I will check for you after the revalve job. I am putting in nitrided 214N stainless one piece for more durability over the titanium valves. I will not run it up as high as it was running before probably keeep it to 9000 -9500 rpm with the new valves due to increased weight.

We are also doing different transitions from stem to head on the new valves as well to try and crib a bit more flow. Chambers are also being recut with to improve seat to chamber radius.

Quote:

Yella Terra also do a 1.5:1 unit as well

how many ml's of liquid do the ports holed
ex and in

And while we were there he flowed the CWR Autokhana Sunny A12 head. It returned a peak flow of 27 hp - apparently some of the valves have fallen off...

Andrew, Teretonga and I were over at John Taylors, and he's claimimng 200hp at the fly for that A15/inj setup....normally aspirated!!
It also uses roller rockers, but I dont think he had a roller cam in it.

The yella terra rockers give a 1.65 lift ratio vs 1.44 stock. Damn fine items.

Nismo rockers have a 1.5 : 1 ratio. Stock A rockers have a ratio of 1.44 : 1.
As dimlight said, the A lifter blocks are too small for a roller setup to be effective easily.

The amount of lift available with the A series valve stem length/spring combination before coil bind (typically 0.480" for most double spring sets) is also a major performance limiting factor. This is why the A needs a long duration camshaft.

Hate to rain on the parade, but I don't see how roller lifters could be made for the A-series. The lifters are very small, unlike a V8's lifters. Also, there would need to be some provision to keep them from rotating so the roller is oriented correctly.
Hey, I just had a thoght. If they could make a ball-end lifter of some sort, it might not need to be as big and wouldn't care how it was oriented to the cam.
(edit)
No, just thought about it and the surface that rides on the cam has to be pretty big or it won't ride up on an agressive lift cam.

Roller rockers are for reducing friction and wear, important in a race engine for sure. But non-roller rocker arms can have a higher ratio as well (which does increase lift and duration).

Roller lifters on the other hand enable a different cam profile that can open faster than is possible with a flat tappet. They reduce friction as well.

The ford factory roller V8s have a different machined block ... but camshaft companies sell roller lifters for every kind of V8.

My engine has roller rockers and the ratio is more than standard rockers which gives it more cam lift & duration i think.