Ported 416 heads
11-28-2010, 02:07 PM
#201
Re: Ported 416 heads
I have not done the math on that. If you are shooting for 58 cc chambers, I would look for something smaller to start with, it will take a fair amount of milling on these heads to get to 58 cc chambers which can create other issues. I would choose a piston that would supply the additional dome volume, rather than milling a lot off of the head. Milling would be my LAST choice if I could not make up the compression some other way. Not saying it CANNOT be done, only that it would be my LAST choice.
The 64cc chambers on these heads was a slight negative, however, I was able to reach my target compression ratio AND squish clearance without any milling. I wanted a VORTEC Chamber AND High Flow ports and larger valves in an OLD School "Non-Vortec" pattern head.
My targets were:
C/R => 9.5 to 1
Chamber type = VORTEC
INTAKE Port volume => 170-180 cc
INTAKE Valve dia. = 1.9375
Quench Clearance = .040 (ideal) - .045(max)
Valve cover = Perimeter bolts
No heat crossover and screw in studs were icing on the cake!
The 64cc chambers on these heads was a slight negative, however, I was able to reach my target compression ratio AND squish clearance without any milling. I wanted a VORTEC Chamber AND High Flow ports and larger valves in an OLD School "Non-Vortec" pattern head.
My targets were:
C/R => 9.5 to 1
Chamber type = VORTEC
INTAKE Port volume => 170-180 cc
INTAKE Valve dia. = 1.9375
Quench Clearance = .040 (ideal) - .045(max)
Valve cover = Perimeter bolts
No heat crossover and screw in studs were icing on the cake!
11-28-2010, 09:33 PM
#202
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Re: Ported 416 heads
Like stated above, I wouldn't mill the heads down that much to increase the compression
When you mill the heads, you start to create issues. Like messing up the angles for the intake manifold gasket (gotta get the intake surface milled too), plus incorrect pushrod length. Milling .030" is fine, but more than that & it starts being a lot of trouble. Not to mention that you can increase valve shrouding as well
When you mill the heads, you start to create issues. Like messing up the angles for the intake manifold gasket (gotta get the intake surface milled too), plus incorrect pushrod length. Milling .030" is fine, but more than that & it starts being a lot of trouble. Not to mention that you can increase valve shrouding as well
11-29-2010, 11:49 AM
#203
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Re: Ported 416 heads
To clarify, you can safely shave .030" without the issues with the intake surface and pushrods being a problem, I did that on my 355 actually. But any greater, say .050", and you'll need new custom length pushrods & you'll need to mill the intake gasket surface as well
11-29-2010, 12:26 PM
#204
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Car: 1985 El Camino SS, 2004 Trailblazer
Engine: Hybrid 305, 91 SD TPI, lots of mods
Transmission: 200-4R
Axle/Gears: 3.42
Re: Ported 416 heads
IMHO, I would not use these heads if you were not doing a complete engine. The combination of the large chambers and your pistons would lower the compression. Too much milling would be required on the heads and intake as well. You would be better off with a small chamber, 305 specific head, even if you paid more for it. These heads are only cheap if you can use them as is. Why mill a brand new head on a stock engine? That just creates a whole bunch of other issues! Makes no sense to me.
EQ (and others) offer several VORTEC style 305 heads with 58cc chambers that would give the compression you want without all that milling. The EQ Vortec Hybrid head worked for me ONLY because I was doing a complete engine and had the option of choosing different pistons to make up the difference in compression caused by the increased chamber volume.
Good Luck!
11-29-2010, 12:37 PM
#205
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Car: 1985 El Camino SS, 2004 Trailblazer
Engine: Hybrid 305, 91 SD TPI, lots of mods
Transmission: 200-4R
Axle/Gears: 3.42
Re: Ported 416 heads
IMHO, I would not use these heads if you were not doing a complete engine. The combination of the large chambers and your pistons would lower the compression. Too much milling would be required on the heads and intake as well. You would be better off with a small chamber, 305 specific head, even if you paid more for it. These heads are only cheap if you can use them as is. Why mill a brand new head on a stock engine? That just creates a whole bunch of other issues! Makes no sense to me.
EQ (and others) offer several VORTEC style 305 heads with 58cc chambers that would give the compression you want without all that milling. The EQ Vortec Hybrid head worked for me ONLY because I was doing a complete engine and had the option of choosing different pistons to make up the difference in compression caused by the increased chamber volume.
Good Luck!
03-01-2011, 11:03 AM
#206
Supreme Member
Re: Ported 416 heads
Just for info reference the 1094 shim gasket works fine on 305's
|When eliminating the exhaust rotators, shim the exhaust spring seats with a .105" stack of shims .060+.030+.015" stack. to get a near 1.70" installed spring height.
The intake ports seemingly measure big cause of the big space in the roof of the intake port under the rocker stud. This big space is not in high perf heads like the old 461's etc.
The intake ports flow a bit better if you fill that void in the roof of the port with epoxy. This make the finished port smaller too. about 170+/- ported.
Filling the twined exhaust egr passages ( with aluminum or cement or...) stops adjacent cylinder exhaust port cross talk the headers scavenge better.
Worth more than you'd think on a racey motor with these heads.
This car needs 4.10 to 4.56 gears and a 8"-9" 4000 stall converter.
This lil 305 is going to want to rev.
Good job...
|When eliminating the exhaust rotators, shim the exhaust spring seats with a .105" stack of shims .060+.030+.015" stack. to get a near 1.70" installed spring height.
The intake ports seemingly measure big cause of the big space in the roof of the intake port under the rocker stud. This big space is not in high perf heads like the old 461's etc.
The intake ports flow a bit better if you fill that void in the roof of the port with epoxy. This make the finished port smaller too. about 170+/- ported.
Filling the twined exhaust egr passages ( with aluminum or cement or...) stops adjacent cylinder exhaust port cross talk the headers scavenge better.
Worth more than you'd think on a racey motor with these heads.
This car needs 4.10 to 4.56 gears and a 8"-9" 4000 stall converter.
This lil 305 is going to want to rev.
Good job...
Last edited by F-BIRD'88; 03-01-2011 at 11:14 AM.
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