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Paul Workman · 07-22-2009

There is some hp to be had, based on your pix. These are some "work in progress" shots I took last spring. I patterned them after Pete's and Mark H's work. (I guess it would be considered "modern" with regard to the porting for a 350 ci engine - lots of input from Pete n Marc n Ryan n Locobob n Lee)

Pete's ports are BIG, and Marc H said I really couldn't go too big, especially on the plenum. Tho I used a 36mm ball gauge to guide the burr, after drum sanding and then flapping, the snap gauge showed I was between 36.5 and 37mm throughout

. Or, to put it another way, I had to trim the gaskets with a razor blade...

I extended the porting into the heads by coning the port to the base of the valve guides; almost 3". This shot is a primary(?) port, and the ball is a 36mm.

This is a primary port "in progress"...

And this is a secondary port after it too was coned to the valve guide and sanded.

From what I understand, most just port match the heads on a top end P&P. But, the transition is very abrupt that way! So, I did the math and came up with a bit over 2.75" "minimum" for a 33 to 36mm transition - which just fit the length of the head's runner up to the valve guide. So...It should be interesting to see what it makes on the dyno.

P.

07-22-2009	#17
Paul Workman Join Date: Nov 2007 Location: Squires (near Ava MO in the Mark Twain N'tl Forest) - Missouri Posts: 6,466	Some pix of a "36" (37) in progress There is some hp to be had, based on your pix. These are some "work in progress" shots I took last spring. I patterned them after Pete's and Mark H's work. (I guess it would be considered "modern" with regard to the porting for a 350 ci engine - lots of input from Pete n Marc n Ryan n Locobob n Lee) Pete's ports are BIG, and Marc H said I really couldn't go too big, especially on the plenum. Tho I used a 36mm ball gauge to guide the burr, after drum sanding and then flapping, the snap gauge showed I was between 36.5 and 37mm throughout. Or, to put it another way, I had to trim the gaskets with a razor blade... I extended the porting into the heads by coning the port to the base of the valve guides; almost 3". This shot is a primary(?) port, and the ball is a 36mm. This is a primary port "in progress"... And this is a secondary port after it too was coned to the valve guide and sanded. From what I understand, most just port match the heads on a top end P&P. But, the transition is very abrupt that way! So, I did the math and came up with a bit over 2.75" "minimum" for a 33 to 36mm transition - which just fit the length of the head's runner up to the valve guide. So...It should be interesting to see what it makes on the dyno. P.