Question, can 292 heads be modified for larger valves?  I have been looking into buying the larger intake valve heads, but instead of paying $300 for heads you have to rebuild anyway, can't you just have the 292 heads ground to accept larger valves?  Not trying to build a race engine just wake up the motor some.

Which heads do you have now? If I recall correctly, some of the small intake heads have more limited size potential than others. Also, if "waking up" means more high rpm power/flow, the shrouding problem dictates that larger valves may not flow better without giving up C/R.

6 VOLTS/POS. GRD. NW INDIANA

I don't believe that 'shrouding' is an issue on a y-block. The vast majority of the flow would need to be on the side of the valve that's in the middle of the cylinder. The shrouding would be on the side of the cylinder that's right against the cylinder wall. The shrouding might, in fact, be deliberately designed into the valve/combustion chamber design. I know that Ford applied for a patent on the idea.



One possible advantage of larger valves is better low-lift flow; flow that starts earlier in the valve lift cycle. Since the y-block port design maxes out when the valve lift is at about .375", improving low lift flow improves total flow.

Best regards,



Paul Menten

Meridian, Idaho

I was thinking of John Mummert's YBM articles on Y-block head work. He provides no specific #s (though he DOES have a flow bench), but states that the least shrouded -471 head (same port/valve size) flows "considerably better" than the ECZ-G, which should have the chamber relieved around the intake valve to acheive good flow.

6 VOLTS/POS. GRD. NW INDIANA

The heads I have on my 292 are ECL-B.  In looking at the information I have they seem to be the little higher compression heads used on the 55 Tbird.

According to the YBM articles I mentioned (oops! Specific flow #s WERE included), ECL heads WILL accept large valves. They have small ports though, so even if the chambers were relieved (to ease shrouding), they would still be more restrictive at higher RPM/lift than later large-port heads (theoretically).

6 VOLTS/POS. GRD. NW INDIANA

Mummert has larger valves (around 1.80 I think) for the later small valve heads such as the COAE, give him a call and ask for his advice. Nice guy and has always been willing to answer my questions.

Glen Henderson



Freedom is not Free

Letohatchee, AL

I get the impression, way too much influence from Popular Hot Rod and Car Craft and not enough from the real world. Decide what is a realistic RPM for your engine to operate in given the transmission, rear axle ratio and that the rod bolts are 50 years old. Unless you change your cam your losing power at over 4800 RPM so what is the point. RAISE the compression, free up the exhaust, fine tune the ignition advance (57 and up) add a vacume secondary 4BBL on 57 up manifold. STOP. YOU are done. If you feel the need for more then install larger EXHAUST VALVES.

Pete,

         I'm personally found of blowers, then you're done!

Frank/Rebop

Bristol, In ( by Elkhart) 

Appreciate the feedback.  I have seen reference several times to focusing on the exhaust valves more than the intake valves to get it to breath better.  I assume the higher ratio rockers would be a cheap addition that would help breathing also.  Thinking about the FPA headers.  Have used them on my mustangs with great success.  They are pretty expensive but are a quality product.  Going to go after the brakes also, going is one thing not stopping is a whole 'nother rodeo.

Just a 50 year old with money whose dad never let him have a cool car, now I can do what I want because my wife if cool and understands I will never completly grow up.