SO we were finally adding those 1.6 rockers... got the heads off and over to the machine shop... guess what... one of the heads is cracked! The other has a bad cut in the valve cover seat...

So all my port work has to be redone on a new set of heads....

So luckily, we had Joe's junk 2.8 from his fiero, to go to get another set of heads off of.

So since I am reporting from scratch.... Any thoughts on taking it further then a gasket match porting????

 

Was hoping someone would have some thoughts on the subject....

I was planning on opening things up a bit more since I got that larger better flowing Truleo intake now...

How far you think I should go past a gasket match???

Shark fin the hump???

What do you think this would do to the flow????

Want to take it beyond what super six has done with their stage II heads!

 

Did they crack because you ported them so far before? Or did they crack elsewhere?

I think your one of few who have ported there heads, so the rest of us are kinda in the dark.

 

Oh, I don't know about that.


Gasket match EVERYTHING. Do not go past gasket matching. Smooth the short radius dumping into the bowl. I did clean out the airflow vane area, but do NOT cut down on it. All the info I've found says that is worth 17% more airflow by itself - but that doesn't mean you can clean it a little. Nothing under 80 grit in the head's runners, though - you have to keep the fuel in suspension.

If you haven't polished the chambers, DO IT. BIG help in preventing detonation.

When I did my heads, I just decided on a quick cleanup, and nothing major - GM rates the heads @ 1.5hp/ci with mild cleanup work

 

No it was not from the porting... the crack was btw the 2 valves on one of the ends.... got pics... got to resize and post!

 

Well I had the old ones gasket match ported and feathered into the stock size. Cleaned up all the old casting flash and any sharp edges as "Standard Abrasives" recommends! Used a stone that should have been around 80 grit in the intake ports....and the chambers very polished...as were the exhaust ports...

So my old set up was as you described... Would this basically in in line with Super Sixes Stage II heads? Do they do larger valves???

But I was not happy with the flow.... esp with the new intake...

So what is the reason for NOT going further... Just cause it has never been tried, or becasue it was tried and bad things happened???

 

Ok pics of the crack in the head... if I can figure out how to do that with this new system...

 

Damn girl!!

Quit beating on her like a red-headed step child

Is that a 3 angle valve job I see?

 

Joe always jokes that I'm either full on the gas or on the brakes...

The valve job was an old one that a mechanic had done 60,000 miles ago... well he said he had a basic valve job done...

The new heads are getting a multi angle valve job! Wonder how much power loss I had to a poor valve job previously. Granted the car never smoked...

 

When I had my heads done, they said a 3angle was the lest and "part of a normal head job". So thats prob what ya got.


When you get the new heads done, I want pics of the ports and the angle valve job

 

could just cut the crack out and run siemse port valves

 

sure... hope to get them back on and get some numbers b4 to long!

 

I might be on to something here, ey?

you would need a sort of 1 way flapper valve up and down stream but both/all valves could be open on the intake n exhaust stroke.

 

Siamese port valves... lol!

So I'm trying to figure out looking at the intake side of the heads... If one was to increase the intake port slightly, would you need to run a bigger valve to compensate, or is the existing bowl and valve larger enough???

I guess the reason I have been thinking so hard on doing a port increase is this idea... so the 2.8, 3.1, & 3.4 all have the exact same heads... why I wonder is the whole 305 versus 350 arguement... Like ours they are the same family of engine... but you would never run hte heads from a 305 on a 350, even with a gasket match port and call it OK! So why would we run 2.8 heads on a 3.4????

 

Shannon, I read somewhere that the ideal size is .75 the valve size.

So intake being 1.72 the hole behind it should be 1.29
Exhaust being 1.42 should be 1.06.

 

One of the oldest tricks in the book is to stick a set of large valve 305 heads on a 350.