Hey everyone,
I fired up my 69 396 on the test stand a few days ago and it looks like I am in need of some head work. I have a couple low psi cylinders and some loose valves. :eek: The low pressure cylinders just happen to be the ones with the loose valve guides. graemlins/clonk.gif

I was going to put in the 2.19"/1.88" valves when I had them redone, figure what the heck I am in there anyway. But my block is a 69 350hp. I don't have the heads off yet, but I am assuming that they are not notched for valve clearance. I am looking at about .550" lift on my cam, plus the big valves. Am I going to start hitting the cylinder bores with the valve heads? The heads are 69 290's and the block is a 69 350hp 396 from a Chevelle.

Thanks guys, some recent carnage pics on the board have me worried.

I have closed chamber heads with .555 & .558 lift with no probs, flat top kb pistons, with the notch for the one vlv. in my 454

You will NOT have any problems what so ever going to 2.19/1.88 valves in your .040 396

As always you are very helpfull guys, thank you. Looks like I am still good to go then. Shooting for 400 streetable hp with stock heads. I think with a big block I have a good shot. graemlins/beers.gif

I probably have the same heads you do on my '70 396 (402) BBC 350 hp. Went with 2.19/1.88's and love it. These have plenty of flow for the app! What are the casting numbers? I'm pushing out 450 HP to the ground with a mismatched cam. You should have no problem getting 400 out of it.

Originally posted by SS_Sean:
I'm pushing out 450 HP to the ground with a mismatched cam...you mean at the crank ;)

Like the guys above said, you should not have a problem with valves hitting the block with that lower lift cam. I can't say for certain because I've never run a big valve/big cam BB without block notches.
But if you decide to overhaul the motor, notch the block using the head gasket as a pattern. That'll help flow and allow higher lift cams if you want to use one later. Remember, a 396 +.040 has the same bore as a small block 400 +.010

Randy

The notches at the top of the bores are for air flow rather than valve clearance. Good idea in the small bore big blocks.

Originally posted by Keith Tedford:
The notches at the top of the bores are for air flow rather than valve clearance. Good idea in the small bore big blocks. Huh. Good idea. I was a bit worried about stuffing a 2.19" intake valve in that 4.135" bore. But I guess the valves not being straight like a small block makes them clear? This is my first couple big blocks so I am trying to be careful.

Originally posted by mr 4 speed:
</font><blockquote>quote:</font><hr />Originally posted by SS_Sean:
I'm pushing out 450 HP to the ground with a mismatched cam...you mean at the crank ;) </font>[/QUOTE]Oops...yup, that's what I meant. redface.gif