Does anyone have any pics of deshrouded vanguard big block heads? Im piddling with a set and was wanting to get a look at some before i take the die grinder to em. You can clearly see where the intake valve is badly shrouded.

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Thanks a bunch! That looks like a machine did it. I reckon a little bit goes a long way

Whats do you gain/purpose for deshrouding? Excuse my ignorance just curious. My heads are done the same way.

Simple answer: increases and improves air flow for a given valve lift. More air = more power.

another thing to add is that deshrouding removes material from the combustion chamber and that lowers your compression.
you need to take this into account when you deck your heads.

Not enough to worry about. Last time I talked to Jamie about it, I want to say it was only like 1-2 psi difference.

Im staying somewhat conservative and decking .040 and just smoothing out the castings. Reckon a factory gasket will be fine for the heads or should i go flat out gasket or copper even?

Stock gasket is more than sufficient.

Swampeast101, my heads are decked .050. Heads are deshrouded, larger Manley valves, port and polished. This was a heads worked by Jamie pre delta performance. I also have a BPS cam and only at 175 psi cranking compression. I wouldnt be scared to go more than .040 if your worried to be to high on compression. Cam will play a big factor in that to though.

What is the definition of deshrouding? Been studying the headwork for some time now and haven't ran across that term in all the reading and talking with people I've done .


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I went with deltas cam and over sized manley valves, i was worried about too much compression and not real sure on how to address the valve geometry issue with the heads being shaved. I did order some of the pink valve springs ahead of time for it though. Seems like theres a lot of different opinions on decking, some say .050 others say .030 so i was figuring middle of the road and go .040, if they haven't decked them yet i may go more.

Kirk, valve shrouding is basically where the edge of the combustion chamber on the head blocks good flow from when the valve is opening and hinders good swirl, folks will grind a little off the shrouded side to help flow. In turn, it does lower compression numbers slightly but the benefits are believed to out weigh the cons. Its also done on lots of cylinder heads not just limited to small engines.

I would give delta a call being you purchased the cam from them. I'd be willing to bet they can give you an estimate on cranking compression according to decking amount and get you pretty close to where you want to be.