Yep, thats the way, makes the power with less duration and/or lift. The reduced cam timings can increase valve spring reliability and reduces power losses from operation of the valve train.

Torque cannot be measured in the same way. Torque depends on compression ration, camshaft and ignition timing, ring drag and crank stroke. The torque curve is still the best relative indicator of performance.

Cool, I've always been told to concentrate on torque - get that right and the hp/performance comes with it.

Most people here comment on how torquie my motor is - my A12 developments simular torque to medium to good A15's.
(91ft/lbs at rear wheels)

I spoke to Jeff at JTS today....seems I'm mostly on the right track.
Now I just need to order a cam and someone to flycut the pistons and were gunna fire the mother up.

I have a couple of turbos and a supercharger (thanks lobster) incase I need to force some air in.......but that will be a later project.....or spare engine maybe.

My old race A14 that JTS built had a very tall inlet port the top of head had been welded under rocker cover where the gasket seals it made over 150hp at 7500rpm with a 54/86 camshaft twin 45mm webbers and electronic dizzy. I have on good authority the A15 in johns 1200 is making over 180hp at 8800 quad 50mm throtle bodies roller rockers ratio??/cam spec??? All i do know is it bloody flies and sounds soo sweet
Andrew

Andrew,
The 320 degree camshaft sounds interesting, what lift does it have and what springs were you using on the head.

I am looking at making the A13 head a bit more manageable for use below the original very high engine speeds as you cannot legally run the 115/145 octane fuel the head was designed for these days. We are looking at a little decompress and replacement of the titanium valves with new 214N in the interests of a bit more durability. Titanium valves neck down and stretch with time. I want to run about 11.8 - 12:1 comp with a a smaller duration cam and a bit more lift.

As with dattomans head the head still flows like a trooper at .550 lift. This means a better lift cam and a bit more development with better springs and modded guides $$$$$ $$$$$$$ $$$$$ again.

Considering the works heads only run 0.460" lift with 328 degres duration I want to test the performance of a lower duration torqier cam with more lift.

Im not 100% sure but 0.490" rings a bell. Jeff At JTS uses them in most his A series engines had another two different ones aswell one had lots more lift could not run valve stem seals.
For a race cam it was still fairly grunty had a really rough spot at 2500 maybe carbs but pulled like a train from 5000-7500
Andrew

Jeff suggested I get a Wade grind ?08A I can't remember the first digit.
320 thou lift at the cam........which for mine with 1.65:1 rollers is 528 so I can get the head to breathe some more.
I need to find an old cam to sent to Clive now.

Now I just need someone local to machine the valve pockets into the pistons. Anyone know anyone in Perth trustworthy enough to do this without making a total cockup of it ??

Anyone make a roller cam for the A-series? Or has anyone adapted roller lifters? These would allow much more agressive cam profile (open the valve lots faster = more power).

This is one the "high tech" features new engines have, although racers have been using them since at least the 1950s. The 1985 Ford Mustang 5.0 was the first modern American production car to use a roller cam.

Maybe pitroad makes them?

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