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OHV 4 & 6 bangers! 6 cylinder talk & Q&A!

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Old 07-21-2017, 08:56 PM
bob w bob w is offline
Still crazy after all these years!
Join Date: Jan 2008
Location: Stillwater, MN
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Tom, When I put screw in rocker arm studs in my head I had the shop leave the stud boss untouched. Figured that would match up with the longer Chevy valve stems. I was wrong. I couldn't use BBC rocker arms and in order to get proper rocker arm geometry I used custom length Smith push rods and Sharp aluminum standard ratio rocker arms. I also had to raise the roof of the valve cover to fit it all in. I think cutting the stud boss .250" would avoid the problems and expense I incurred.
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Old 07-22-2017, 09:58 PM
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old28 old28 is offline
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Join Date: Aug 2009
Location: Camarillo, Ca
Posts: 320

Bob w, thanks for the information. Were you heads the early style with pressed in 3/8 studs or the late EFI pedestal type like mine?

Another thing, I am not sure that 1.94 intake will fit my heads. I may have to settle for 1.84 intake as the fast burn wall are very close to the intake out side edge. Not really worried about push rods as I will be running SBC adjustable guide plates and the push rods need to be heat treated. I think I will run thicker wall 5/16 rods like you have.

As I stated before this motor is a 1992 with .325 deep dish pistons but the piston to deck is only .021. The heart shape heads are 69cc and Ford rated the motor at 8.8 CR. I am going to replace the pistons with some 352 V8 units milled flat so I have a deck of .055 for a 10.0 CR.

Nice to finally get started on the build.
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Old 07-23-2017, 08:38 PM
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old28 old28 is offline
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Location: Camarillo, Ca
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This is from my thread over on Ford 6 site

Please take a look at the picture of the head chamber with the stock 1.775 Intake valve in place. I am not sure there is enough room to mount a 1.94 intake valve in the head as it is now. I do not want to do a lot of chamber machine work. I am thinking that may have to go to a little smaller 1.84 Intake. Take a look at the picture and see what you think. If I can do a 1.94 that is what I want. I will haul the head over to my machinist next week for him to take a look at.

member reply --

There should be room for a 1.94" intake valve.
Bolt the head back on the block and scribe the cylinder bore on to the head surface.
That will show you how far you can grind the chamber walls back away from the intake valve.
Also grind the radius back that is on the quench pad (Flat area) while still keeping the heart shape.

This is one of my 300 heads where I ground the walls back for a 2.02" intake valve.
You can see the circular scribe line.
https://www.dropbox.com/s/9dpif5xrxob8g ... 0.JPG?dl=0
Yes it is different than the EFI head but will give you a visual to work with.

This is usually where comments come in about messing up the quick burn swirl feature of the EFI chamber.

my reply ---

Thanks for the information and the picture. I will mark the head before I run by the machine shop so he can see what I have in mind. This whole motor build, piston, head, cam, valve train will be way different than Ford had for an EFI with quick burn. The 194/160 valves, crower 19205 cam, flat top pistons and 10.0 CR will make up for any mods to the head chamber.

This is what is fun, building something different with a plan on were you want to end up.
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Old 11-15-2017, 11:30 PM
Sunnybeach Sunnybeach is offline
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Join Date: Sep 2011
Location: Ann Arbor MI
Posts: 258

Any updates on this one?

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Old 12-04-2017, 05:49 PM
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old28 old28 is offline
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I have changed direction on the Ford 300 4.9L motor as this is my first shot at a Ford six. I have done three Chevy 6 motors 194", 250", 292" in the past but this 300 is a little different and I am learning along the way.

Been picking up parts for the last few months and should be getting head & block to the machine shop in January.

The revised motor spec's are as follows:
Bore & stroke -- 4.030" x 3.98"
Piston Type -- 4.030" Hypereutectic D-dish 22cc
Block will be -0- deck (.021" milled off)
Compression Ratio -- 9.3
1992 EFI fast burn chamber head
Mild port & polish
1.84" & 1.60" Chevy In/ex valves
Comp Cam 903 valve springs
RV performance cam
7/16 screw in rocker studs
BBC 1.7 roller rockers
Offy dual port intake
500 CFM carb
Electronic distributor

Will try to add pictures as the build progresses.
Attached Images
File Type: jpg 300 Motor 4.JPG (97.9 KB, 13 views)
File Type: jpg 300 Motor 15.JPG (106.7 KB, 16 views)
File Type: jpg 300 Motor 16.JPG (102.2 KB, 15 views)
File Type: jpg 300 Motor 30.JPG (119.4 KB, 14 views)
File Type: jpg 300 Motor 35.JPG (53.4 KB, 14 views)
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