I use a roto zip tool for porting. Powerful durable and inexpensive. They come with a 1/4 inch chuck collet. I quit using an air grinder as running a 5 hp compressor for hours to power a 1/4hp air grinder seems stupid to me. I use a round stone in the bowls and a cutter with a long sank in the ports. I use a loose valve guide to stabilize the long shaft when porting as I cn hold it safely with my free hand.
don

_________________
8 cylinders are for folks who cant make HP

Ok, here's a stock port (with the seats started to be blended) and my progress so far. I'm going to port as if it were stock valve sizes, then when done enlarge the seats for bigger valves. The second photo is the port work in progress. I cut OUT perpendicular to the valve stem on the port floor valve seat edge (part of hole next to intake side) - I did NOT undercut the floor. The third is a closer look at the same picture in #2. I played with the contrast.

_________________
Tom
'86 Alfa Romeo Spider, red "Dinsdale"
'10 Corvette, red "" (no name yet)
'95 Ferrari 348, red "Zoom"
'04 Maserati, black "Evil"
'05 Aston Martin DB9, green "Bond, Treasury bond."
'82 Dodge W150 Power Ram, yellow "E. Valdez"

Oh, I have to start the Dremel by hand but it works, just a little less power. have a 1/4" collet flexible shaft grinder coming in from the bay of ease.

_________________
Tom
'86 Alfa Romeo Spider, red "Dinsdale"
'10 Corvette, red "" (no name yet)
'95 Ferrari 348, red "Zoom"
'04 Maserati, black "Evil"
'05 Aston Martin DB9, green "Bond, Treasury bond."
'82 Dodge W150 Power Ram, yellow "E. Valdez"

Not bad. You have the right idea.
don

_________________
8 cylinders are for folks who cant make HP

Thanks! Still waiting on the bigger grinder so I can make more metal dust.

_________________
Tom
'86 Alfa Romeo Spider, red "Dinsdale"
'10 Corvette, red "" (no name yet)
'95 Ferrari 348, red "Zoom"
'04 Maserati, black "Evil"
'05 Aston Martin DB9, green "Bond, Treasury bond."
'82 Dodge W150 Power Ram, yellow "E. Valdez"

Dh-oooh! Checked to see the status of the die grinder - turns out it is still in my "watch" list.

_________________
Tom
'86 Alfa Romeo Spider, red "Dinsdale"
'10 Corvette, red "" (no name yet)
'95 Ferrari 348, red "Zoom"
'04 Maserati, black "Evil"
'05 Aston Martin DB9, green "Bond, Treasury bond."
'82 Dodge W150 Power Ram, yellow "E. Valdez"

Just be real careful as you port up into the valve guide area of the roof. The port is really thin on the 'low side' of the guide. That's where I went through to water. I cut the guide down as much as I dared on head #2 but didn't eliminate it completely.

I relayed the info about using the .200 deep seats for the exhaust and my machine shop was able to do it no problem. But has to be done before porting.

There is also a thin spot where the port wall goes flat - don't try to blend out that flat to match the rest of the port, or you'll go through.

It's also funny the head I am using now came from Albequerque, I was driving through on my way to Boulder and I called a craigslist ad and picked it up.

I'm not going to do much with the ports themselves. Most of the work will be in the valve seat area and some smoothing of the guide area. Need to get guide inserts installed before I can blend the guide boss and cut the oversized seats. Wish I could find a gauge to measure the valve guide ID for cheap - it would be ideal if the guides didn't need to be replaced. I don't understand the last bit about the flat part of the port. Intake, exhaust or both? Side, floor or roof? Thanks for all the info!

