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  #16 (permalink)  
Old 09-12-2013, 04:08 PM
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A GOOD aluminum head is always better.However,I'd rather run an iron Vortec before I'd use a crappy built aluminum.Keep in mind tho,IF you do run Vortecs(L31),they do need a Vortec specific intake & you will need steam holes for a 400.

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  #17 (permalink)  
Old 09-12-2013, 04:14 PM
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I agree with most of what 40fordRob said, with the exception of pulling a camshaft out of thin air. A builder cannot intelligently choose the proper cam until he matches the cam grind to the static compression ratio. So, if you don't know the static compression ratio, you will have to figure it out mathematically. I can teach you how.

Current thinking caps the static compression ratio at about 9.5:1 for iron heads and 10.5:1 for aluminum heads, so that the motor can operate without detonation on the available pump gas today. And like I said, once you have nailed down the static compression ratio, you have the knowledge to choose the proper camshaft.

Motor oil formulations have changed dramatically in the past few years. Oil companies have been forced to eliminate extreme pressure lubricants such as zinc from off-the-shelf motor oils due to political pressure from the automobile manufacturers. Extreme pressure lubricants in the motor oil find their way into the exhaust pipe (every motor burns a little oil, whether or not you can see it in the exhaust) and clog up catalytic converters, costing the auto manufacturers money to replace the converters under new car warranty.

Flat tappet camshafts, which used to be the norm for manufacturers, have been replaced with roller tappet camshafts because flat tappet camshafts cannot live without extreme pressure lubricants. This should be your first clue......DO NOT BUILD YOUR MOTOR WITH A FLAT TAPPET CAMSHAFT unless you intend to use aftermarket oil additives containing extreme pressure lubricants. Please read and heed this tutorial....
http://www.crankshaftcoalition.com/w...ips_and_tricks

I very strongly urge you to consider using a Howards retrofit roller hydraulic cam and lifter kit. They are priced under 600 bucks. See some of their offerings here....
http://www.summitracing.com/search?k...rder=Ascending
There are no hoops to jump through for installing these cams. You simply wash off the anti-rust preservative with solvent, oil the parts, install, adjust the valves and run. There is no break-in procedure involved, so no need to run weaker valve springs for the break-in like you would with a flat tappet cam.

How I would do it, using iron heads and a ~9.5:1 static compression ratio cap.....
First, add up the "stack" dimension you will use. Add half the stroke (1.875" in this case), the rod length (I would use 5.7 rods to keep the wrist pin out of the oil ring groove on the pistons) and the piston compression height (~1.425")....
1.875 + 5.7 + 1.425 = 9.000"
Verify main bearing bores for round and parallel. Correct as necessary. Cut block decks to 9.000" block deck height, leaving zero piston deck height. Use a compressed head gasket thickness of 0.039" to 0.040" to establish a 0.039"-0.040" squish with zero deck.
Use dished pistons to arrive at a ~9.5:1 static compression ratio with the heads you will use.
64cc chambers with a 22-24cc dished piston.
65cc chambers with a 21-23cc dished piston.
66cc chambers with a 20-22cc dished piston.
67cc chambers with a 19-21cc dished piston.
68cc chambers with a 18-20cc dished piston.
69cc chambers with a 17-19cc dished piston.
70cc chambers with a 16-18cc dished piston.
71cc chambers with a 15-17cc dished piston.
72cc chambers with a 14-16cc dished piston.
73cc chambers with a 13-15cc dished piston.
74cc chambers with a 12-14cc dished piston.
75cc chambers with a 11-13cc dished piston.
76cc chambers with a 10-12cc dished piston.

Heads with a 170-180cc intake runner will produce gobs of low end torque, running out of breath over 5000 rpm's. Smallish runners like this make an extremely pleasant daily driver with excellent throttle response and decent mileage. Use an Edelbrock Performer RPM spreadbore intake manifold mounting a 750/800 cfm Rochester Quadrajet carb, dialed in for your particular application by Ruggles and a set of 1 5/8" long-tube headers with an H or X pipe before the mufflers. Mount a 14" x 4" air cleaner assembly on the Quadrajet. The motor cannot breathe through a tiny little air cleaner.

