Well it's about time!
You could borrow my project 500 AVL head, it's still sitting on the bench after being drilled and tapped for an iron engine decompressor. Bullet Whisperer has even fitted some comp valve springs, only trouble is, it's on the wrong side of the Pond for you guys! Plus it has already been ported, possibly rather differently to what you might have been planning.
The head is a lovely design, and with all BW's work on cam selection and compression hikes already giving good results with a stock head casting, the thought of a Mandello-quality AVL head is very tempting. The quality of the stock port work, particularly where the valve seats are fitted, will NOT make your day...
I'd also be intrigued to know what cams and carb you're planning to use if it's not a trade secret!
Regards,
Adrian
Hi Adrian,
Yes, we'd like to have a fresh unmodded head to work on, so that we can have a baseline for doing other ones.
The things we'd like to do revolve around getting the valve open further, and controlling the valve spring oscillations, which I am betting can be done with our Ace valve gear. I have some high-ratio roller rocker arm work being done on a Hitchcock's Iron Barrel Big Head which has that similar type of rocker boxes and rocker shafts in it. It's not complete yet, but it should be done soon, and I could do a similar thing in the rocker boxes of the AVL.
That would give us the valve lift, which is so desperately needed with that shape combustion chamber. And it would get us around the cam problem, and I expect that our beehive spring kit with lightweight titanium retainers would overcome the valve spring issues that prevented higher revving. We could use the "S" cams if desired, or the stock AVL cams, or whatever cams we wanted to put in there. With the ratio rockers providing the lift multiplier, that can turn our .300" lift cams into .450" lift cams, or whatever ratio we pick.
Also, we have recently worked on a new porting job which is larger, and has an inlet port shape that is somewhat reminiscent of the stock AVL port shape, and has some very good port speed, using some specialty techniques. We may be able to apply these techniques to the AVL port, and I'm interested in getting an AVL head on the flow bench to see just what we could do with it.
I feel quite sure now that if we can get our valve gear into this head, and put some ratio in the rockers for increasing lift, and get any reasonable improvement in the port and valve seat area, we can get a good gain out of this head.
I'm confident enough about it now, to seek a "guinea pig" to give it a go.