335 HP 396 290 Head Casting Build & Dyno Test

[Mark Yacavone]

Originally Posted by goinbroke2

For us crayon eaters in the class, can you explain the pictures in better detail please?
I understand you want all the valve heads the same height in the chamber so with sunk seats, you're replacing the seats and getting all the heads to sit at the same height...got it. But in the picture where you say you have .060, you're measuring from the deck height and what? I can't see but I'm assuming you're going to the top of the seat you installed?

Once all valves are sitting in the same place in the chamber, the cc's should be closer to start with...am I on the same page or in left field?

60 is the degree cut in the seat, that didn't exist before. This is a good part of the low and mid flow pick up.

[HP HUNTER]

OK- the valve job is 30/45/60/75/90 on a BBC production head the valve bowl is too big to get much if any 60 degree angle with a 2.065 valve. In the picture you will see the lap line, below the lap line is the 60 degree angle which is around .180 wide, that 60 degree angle is partially responsible for the low lift flow gains. If you look at the picture before modifications you will see there is very little 60 degree angle below the 45 degree seat. Hope that explains it.

[MAURICE BLENDHEIM]

Originally Posted by HP HUNTER

A while back I was looking for a transmission and came across a complete 335 HP 396 Stocker drive train for sale and and bought it. From what I've been told this engine/trans ran 3-5 tenths under the index in D/SA trim, dyno data also came with the engine which I will share as well. My plan is to go through the 290 head castings and see if I can make some improvements then dyno test the engine and finally run it in the car. I tore the heads down and preliminary cleaned them for a flow test, which I will post as the car ran 3-5 under the index. I will be testing the other head as well before any work starts to make sure it's similar in flow to the first head tested.

Mark… I am really looking forward to the results. As per our previous discussion it should be interesting. Maurice

[HP HUNTER]

Originally Posted by MAURICE BLENDHEIM

Mark… I am really looking forward to the results. As per our previous discussion it should be interesting. Maurice

Great, happy to have you involved. More pictures

[HP HUNTER]

Exhaust flow is now:

.200 126 + 19
.300 160 + 29
.400 175 + 23
.480 178 + 13

Exhaust valve is tullipped.

[HP HUNTER]

Ready to be cleaned and assembled.

[goinbroke2]

If you don't mind sharing, how wide is the seat and how wide are the other angles?

Thanks

[HP HUNTER]

Originally Posted by goinbroke2

If you don't mind sharing, how wide is the seat and how wide are the other angles?

Thanks

The intake seat is .045 wide, The exhaust is .065 wide, I will have to measure the other angles widths and get back to you.

[goinbroke2]

Hmm, narrower than i thought. I kept exh seat a bit wider to help heat dissipation (.070)
And then I did the same for intake (.070) and the others were kept to whatever it took to put the seat (45) where i wanted it so the 30 and 60 vary from .030 to .07.

Am i on the right track or did i mess up?

[HP HUNTER]

Originally Posted by goinbroke2

Hmm, narrower than i thought. I kept exh seat a bit wider to help heat dissipation (.070)
And then I did the same for intake (.070) and the others were kept to whatever it took to put the seat (45) where i wanted it so the 30 and 60 vary from .030 to .07.

Am i on the right track or did i mess up?

Can you post a picture? I don't think I'am qualified to answer that question, .005 extra width on a seat I wouldn't think would make or break you.