Are these any good? BBC 396 3856206 Oval port Closed chamber heads. Any comments?

Good as any other GM head. The closed chambers will get the comp. ratio up if you're using a flat top piston. If it's on a domed piston, c/r will likely be 10.5/1 or higher. With a little unshrouding, and maybe bigger valves, they will work very nicely.

Good as any other GM head. The closed chambers will get the comp. ratio up if you're using a flat top piston. If it's on a domed piston, c/r will likely be 10.5/1 or higher. With a little unshrouding, and maybe bigger valves, they will work very nicely.

Do you know the stock valve size?

I run a set on my 13:1 compression 427.
I installed 1.88 exhaust valves, but retained the 2.06 intakes (stock valves are 2.06/1.72). I also did some intake valve unshrouding, and gasket matching. I am very happy with the heads.

I have a bare set out in the garage.

They are supposed to vary between 96.7 and 98 cc's so cc them so that you will know for sure!!

pdq67

I run a set on my 13:1 compression 427.
I installed 1.88 exhaust valves, but retained the 2.06 intakes (stock valves are 2.06/1.72). I also did some intake valve unshrouding, and gasket matching. I am very happy with the heads.

What is the biggest intake I can fit in the head? 2.19 or 2.25?

I figure 2.19" will do you nicely!!

That said, you will have to plunge-cut relieve them so they will breath right and so doing will lose you a bunch of cc's, so then you will probably need to plane them some to get back compression if you want to!!

I mention this b/c a flat-topped pistoned P/U motor 454 will be about 9.2 to 1 CR., w/ stock -206's, up from like 7.9 w/ -781's!!

If I was to play w/ bigger valves, I would rework my cast-iron Merlin ovals and install 2.25"/1.94" valves for my 496.

pdq67

and so doing will lose you a bunch of cc's

Dont you mean 'gain' a buch of cc's?? Which you will then have to lose again by milling the heads.

And also, not necessarily so. When I had my 215's done over with bigger valves, even with the unshrouding, they only measured a couple cc's larger than before. With the new larger valves, sitting in the correct spot now after the new seats, it didnt change things all that much.

I dont know that you can go to 2.25 intakes, those chambers are not too big. I went with 2.19's also. I would think that's plenty. As dadeo-3 says, even the stock valves do a nice job.

The reason I stuck with the 2.06 intake valves is because of the shrouding issue.
I installed a good flowing race-flow valve with an undercut stem to help the flow numbers, and minimized the ammount of cc gain because I did not have to plunge cut them as much.
It actually worked out very well, and the heads make more power than I expected.

Right John,

I always think in reverse is all!

Plunge-cutting them will increase the chamber's cc's and then planing them will decrease their cc's..

Sorry about that.

And I like to use the old stock type, .020" thick steel shim headgaskets to up the CR. a schosh more vs the more common .038"/.039" or whatever thicker composite headgaskets.

pdq67

They are the early narrow chamber heads. A lot of people run into water trying to put 1.88 exhaust valves in them. For a 396 that isn't turned too high they work fine but if you are really serious find a set of the 215 style.