Jester

I need to get my head chamber volumn down quite a bit. enough that I'll prolly have to have the intake milled anyway (at least 40 thousandths). Would angle milling be better?

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ICON Motorsports

ede

i've never done it, heard it opens up a lot of new things to consider. it does reduce volumn more i believe. if you're going to cut the intake anyway i'd do it.

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1st & 3rd

md

.030” is about the max you can flat mill a head before you start getting into the intake valve seat. So angle mill looks like your only choice unless you go with a “raised crown” piston. Angle milling is pretty spendy, three to four times as much as flat. You will also have to watch the pushrod clearance with an angle mill. Different pushrods will be a must. Most likely .050" short but you wont be able to tell until the head is bolted down and you check the length. You may also need to use double thickness intake gaskets. Be careful how much you take off. Some castings are pretty thin on the outer side of the deck between the bolt holes.

Mike

JakeJr

I don't know which set of heads you're considering but here's my experience with the stock cast iron Vette heads.

The heads you're using may be different depending on the deck thickness and coolant passage locations, etc.

When I rebuilt my engine last year, I wanted to increase the compression too, so I had a local machine shop angle mill the heads.

I wanted them angled milled 0-.100; with zero taken off the intake manifold end and the removal gradually increasing to .100 on the exhaust end of the head.

Because of the way the stock heads are cast, the shop could only remove a maximum of .080 on the exhaust side for fear of milling into the area of one of the water passages.

The milling of the heads did not require any mods to the intake manifold since no metal was removed from the intake mounting surface of the heads. The stock manifold lined up perfectly using Fel Pro intake manifold gaskets.

In addition, I did not need to go with a different length pushrod. I bought new ones, but they were stock length.

I DID, HOWEVER, have to have the press in studs pulled and the stud bosses milled down and tapped for screw in studs and guide plates. Without the screw-in studs guide plates, I bent a bunch of the stock pushrods; which is why I ended up buying a new set.

After the screw-in/plates were installed, I never had any more valve train trouble. BTW, I was running a ZZ9 with 1.6 RRs.

Generally, flat milling the head more than .030 will require the intake manifold be shaved too for proper port and bolt hole alignment; which is the best way to handle the mismatch that results.

Removing most of the meat from the exhaust side of the head did not require any mods to the stock exhaust either. Stock headers bolted right up without a problem.

Spent a lot of money on mods to the stock heads only to pull them a few months later and install a set of aluminum Edelbrocks. Oh, well.

Hope this helps,

Jake