_________________
Tom
'86 Alfa Romeo Spider, red "Dinsdale"
'10 Corvette, red "" (no name yet)
'95 Ferrari 348, red "Zoom"
'04 Maserati, black "Evil"
'05 Aston Martin DB9, green "Bond, Treasury bond."
'82 Dodge W150 Power Ram, yellow "E. Valdez"

In the Chrysler shop manuals of the 1960s there was a method to check by pulling the valve out a certain distance and checking the wiggle with a dial indicator. I worked in the head shop of a big machine shop for several years during my apprenticeship and we use to put our finger over the end of the guide and pull the valve smartly out. A good guide will give a distinct "pop" A worn one wont. We would mark the bad ones if any where found and then measure them although I wonder what for because they had to be replaced. Crude and simplistic as it sounds it was a fool proof method. A worn guide will not pop plain and simple. We made our bonus on our productivity and mistake is any were deducted which could kill any dreams of the bonus. It is a good method . Make sure valve is good and there is no burr at the top. Do it dry..
don

_________________
8 cylinders are for folks who cant make HP

I have a dial indicator and magnetic mount. Will drop in the new valves and raise it up oh like 0.375" or 0.4" and do the slop test. However, even after searching the internet there does not seem to be a figure given by a reputable source. Will look for an old industrial slant six manual I have and see if it gives a figure. If memory serves - there's a fair bit more tolerance than most people would imagine.

_________________
Tom
'86 Alfa Romeo Spider, red "Dinsdale"
'10 Corvette, red "" (no name yet)
'95 Ferrari 348, red "Zoom"
'04 Maserati, black "Evil"
'05 Aston Martin DB9, green "Bond, Treasury bond."
'82 Dodge W150 Power Ram, yellow "E. Valdez"

The new clearance is between .0015"-.003", trying to use the slop method introduces a lot of deception into the mix because the valve becomes a lever, and multiplies the perceived clearance by a ratio of the amount the valve is sticking out. The machine shop should be able to give you an idea what clearance they put on the stems once they replace the guides and hone them.

_________________
There's no such thing as too much cam....only not enough engine!

It was in the shop manuals as late as 1969.
However an .003 guide will NOT pop and a .0015 will pop smartly.
don

_________________
8 cylinders are for folks who cant make HP

Took the rest of the valves out as I got the "C" clamp style valve removal tool in the mail. I cleaned the valve retainer area of the valve stem then pulled out the valves. Some took a really sharp tug to remove, others rattled on the way out

_________________
Tom
'86 Alfa Romeo Spider, red "Dinsdale"
'10 Corvette, red "" (no name yet)
'95 Ferrari 348, red "Zoom"
'04 Maserati, black "Evil"
'05 Aston Martin DB9, green "Bond, Treasury bond."
'82 Dodge W150 Power Ram, yellow "E. Valdez"

Finished cleaning/porting the bowl and valve seat area. Going to stick with the stock exhaust valve size and go with larger intake valves. Want torque. Next stop: machine shop. Valve guides and cut for the oversize enginebuilder intake valves. Hadn't planned on doing anything with the ports till I flipped the head on its side and braced it. Ran a rotary wire bursh in it to clean it - had only cleaned the bowl area before starting the porting. Peered in to the ports from the intake/exhaust and zowie - what a mess. Casting bubbles and a close to 1/4" blob of schmegma sticking out in to #6 cylinder exhaust port from one of the walls - a huge casting irregularity about 1/4" wide, 1/8" thick and 1/4" deep right out from the side of one of the walls. Plus some casting ridges on the walls and some messy gobs on the floors of all the ports. Got a big honkin pointed stone about 3/4" in diameter and hooked it up to an electric drill and ground off all the mess. Need to get a flapper wheel to try and smooth out some of the exhaust port, will go with a finer stone on the dremel to smooth out the intake port. The shape of the port as it approaches the seat is an issue - as the seat area actually protrudes into the port cross section - on the forward and aft sides of the valve seat. Going to oversize valves will help reduce this nasty lip - I bet the removal of the lip area will actually help airflow more than the actual increase in valve size. Well, that's the status so far. I wanted to open up the valve seat port area to the existing seat diameter before having the seats enlarged.

_________________
Tom
'86 Alfa Romeo Spider, red "Dinsdale"
'10 Corvette, red "" (no name yet)
'95 Ferrari 348, red "Zoom"
'04 Maserati, black "Evil"
'05 Aston Martin DB9, green "Bond, Treasury bond."
'82 Dodge W150 Power Ram, yellow "E. Valdez"

Don, are you eliminating the guide boss on the exhaust side as well...?
Im doing my head now and the transition from bowl to port would be much improved in my opinion if it were gone..and blended into the roof..just wondering if there is enough meat there..the cutaway pics on image searches seems to prove that there is.