe separation angle (112/114) for more power at the top, 1 1/2" long-tube headers for good low end torque and horsepower in this small motor, 16 degrees ignition advance at the crank, 20 degrees centrifugal advance all in by 3000, stock converter and stock gears. 600 cfm vacuum-secondaries carb mounted on an Edelbrock RPM, Holley #300-36 or Weiand #8016 intake manifold.

Your combination of parts will never make a race horse, but it will make a good plow horse if you pay attention to detail.

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  #35 (permalink)  
Old 05-01-2013, 05:35 PM
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Hello DoubleVision,
Can you take a 350 4 bolt block and put in a 307 crank and 5.7" rods, That will basically make a 327 correct?
In doing so what pistons should be used with edelbrock heads to get max comp ratio for pump gas, flat tops?
What would the best distance be in the hole for the pistons? zero?

Kind regards


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Tres, the 307 came from the factory with the same stroke as a 327 which is 3.250. The 307 was created by merging the 283 bore and the 327 stroke.
Gearheads, the idea would be to use a piston with higher compression height to compensate for it, such as the pistons out of a 283. I used to keep up with all the tricks but since I never come across any 307's I didn't care to remember. When building a performance 307 there's one problem we run into and that is the pistons. The stock compression height 307 piston from the factory is 1.675. The hyper aftermarket pistons are 1.655, so as you see they whacked .020 off the compression height. The majority of cheapy "rebuilder" pistons are made this way. That is why we use the shorter rod and a 283 piston which has a higher compression height due to it's shorter stroke.
When you look at my post count I hope you realize I didn't start turning wrenches yesterday. I say that because if I didn't know by using a shorter rod would cause all kinds of deck problems I wouldn't even bother to be on this site and I sure as hell wouldn't answer any questions based on something I know nothing about and make myself look like a fool.
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  #36 (permalink)  
Old 05-02-2013, 03:30 AM
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Yes, You can throw a 307 crank in a 350 block and it makes a 327.
With 5.7 Rods you would use 327 pistons with the 1.675 Compression height.
It would depend on the combustion chamber size of the heads. If they are
64cc's a flat top design would work nicely on pump gas. If the heads are aluminum then you can run higher compression on pump gas due to aluminums ability to dissipate heat quicker.
You can even use the 307 crank in a 1 piece rear seal block, however you'll need the 1 to 2 piece seal adapter. However if you go this route with the
307 crank, I recommend you have the crank balanced since the 327 used heavier pistons than a 307.
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  #37 (permalink)  
Old 05-02-2013, 07:38 AM
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Quote:
Originally Posted by naphtali5725 View Post
Hello DoubleVision,
Can you take a 350 4 bolt block and put in a 307 crank and 5.7" rods, That will basically make a 327 correct?
In doing so what pistons should be used with edelbrock heads to get max comp ratio for pump gas, flat tops?
What would the best distance be in the hole for the pistons? zero?

Kind regards
You CAN go this route, but why?

To be different you may as well just go for the Chevy 302, for power there's no reason to not go with at least a 350. A well prepped mostly stock 350 short block can take more abuse than people realize, with sbc's the limiting factor is usually cam and valvetrain, NOT stroke.
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Old 05-02-2013, 11:27 AM
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Not trying to be different, just wondered if that is the route to go to get a 327 without being able to find a 327 block, since i don't seem to be able to find one...
I'm aware of a well built 350 being able to handle abuse, that's why everyone has one...


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You CAN go this route, but why?

To be different you may as well just go for the Chevy 302, for power there's no reason to not go with at least a 350. A well prepped mostly stock 350 short block can take more abuse than people realize, with sbc's the limiting factor is usually cam and valvetrain, NOT stroke.
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  #39 (permalink)  
Old 05-02-2013, 11:39 AM
How fast is fast enough?
 
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Quote:
Originally Posted by naphtali5725 View Post
Not trying to be different, just wondered if that is the route to go to get a 327 without being able to find a 327 block, since i don't seem to be able to find one...
I'm aware of a well built 350 being able to handle abuse, that's why everyone has one...
no, everyone has one because they're cheap. There are are many far better engine designs than the sbc, but they're not even close when it comes to price.
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Old 05-02-2013, 11:48 AM
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no, everyone has one because they're cheap. There are are many far better engine designs than the sbc, but they're not even close when it comes to price.
can you give an opinion of a better design... I have an Olds 455, and that thing is expensive to build...
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  #41 (permalink)  
Old 05-02-2013, 02:37 PM
How fast is fast enough?
 
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Originally Posted by naphtali5725 View Post
can you give an opinion of a better design... I have an Olds 455, and that thing is expensive to build...
Just about any popular engine designed from the late 70's on, and many before that.

My first engine was a 350 Olds- yet another case of a better design.

It really all depends on what you want, mileage, displacement, durability, etc. Plenty of options to choose from.
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  #42 (permalink)  
Old 05-02-2013, 05:58 PM
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better?

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can you give an opinion of a better design... I have an Olds 455, and that thing is expensive to build...
The LS engines are more powerful.Please say what would be better to you?
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  #43 (permalink)  
Old 05-08-2013, 07:43 AM
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I've decided to sell the 400 rods and use 5.7" Eagle rods with Keith Black 307 Flat Top Pistons(283 pistons have to high of a compression height to use with the 5.7 rods and the 307's 3.25 stroke). I'll have a 10:1 CR with the 416 heads. I'm using a Weiand 7504 intake and a Holley 600 CFM. What cam should I use? I can't make up my mind
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  #44 (permalink)  
Old 05-08-2013, 08:04 AM
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I would use a roller hydraulic with specs around 22o duration @050.The icl @104,,,,but I would try to lower CR to 9.5:1. .500 lift would work well and have good street manners
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  #45 (permalink)  
Old 05-08-2013, 12:04 PM
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I haven't heard much of Crower cams. How about a Crower 210HR215?

Basic Operating RPM Range: Idle-6,000

Intake Duration at 050 inch Lift: 212

Exhaust Duration at 050 inch Lift: 218

Duration at 050 inch Lift: 212 int./218 exh.

Advertised Intake Duration: 284

Advertised Exhaust Duration: 288

Advertised Duration: 284 int./288 exh.

Intake Valve Lift with Factory Rocker Arm Ratio: 0.462 in.

Exhaust Valve Lift with Factory Rocker Arm Ratio: 0.470 in.

Valve Lift with Factory Rocker Arm Ratio: 0.462 int./0.470 exh.

Lobe Separation (degrees): 110
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