I know this topic has come up about 500,000 times, but I have a couple more questions.

Due to recent events, I am in need of a new pair of heads. I do not plan on keeping the 305. In fact, I can difinitively say that the first thing I will do when I graduate is pull the 305 to make room for a 350 shortblock. I do NOT want to buy a set of performance heads twice, so I am planning on picking up a set of heads with the 2.02 intake and 1.60 exhaust valves.

I have read posts stating that valve shrouding will not be an issue until approx. .520" lift. My cam is only .471 intake and .480 exhaust. That takes care of issue one.

The issue that concerns me is the physical constraints of the motor itself. From what I am reading, it seems like the valve to bore interference varies from head to head, depending on it's placement.

Since I'm kind of walking off the beaten path, are there any known heads that will not work with the 305? The only one I know for sure on so far is the edelbrocks, but I really wasn't considering them anyways

I am interested in the trickflow 23deg, dart iron eagle 180cc, and the pro topline lightning 180cc. They are all 64cc, and will be milled to 58cc. I also want to stick with cast iron, because to take advantage of the higher compression ratio that I can run with the aluminum, I'd have to shave the heads to 50cc's to bump it to 10.6:1. Might as well leave them at a usable range for the 350, and just leave the compression where it is now.

If any of these heads are known to work or not work with the 305, please post.

If you have any good info on the heads I listed, or have any other good heads to check out that are approx 180cc runner and 58-64cc chamber, please post.

I am already aware that I might be loosing a little potential power by going with the oversized valve on the 305. This is a known threat, and if this is the only contribution you have to make, please do not post

Thanks for the info ahead of time guys, and sorry if I seem alittle "off" still. Got both heads ported, was working on port matching my third to last exhaust port and cut through to the coolant passage. 12 hours and $100 down the drain. Live and learn I guess, at least it happened now instead of me leaving the wall paper thin without realizing it and having it burst while I'm driving. Then I'd be looking for a complete engine

 

Here is one answer to shrouding on 416's...Deshroud!

 

Since you've acknowledged the potential for flow loss and are willing to live with that, the major concern should be preventing damage to your new heads and valves.

If you calculate the diameters of the valve faces and teh required space between the valves, you'll discover that the arrangement of 2.02/1.60" valves in a 3.736" bore is tight, very tight, indeed.

You will need to be very careful in your installation and measurement for clearances so you don't open a valve into the deck. Theoretically, it will all fit, but just barely. Given production tolerances and variations, you'll need to verify clearance before even turning the engine over. Valve checking springs might be a very good investment.

So, you struck water in your mining efforts, eh? Any chance of having the '416 heads welded? Know anyone that's good with a TIG and nickel filler material?

 

You can repair your bo bo on the exhaust port with this

FIRE SEAL 2000
or simular hi temp ceramic steel repair materials..
Like PYRO PUTTY

You don't need to make the exhaust ports huge or the same shape as your headers opening.
No need to remove that much material in the exhaust port.

I repaired my exhaust port sucessfully with this stuff.
Let it dry and cure for a week before using it.
It actually gets harder and fully cures with heat (exhaust).

 

or...

 

Yep, unfortunately I now have a hole about 1/4" square right before the bowl on the side of the port. Any idea what a shop would charge to weld up my mishap? What's the valve checker spring that you talk about? Is that just a lower tension spring that would allow me to push down on the valve?

F-Bird88- That repair compound stands up to the coolant constantly on it's back? That sounds like a great alternative, plus it's only $10

Thanks so much for the replies fellas, have a happy easter!

BTW, those valves look huge in there riley

 

Have you tried this permatex stuff? I could grab that at the autoparts place, the other stuff I'd have to order

 

The stuff I actually used was "Hi-temp Steel Repair"

but same thing. Worked very well.

On one of my ported 305 heads:

I tried to drill out a broken exhaust manifold bolt in the head after breaking off a easy out remover in the broken bolt. had to drill around the bolt with a 1/8" drill bit till I could pick out the broken bolt and drill and install a heli coil. Well I ended up drilling right into the water jacket
and poked a hole into the exhaust port too.

stuffed this ceramic/steel repair material into the hole and then made a shorter header bolt so the bolt would not bottom out on the material in the hole. Installed the heli coil and it worked geat. this stuff dries hard as a rock and loves heat. Stood up to the pressure of the cooling system and the heat of the exhaust port.

All I can say is, "it worked for me".

You do not need to go to a 2.02x1.60 valve combo to get good flow out of these heads.

A 1.94 x1.50 combo will work better for you.

I got 239cfm on one set and 232cfm on another on the intake port and 180cfm on the exhaust with these sized valves. The larger 2.02 will flow less unless you do some significant deshrouding.
Again the 2.02 is not nessessary or recommended
on this head.
Search my old posts for the hows and whys.

 

If I end up getting these heads to work, I was just going to stick with the stock size valves. Otherwise, I really can't find any good flowing aftermarket heads with the 1.94 valves and a 64cc or smaller chamber. It seems like all of them with the size chamber I need to maintain my compression is the 2.02 valves.

I'm not at home right now, so I can't post a pic of the hole. Here's an artist's rendition The metal surrounding my mistake is pretty thin as well. I'm not gonna hold anything againsed you if it doesn't work, but do you think it will hold up?

 

You said you wanted to shave the heads down to 58cc. I've tested 64cc chambers with 2.02/1.60 configurations and .520 lift is roughly where the valve shrouding would occur, I'm not sure how the 58cc would work out. I'm sure you've read some of my past posts on this topic.

 

Yep, thanks for the info Id have to shave roughly .030 off the heads to acheive that ratio.

One thing I couldn't find though, is how were you able to test how much the valve would be shrouded, and at what lift?

Any idea if there is any aftermarket 2.02 castings I can't use?

With the 305, would it be wise for me to keep the intake runner volume to 180cc or less, or can I step up to 190-195cc and still keep most of my bottom end torque with the smaller displacement engine? Are there any formulas to find out what would be optimal for me?