Speedmaster Small block porting tips and results Part 1

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When back and look at some of the stock chamber posted up and Yup there the same as the CNC chamber it that area.
The CNC chamber just jumps out and you and says"LOOK AT ME LOOK AT ME!!!!:wtf:
I'm with PRH sInk that intake valve and get some top cut.!!!!
I guess we will see when PBR get some cfm going thru them heads.

ou812 said:
Watch how much the air speeds up when working the chamber. Also, if you leave slight ridge and don't blend the chamber into the top cut, you can slow down the reverse flow. Then bring the flow in good after .250 lift. Helps power production down low. I get better flow with less work using the SM castings. They also have more metal in them in certain spots than the eddy heads allowing for better shaping of things. The throat is large enough to go to a 2.055 intake valve also, only needs a slight increase to get that 90%.
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That's starting to make more and more sence to me.
 
yellow rose said:
It's not the diameter of the spring. The geometry is wrong and if you fix that, the interference goes away.
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How were you fixing/ tailoring the geometry in 1981. and don't tell me you were machining the stands
 
I will hopefully have some intake and exhaust flow numbers tomorrow. I went to a Catholic funeral today and brunch after so that was a 5 hour thing. Then I went to see a very good Mopar Racing buddy that is fighting some health issues. 44 plus years of racing together and we both port heads and build engines so we had lots to bs about.
 
Cudafever said:
When back and look at some of the stock chamber posted up and Yup there the same as the CNC chamber it that area.
The CNC chamber just jumps out and you and says"LOOK AT ME LOOK AT ME!!!!:wtf:
I'm with PRH sInk that intake valve and get some top cut.!!!!
I guess we will see when PBR get some cfm going thru them heads.



That's starting to make more and more sence to me.
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Good. Had me worried for you.
 
PBR, I'd be very interested in your opinions on a GOOD valve job, as in angles, contours, and sizing, I think it would add to this allready EXCELLENT discussion! Thank you so much for sharing your knowledge!
 
replicaracer43 said:
PBR, I'd be very interested in your opinions on a GOOD valve job, as in angles, contours, and sizing, I think it would add to this allready EXCELLENT discussion! Thank you so much for sharing your knowledge!
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Thanks for the thanks but our other members that are contributing to this posts can answer valves angle questions better. I’m locked in th only being able to do old school 60-45-30-15-10 type of fixed angles. The Edelbrock and Edelbrock copies suck azz in the chamber but respond well to a 15 degree top cut. I hope the other guys chime in on this to help you more.
 
pittsburghracer said:
Thanks for the thanks but our other members that are contributing to this posts can answer valves angle questions better. I’m locked in th only being able to do old school 60-45-30-15-10 type of fixed angles. The Edelbrock and Edelbrock copies suck azz in the chamber but respond well to a 15 degree top cut. I hope the other guys chime in on this to help you more.
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What are you using to cut your seats?
 
On the intake I'd do a 30° to 35° top cut around .08 wide a 45° .04 wide seat with a 65° bottom cut. The somewhat narrow seat in conjunction with the steeper bottom angle will allow the bottom cut to gain some much needed width.

The VJ would have to be sunk some to accomplish this, but it would improve the mid lift #s a ton.
 
If the goal was increased low lift flow, from like closed to .450 or so max, would the valve job strategy be any different?
 
Just lap the intake valves in on that VJ, then back cut the valves to within .015 of the lap mark on the valve.
 
Question for Pittsburghracer. Are you tubing the head bolt and push rod hole just so when you hit copper you know to stop cutting?
 
PBR..do you drill for the tube then grind till it breaks through then install tubes or install tubes then grind till you hit the tube.
 
Well if you would look at my pinch measurements on around page 15 you will see Stock was .930, cnc’d was 1.015, and tubed was 1.040 kissing the tube. There really isn’t much safety room on the cnc’ heads (.025) which isn’t much when you consider core shift pouring heads and machining them. Personally I think I would tube the cnc’d heads if it was me. One 10 inch stick of 17/32 K&S tubing, a tubing cutter, and some JBWeld and you’re good to go.
 
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