Doc Frohmader wrote an article about porting Y-Block heads, and it's online at Egge's website HERE



Towards the end of the article he talks about port matching the intake side to the intake gasket- not much work was needed there. But he also references the exhaust side, and talks about that corner that is blocked off. It's visible in this picture HERE



Doc says not to take that corner out as it's a low flow area, and removing it will drop exhaust velocity. But, I recently watched a YouTube video where Tim removes that corner to match the entire port to the exhaust gasket. That video is HERE



At 3:06 mins into the video you can see that he has nicely matched the ports to the gasket, and has removed a large bit of metal that makes up that corner.



Any ideas as to what I should do? Right now, I've only matched the port to the gaskets on the outside edges of the port, and have completely left that blocked off corner alone.




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

55 Effie

Im no expert but I would say better to leave it as taking too much out will lower velocity. taking more out might be ok for forced induction applications... rememeber you can't go back once its gone, just tidy up around the edges.



"Came too close to dying to stop living now!"

Good stuff in Docs article, I think Johns expertise speaks for itself and it shows in his new heads.

55 Vicky & customline

58 Rack Dump, 55 F350 yard truck, 57 F100

59 & 61 P 400's, 58 F100 custom cab, 69 F100, 79 F150, 82 F600 ramp truck, 90 mustang conv 7 up, 94 Mustang, Should I continue?

I keep wondering about the loss of velocity if I did remove them. I just need to trust what people have found out through flow benches. Thanks duders

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

55 Effie

Yes I  have removed the corner area to match the gasket, but I leave the hump in and just clean up the pocket.  I don't have a flow bench but I do have a great low end in my '58, the "Brick" and "Elwood" are mostly top end but pull pretty good on the low. I also try to make the header/manifold slightly bigger than the exhaust port, 'sposed to discourage back flow.  I'm sure Ted and John will chime in soon.

   God Bless.   Tim                           http://yblockguy.com/

350ci Y-Block FED "Elwood", 301ci Y-Block Unibody LSR "Jake", 312ci Y-Block '58 F-100, 338ci Y-Block powered Model A Tudor

tim@yblockguy.com  Visalia, California    Just west of the Sequoias

Thanks Tim! So you just relieve from the manifold surface back to the hump. In essence it's like a radius from the peak of the hump in the center of the port that meets the edge of the exhaust manifold. Thanks again!

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

55 Effie

This is also a side question for you Tim (or anyone for that matter). But I've heard conflicting reports on exhaust size and velocity theories. What exhaust primary would you recommend for a 1.6 valve exhaust?



I was planning on a 1 5/8 exhaust primary, but an engine builder that I respect said stay with the 1 1/2 to maintain velocity. What do y'all recommend? Obviously I'll follow your advice Tim, and enlarge the manifold flange to cancel reverb into the ports etc. But, give me some advice cause I'm still a newb!

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

55 Effie

I think you'd want at least 1 5/8 primaries. Hold out for a little while longer and we'll know lot more about it. A very comprehensive exhaust dyno test will be taking place some time soon.


Lawrenceville, GA

I am running 1 5/8" primaries on the FED but only 1 1/2" on the '58 Effie and the "Brick", I have a kit for a set of tuned headers with 1 5/8" but just haven't assembled them yet.  As Charlie Mc said there should be some good info on headers coming up soon.  I am always learning too.

   God Bless.   Tim                           http://yblockguy.com/

350ci Y-Block FED "Elwood", 301ci Y-Block Unibody LSR "Jake", 312ci Y-Block '58 F-100, 338ci Y-Block powered Model A Tudor

tim@yblockguy.com  Visalia, California    Just west of the Sequoias

Thanks Charlie and Tim! The nice thing is I'm still probably about 3 weeks out form building my exhaust headers. So, hopefully the dyno testing will be done by then!

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

55 Effie