B1 Original Vs B1 MC

Posted By: Bob_Coomer

B1 Original Vs B1 MC - 09/23/11 07:10 AM

How can you tell the diff between the two? What part number is P4349600? I see on the end of the head it says MC...
There is a casting on the end of the head also of B970..

Posted By: Bob_Coomer

Re: B1 Original Vs B1 MC - 09/23/11 07:11 AM

Also is the pistons diff between the two?

Posted By: Al_Alguire

Re: B1 Original Vs B1 MC - 09/23/11 02:46 PM

Not sure on the part number thing. The difference is the intake valve is moved slighlty to allow for a bigger intake valve. In terms of flow from what I have seen there is about a 30cfm difference between the two heads.

Posted By: Bigcube

Re: B1 Original Vs B1 MC - 09/23/11 03:48 PM

No B1 expert here but I thought they were the same casting, they just machined the valve location in a different spot.

Posted By: MR_P_BODY

Re: B1 Original Vs B1 MC - 09/23/11 04:13 PM

I would believe that the valve pockets in the piston
is bigger for the 2.4" valve in the M/C head... normally
you run .1 bigger than the valve so the pocket would
be 2.4 for the B1 original and 2.5 for the M/C... same
castings with the M/C intake moved .050(I believe it is)

Posted By: BIGSPEED

Re: B1 Original Vs B1 MC - 09/23/11 06:47 PM

The exhaust valve is moved .050 towards the wall to allow a .100 larger intake. Center punch the piston down the guide at 10 degrees before or after. Use a compass to sweep the reliefs you have to see where you are at. Set compass at half valve size. If you have B-1 pistons in it you may not have to do much to the reliefs if the piston manufacturer was a little generious with his cutter. Frank

Posted By: MR_P_BODY

Re: B1 Original Vs B1 MC - 09/23/11 07:08 PM

Quote:

The exhaust valve is moved .050 towards the wall to allow a .100 larger intake. Center punch the piston down the guide at 10 degrees before or after. Use a compass to sweep the reliefs you have to see where you are at. Set compass at half valve size. If you have B-1 pistons in it you may not have to do much to the reliefs if the piston manufacturer was a little generious with his cutter. Frank

Its the exhaust that moves... thanks for that info...
I thought it was the intake... I sold my B1M/C heads
so I dont have them anymore to look at

Posted By: Bob_Coomer

Re: B1 Original Vs B1 MC - 09/23/11 09:24 PM

Quote:

Quote:

The exhaust valve is moved .050 towards the wall to allow a .100 larger intake. Center punch the piston down the guide at 10 degrees before or after. Use a compass to sweep the reliefs you have to see where you are at. Set compass at half valve size. If you have B-1 pistons in it you may not have to do much to the reliefs if the piston manufacturer was a little generious with his cutter. Frank

Its the exhaust that moves... thanks for that info...
I thought it was the intake... I sold my B1M/C heads
so I dont have them anymore to look at

I was told By Scott Koffel to be able to reuse the MC rockers with Original heads, the exh rocker needs to be moved .040 towards the intake valve. So I assume the intake is moved away from the intake towards the wall? to allow the larger intake valve?