kaase boss 9

-building a new motor going to be a 638 on alcohol. was going to go with a set of c460 heads, but started to winder if the kaase boss 9s with support the cubic and the .850-.900 lift ill be running, tried to do some research but couldnt find any flow numbers and or any support showing they would. would love to but a badd ass boss motor in my new build. or am i better off just style with the wedge head?

what could the the boss heads flow and support on a max effort deal?

I have ported and flowed a few sets of Kaase Boss Nine heads. While they are much better than the original 429 Boss heads, they are still more of a restoration type of head with the port entries and exits in the original location, as Jon intended by design. In fully ported form their flow numbers are about the same as a good fully ported TFS A-460 head. So if I were you and needed to run the Boss Hemi style head for the appearance sake, then to feed your 638 on alcohol, I would step up to the Boss A-441 head or the B-441 head that Carroll Carter sells. However, if you are thinking in terms of a full race Pro Stock wedge head for your 638, then the choices would be the C-460, or ProFiler 205 & 221 heads, or Thor head (which is no longer in production), or the Pro 18 head and Visner billet head.
Hope this helps, Charlie

there is an old post on here that showed a flow chart of 523 on intake.it was kaase heads,but had a high port intake mod,that raised the port opening a bunch.wayne gapp use to do that on the original ford heads,using a aluminum block in the bottom of the port with epoxy to seal it. the a441 heads have a raised port as well,about as high as it can go.
,just below valve cover rail.i would think you would need the c and c  a441 heads to make 1200 plus.or you could use the sr71 headsas kaase posted here a while back.

hbstang wrote:there is an old post on here that showed a flow chart of 523 on intake.it was kaase heads,but had a high port intake mod,that raised the port opening a bunch.wayne gapp use to do that on the original ford heads,using a aluminum block in the bottom of the port with epoxy to seal it. the a441 heads have a raised port as well,about as high as it can go.
,just below valve cover rail.i would think you would need the c and c  a441 heads to make 1200 plus.or you could use the sr71 headsas kaase posted here a while back.

Years ago, when I was strolling through Ford Power Parts in Norwalk, Calif. on Carmanita Ave.(remember that place? ) there was a set of Boss heads that were radically modified. The top of the intake ports were raised so much, they were actually protruding up into the valve cover area. Extra aluminum had been welded and built up , then the ports were opened up way up into the raised area. The valve covers were modified and 'notched' to go over this area. I could not understand at that time why somebody would butcher up a set of heads like that, and it kinda upset me! LOL.
Now I know why it was done!

This is what Kaase and the boys can get out of a more race orientated Max effort High Port Deal..
Though it is ALOT of work and expensive but it is an option..

I have to agree with Charlie and hbstang the A441 head is a great option for your cubic inch and Alcohol..
If your heart is set on a Boss Hemi style head.

below is a stock low port entry Kaase Boss9 head.. and a highly modified by Kaase High Port entry deal..that head flows 514 @ .700" 523 .800" lift.

With a ported Kaase single carb manifold 598ci race deal has gone 1156hp (.800"lift cam) and a 611ci i believe went 1172hp on kaase's dyno..

A sheetmetal and twin carbs 1200+hp should be easily possible..  

i wish kaase would make thaose as cast,with matching intake.
TM boss heads have that option.
did they weld the bottom of the port up?

Yes they did weld up the bottom of the ports and the water cross overs..also needs adaptor plates to lift the intake manifold up.

That particular head has 55 degree seats and a bigger 2.450 intake valve to help achieve those 523cfm intake flow numbers.

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Rickytx630 wrote:-building a new motor going to be a 638 on alcohol...started to wonder if the kaase boss 9s with support the cubic and the .850-.900 lift ill be running, tried to do some research but couldnt find any flow numbers and or any support showing they would...

You might want to call over to Kaase's shop and make sure his Boss heads can even accommodate 0.900" lift in the fist place, because the way I would set up such a head would be with long valves and big triple springs and as I see it you will not be able to drop a valve cover atop those heads due to the exhaust valve stem tips and big radius springs overhanging the valve cover rail (interference).

You will not have this issue with the A441 heads, and they make more sense for your build (on paper anyway) in the first place. My vote is for them.

how much do you think a larger intake valve would help power/flow in a non hi port kaase boss heads?i didnt know a 2.450 valve would fit.i think mine came with 2.300 from kaase.

You would be best to talk to Kaase about how much increased flow /power could be achieved in a low port head.. it seems after talking to them 99% of the time they use a "2.40" intake valve...the 2.45 valve in my heads was only a one off deal..

The average flow numbers are a little better with the 2.40 valve i'm pretty sure you would have to change the seat inserts as well for the bigger 2.40 valve to work..i would also say the 55* degree seat angle and shape of the back of the valve, and of course the required bowl rework and porting would of also helped in achieving the 500+ cfm flow figures.

Whether they could achieve the same results with a low port head i don't know..

The Pro 18 head is basically the Thor Gen II head now sold by C&C Motorsports.

Totally killer head. I would go with the Pro 18 or the A441 that C&C sells.

Big power makers either one.

Good luck.

**I would also use BES to port them. They seem to be making as much power or more than anyone out there right now.