That is true about the duration. I overlooked the fact that the exhaust was shorter. The increase there is definitely better. Well then, it's not so bad after all.


Lawrenceville, GA

Charlie,

   Steve is right about what I meant. It does seem to me that the exhaust was too short for a blower motor. Most of the (flow) numbers I've seen would seem to indicate the heads all need help on the exhaust side, blown or unblown. I'm not at all sure why Ford used less duration on the exhaust side of the .290 cam, maybe Hoosier can help on this one. It made no sense to me. I wasn't allowed to port the heads for pure stock, so the only thing I could do is sneak a little more duration on the exhaust. The Tech guys can easily check lift in the car, duration could be done, but would be harder to do. They have no specs for these motors any way. Hoosier provided IHRA specs back when, but NHRA has none. The pure stock people would have no source for those numbers, unless we tell them. The specs call for 16 inches of vacuum @ 1200 rpm. That's it!

Ford has had a reputation for good intake ports, and not so good exhausts. Clevelands and the 385 series heads come to mind. Most of the small block stuff didn't flow on either port, but they intended to pull 4000 lb cars around with 289 or 302 inches, so low end torque was probably the object, not horsepower.

Frank/Rebop

Bristol, In ( by Elkhart) 

Charlie  - I think that what Frank is saying is that the original style blower cam needs some help on the exhaust side. It can use more exhaust than intake and the factory tooling was putting the same lobe design on both.

The intake side of the head is getting help from the "pressurizer" - but the exhaust port is the same as a four barrel. If you can't give the exhaust flow more room - give it more time.

right? 

 
 Steve Metzger       Tucson, Arizona

So the stock blower cam is a dual pattern?

What is the cam in the Y-block book? The duration @.100 for both lobes of that cam is 198.

It sounds like I don't have a very faithful reproduction. It disappoints me some. I never expect repros to be exact but this is a little more variance than I expect in a repro.


Lawrenceville, GA

Chuck/Charlie,

         I finally got the blower book out. If you look further down the page you get the nuumbers @.100" lift. Almost all cams are rated @ .050" today so the numbers are going to be at least 6 or 8 degrees longer than shown. The book gives a 226 deg intake and a 216 exhaust duration and tthe lobe lift is .290 as John stated. Remember, that's at .100 lift so the intake becomes roughly 232 or 234 @ .050, while the exhaust checks at 224 or so. I added 10 degrees to the exhaust side of my cam, and used stock lift numbers. I would simply ask Mummert to get you a cam with the F code intake, a 232 or 234 deg exhaust lobe and spread the lobe centers out to 112 degrees. You can get some offset keys and play with the cam timing once you get it running. Suggest you contact Hoosier or Mummert about valve springs, you'll need good ones. Ditto with the con rods and pistons, use a rev limiter too.  

Frank/Rebop

Bristol, In ( by Elkhart) 

I found the cam card. It does say 274 advertised with 226 @.050 and .295" lift. Maybe it's a result of measuing the duration at a different lift point to make it easier to compare with newer cams. It has .005" higher lift too. There was only one blower cam right?

I noticed that the 290* is taken at .016" lift opening and .078" (or something weird like that) closing in the chart in the Y-block book.


Lawrenceville, GA

Thanks John.

I know very little about cams. Didn't see the published lift on the other cam. Sounds like this Isky will do the job then? Chuck

Y's guys rule!
Looking for McCullouch VS57 brackets and parts. Also looking for 28 Chrysler series 72 parts. And early Hemi parts.

MoonShadow, 292 w/McCulloch, 28 Chrysler Roadster, 354 Hemi)
Manchester, New Hampshire

Chuck:

The factory blower cam had .290 lobe lift, which with the 1.54 rockers, produced .446 valve lift.  Don't know what you mean by "lot".

John

John - "The Hoosier Hurricane"

Does the 448 lift on the Isky cam I posted seem a lot? Chuck

Y's guys rule!
Looking for McCullouch VS57 brackets and parts. Also looking for 28 Chrysler series 72 parts. And early Hemi parts.

MoonShadow, 292 w/McCulloch, 28 Chrysler Roadster, 354 Hemi)
Manchester, New Hampshire

I'll dig up the spec card. I thought that is what it said. I ordered the blower cam from John Mummert about 3 years ago when the repros were available. Hopefully that is what I got.

It says 274 on his website. http://www.ford-y-block.com/perfcams.htm


Lawrenceville, GA