I'd really like to see some substantial proof that it works before I chopped the block. I can actually see a couple reasons why it would detract from the hp numbers. Lower compression and driving mixture away from the plug during compression. I'm thinking that if there was a benefit, Ford would have done it on the F codes.

No shortcuts. There is a benefit to porting a supercharged engine. If you can attain the same flow with less blower pressure, you can reduce that pressure and achieve the same power or more. There's less parasitic drag from the blower and reduced intake temperature. Obviously you want to help the exhaust side as much as possible, because you have really helped the intake with the blower. 

Frank/Rebop

Bristol, In ( by Elkhart) 

I've also talked to Gord and he has sent me a lot of info as well. I believe that like John M and Ted, Gord does a number of things because of his experience.

Quote from Gord on the subject:"The valves are shrouded by the deck surface in a Y-block because the combustion chambers hang over the sides of the block.  This restricts the air flow into the cylinders".

Does it lower CR? Maybe, but then you can run more boost. Does it mess with turbulence? Don't know, but great quanities of air are being forced in by a blower or turbo.

Joe Abbin of Roadrunner Engineering (blown flatheads for the street) has done extensive dyno work and has imperical data to show that in flatheads, the slight loss of power due to lower cr is more than made up for by improved airflow and the increase in power it provides. Yes, I know, that's a flathead, not a y block. 

Don't know if it works, don't know that it doesn't.  But how many with high performance Y blocks are doing the little bit of block relieving that Ted showed us.

Just sayin'................

Missouri Mike

I'd rather be lucky than good.................

    but good ain't bad!!

Frank;

I guess the only way to really proove there are gains or not in a measurable way would be to build to identical motors, one with the block reliefs and one without. I spoke to an engine builder down on Long Island (a friend of a friend) who said he did  very similar reliefs on 351 blocks. I'm just sayin'

  Ron Lane,  Meridian, ID

Oh yeah!!

Forgot to add one thing.

I don't have the nerve or a steady enough hand to for something like this!!!!!!!!!!

Just stirring the pot.

Missouri Mike

I'd rather be lucky than good.................

    but good ain't bad!!

Mike: you can't equate the Ford flat head situation with a Y-Blk. It's a different setup totally. And Ted did the small reliefs on the illistrated engine for valve clearance... A buddy of mine years ago did the reliefs on his Y-Blk gasser. As far as we could tell, it made little difference. Probably offset any gains by loss of compression.

Paul

If this article about Karol Miller is accurate, it is one of many things he did to get that 150.097mph record.



"Carefully, the top of each cylinder bore was chamfered from the chamber outline to a point just above the top of ring travel."



http://yblock.blogspot.com/2007/07/ford-success-stories-karol-miller.html





Lawrenceville, GA

Charlie;

What a great article! Thanks for posting it. I'm still flip-flopping on whether or not to relieve the block, basically because I am using the lower compression 471 heads to start with. So, even though I could possibly be generating 9 psi boost with the modified VS57,could I be loosing power by lowering the compression even more by relieving the block? If just a minimal HP gain, I don't know if it's worth the risk and the work.

Rono

  Ron Lane,  Meridian, ID

I think that everything else being equal, yes you will loose power. You'll notice in that article that domed pistons were also used to account for the increased combustion chamber volume. But I'm no expert and it does not seem that anyone really knows. The increased flow potential could out way a decrease in compression... or it may not. Karol could have had that wrong, at the expense of a mph or 2.


Lawrenceville, GA

I believe that the overhanging shrouded area was considered by Ford to be a "quench area." Because the design of the Y-Blk heads is somewhat different than many other engines, there's ample indication that they were misunderstood by many engine builders. How many times have we read that "you can't do much with these heads." People like our moderater, Ted & in particular, John Mummert, have proven those statements to be wrong.. Anyway, Rono, you already have low compression 471 heads, that much removal of material will likely lower compression significantly. As I said earlier, my buddy did that to his Y-Blk Drag engine years ago, and as far as we could tell there was little if any benefit...

Paul

I did it to my block and haven't thought twice about it since. You won't ruin your block if you're patient, and slow. Make a mark as to where your top ring land will be, stay above that, and carefully radius the edge to allow for a better flow into the cylinder on your intake stroke. I'm already beyond what most people consider acceptable compression on iron heads- but the loss of one totwo cc's didn't bother me. I ended up at 10.1:1 compression. Here are the pics of my block, and my cylinder heads. And I develop fairly decent power with my motor.







The only pics I could quickly find were when I was measuring piston to valve clearance. But you can see the reliefs.

Heber City, UT (15 mins outside of Park City- basically it's in the mountains)

55 Effie