I've built a couple of other Y-Blocks, but never have tried this before so I'm a bit nervous. Anyway, before I put the carbide to the iron I would like your advice and even "is this trip even necessary"?

This is my 331 cu.in. blower motor project using a modified VS57 supercharger with a high output impeller that John Erb says should produce 7-9 psi boost. I got some pictures and info on how to do it and I'm posting a couple of pictures here of what I'm planning;

Using new Fel-Pro Permatorque head gaskets I set scribe lines in blue dye. The cylinder ring ridge is about 0.300" from the deck so using an old (borrowed) piston I set it in the hole about 1/2 way to the ring ridge(0.150") as a guide. The black duct tape on the piston is so I won't gouge it by accident. USing a carbide burr I'll SLOWLY cut out these areas being careful to stay inside the scribe line. I'll buff the cut outs with tapered rolls and cross buffs so carbon doesn't build up. That's basically the plan. I'll be using ported 471 heads and also planning on drilling a new road draft tube hole in the block where they were on the 56-57 motors to relieve crankcase pressure.

So, what are your thoughts? Is this step really necessary. I'm not proud, I'll stop right now if the benefit is minimal.

 Rono

Rono (11/19/2011)

---

Okay, Gord McMillen has been providing me the info and pictures. He has built and raced quite a few supercharged Y-blocks and is manufacturing the blower kits for y-block set-ups. His rationale for the block relieving is so the motor can breathe better under boost considering the typical valve shrouding of the Y-Block heads. Maybe the 471 heads I'm using pose less of a problem than the "G" heads or Mummerts new aluminum heads, I'm not sure, but if you guys think I can skip taking the risk on doing this (one bad slip and the block is toast), I'll be happy to pass on it. below is one of the pictures that Gord sent me.Rono

I have done this block relieving on y blocks for years and see no problems if you go carefully. Many of us have little pecularities/features that we like to do when building engines, After being on here for a fair while it sure is obvious that a majority of relative newcomers seem to want to reinvent the wheel or y block. Go with your idea carefully and doubt you could toast your block. Just my opinion. regards bill.

Im new to the forum, but this is my 2 cents.  If you understand the risks and you can afford to possibly ruin this block, then i say go for it.  Remember that buy doing this you will be lowering the compression ratio.

Hope this link helps

http://www.streetrodderweb.com/tech/0905sr_ford_flathead_myths/index.html

Here are some pictures of what I do.  This simply gives a bit of room around the intake valve when it’s fully depressed.  When using higher than normal lifts at the valve, this notch becomes mandatory in that it keeps the intake valve off the edge of the cylinder.  When notching the cylinders, make sure the notch does not get into the top ring area of the cylinder.

Rono

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. 

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 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'

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

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

I did it on my engine based on the Carroll Miller article.  However, I think that Ted has right idea and that the only thing necessary is notching for the intake valve with a big cam and small bore.  The gains are probably not much if anything especially with a blown engine.

BTW what are those radial slots in the pistons of Ted's engine?

It is my opinion that of the many variables in the success of that engine, the quench area and these reliefs played a major role in developing approximately 310 hp.

You, me and Y Block Billy will need to hook up next summer. We are all within a couple of hundred miles of eachother. I'd like to check out your McCulloch set-up too.

Rono

The straight slots are there to help direct the compressed air/fuel mixture towards the spark plugs from the quench area.  These are typically used as a detonation deterrent.

Rono