Using a ~9.5:1 SCR, you'll want a cam that closes the intake valve at somewhere around 35 degrees after bottom dead center. Here's an example of a cam that I might choose to use with such a motor for street and highway driving......I'm not saying to buy this cam, I'm just showing you some specs that would work well with a 9.5 SCR......
Crane 119671
Excellent low end and mid-range torque and HP,good idle, daily usage, offroad, performance and fuel efficiency, 2600-3400 cruise RPM, good w/small plate nitrous system, 8.75 to 10.5 compression ratio advised. 0.900” base circle for long stroke clearance.
Grind number HR-216/339-2S-12.90 IG
Operating RPM range 1600-5800
Advertised duration 284/292
0.050" duration 216/224
Valve lift 0.509"/0.528"

By the way, here's a tutorial of how to drill the steam holes in the heads......
http://www.gregsengine.com/convertin...ds-to-400.html

Last edited by techinspector1; 09-12-2013 at 04:30 PM.
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  #18 (permalink)  
Old 09-12-2013, 05:27 PM
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If you do 0 deck the block & go with the 5.7" rod,be careful to make sure your pistons have the 1.425" pin hgt.They also make a 1.433" pin hgt piston as well.This would be too tall with a 0 decked block.
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Old 09-12-2013, 05:33 PM
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100% correct joker. Determine the stack first, then cut the block. Thanks.
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Old 09-12-2013, 08:47 PM
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build the engine to the performance level you want.You dont need to compare random parts. I wouldnt build much over 500 HP in a stock,old,antiquated block.
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Old 09-13-2013, 12:01 PM
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Originally Posted by vinniekq2 View Post
build the engine to the performance level you want.You dont need to compare random parts. I wouldnt build much over 500 HP in a stock,old,antiquated block.
I'm not lookin to make that much power just lookin to beef the motor up a lil give it better top end
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  #22 (permalink)  
Old 09-13-2013, 02:09 PM
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You can tolerate a more compression by 1 point because aluminum heads and will produce less BTU then cast iron heads. It will release excess heat built up in the engine. It will make the 406 run a little cooler.
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Old 09-13-2013, 03:39 PM
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Originally Posted by lg1969 View Post
You can tolerate a more compression by 1 point because aluminum heads and will produce less BTU then cast iron heads. It will release excess heat built up in the engine. It will make the 406 run a little cooler.
Heads do not produce BTU's.

Aluminum is a better conductor of heat. It is able to transfer heat from the combustion chamber to the water jacket much better than iron. Now that the combustion chamber is cooler, you MUST INCREASE compression to get that heat back up to have an efficient running engine. If you were to swap iron for aluminum and keep the CC's the same, you would be leaving power on the table. The other advantage to aluminum is the fact that it is lighter (which makes your car faster and handles better).

Also, not any head gasket is going to work with aluminum heads. Do some research and if you go with aluminum heads, post back for suggestions. Again, 0 decking your block is going to pay off big here as now you can step up to a nice .039" or .040" gasket.
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Old 09-13-2013, 04:04 PM
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Your right, the combustion chamber generate BTU in a form of heat.
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Old 09-13-2013, 04:09 PM
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Man all these years I have been burning fuel to generate BTU's to make heat.

I'll put a chunk of aluminum in my living room this Winter and see if the house gets warmer.
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Old 09-13-2013, 10:27 PM
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what SS said,the BTUs are the heat available in the fuel when burnt.Propane has less BTUs than Gasoline and diesel has more BTUs than gasoline.It does not matter where you burn the fuel.

back to power required? how much power do you require? or in your case,how much "beef" do you need? I like beef,,,
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Old 09-13-2013, 11:08 PM
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Originally Posted by vinniekq2 View Post
what SS said,the BTUs are the heat available in the fuel when burnt.Propane has less BTUs than Gasoline and diesel has more BTUs than gasoline.It does not matter where you burn the fuel.

back to power required? how much power do you require? or in your case,how much "beef" do you need? I like beef,,,
The motor stock has about 265 horses I would like to get around 350 to 400
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  #28 (permalink)  
Old 09-14-2013, 10:08 AM
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most heads will flow enough for 350 plus hp.you need to have a little over 9:1 for cast heads and 10:1 for aluminum heads.RPM or better intake,750 CFM carb,mild 220 roller hydraulic cam,long tube headers.(I would use 1 3/4 primary tubes)free flow exhaust with X pipe.
exact compression ratio and cam choice(matched) will determine the power.
for more power buy good heads
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Old 09-14-2013, 02:00 PM
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Wring out every dollar you spend for the street and build towards low end torque and say the hell with HP.Not talking about a tractor pull engine but off idle on where these 400's like to perform.
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Old 09-15-2013, 06:35 PM
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Originally Posted by F-BIRD'88 View Post
Start by id'ing the cylinder heads you got. Look under a valve cover for the casting number. What is it?
The casting numbers are 3998997 are these heads anygood 76cc 1.94/1.50 valves
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