besides the obvious increase in compression,is there any real benefits to angle milling a set of 23 deg. heads?i know the intake will have to milled also to compensate,but my buddies uncle owns a machine shop and will do it all for $150.....just wondering if there is any "BIG" flow #s to be had with angle milling?(heads would be taken down to 53cc)

You'll not see huge gains, but it does help to flatten out the valve angle as well as tip the intake port a bit. If you can get it done that inexpensively and they correct all bolt holes, etc. and you can use smaller chambers, I'd say do it.

Angle milling besides reducing combustion chamber volume, reduced the valve angle relative to the block (poor man's 18° head). this gives a straighter shot at the valve from the intake side (which also means misalignment problems with the std. 23° intake so you have to machine a mating surface).

This reduced valve angle with improved breathing is the answer to a question I had always asked myself during early evening get together with fellow car enthusiasts on deserted roads; namely how can a Chrysler 340 Duster not only keep up, but often beat a 350 Chevy Nova. The answer turns out they do not run 23° factory valve angle heads, but a lesser angle of 18° and run rocker shaft rockers too (SBF have a 20° factory valve angle also with shaft mounted rockers). You have to go to GMPP or aftermarket to get a SBC 18°, or 15° head.


Larger Dave

If you really want to see an awesome cylinder head take a peek at the Dart Little Chief! How does 400+ cfm on the intake side sound? You can build a pretty stout big inch small block with those flow numbers!!!

If you can get it done for 150 for everything, by all means do it. Ive angle milled many heads and its a TON of work to get everything correct(spot face the pads, re-angle the intake flange, re-align the head bolt holes.....)The gains are usually noticable, though I wouldnt recommend it for just a street motor, not seeking to get every last ounce. And every head design is different as to how much flatter you can get the angle.

Randy

Randy said what was on my mind,,, Respotting the head bolt surfaces,,, expecially the outer. I think you have also move the valves closer to the piston on the fly cuts? Hope you were not on the ragged edge. I cut my BBC .100 on the exhaust side and 0 on the intake manifold side and could see some differance.

use to angle mill our 461 heads for super stock dirt car ,saw real gains,next step was dart 2 heads, better flow, 150 bucks ,angle mill!!!