clearwater big valve head

[boatmechanic1995]

anyone now anything about the Clearwater cylinder head big valve head as far as performance? may be interested in putting it on 4.7 stroker. brand new casting with big valves from Clearwater cylinder head. its about 600.00 shipped which seems reasonable if it flows good.

[jeepxj3]

I remember reading somewhere which compared heads, that the big valve head, even with it's 'shrouded valves' flowed better than enthusiast 'pocket ported' stock valve heads. Not counting professional ported heads.

I would go for it.

[CandyCaneXj]

Watch out with them. The oversized valves are shorter and the valve spring install height is only like 1.58 and valve spring seat pressure is over 140 lbs. They are all screwed up. Email or call them. They cannot even give you flow numbers themselves. And THEY DESIGNED IT!!!!!

[Russ Pottenger]

Watch out with them. The oversized valves are shorter and the valve spring install height is only like 1.58 and valve spring seat pressure is over 140 lbs. They are all screwed up. Email or call them. They cannot even give you flow numbers themselves. And THEY DESIGNED IT!!!!!

^^^^ This

A customer brought me one of their heads and noticed the clearance between the top of the valve stem seal and the bottom of the retainer was just a bit over .400 clearance.

[CandyCaneXj]

Wow wonder if anyone had luck using one somehow. I had one but sold it to a friend who still didn't use it yet I'll have to see what that clearance is. We want to have the valve spring seats cut down in order to increase the install height and decrease the seat pressure but first machine shop he took it to said it is not safe to do that as it could be too weak and crack then???? Anyone have any input on how much the valve spring seats can be cut down on these heads?? Apparently there are no 2.00 and 1.57 valves available that are longer. Heard of .050 valve locks that can increase install height but never seem them.

[Russ Pottenger]

I regularly cut the spring pockets down .050 -.100 to get a installed height of 1.700 utilizing Chevrolet LS valves.
Your machinest is correct to error on the side of caution. Many cylinder head castings don't have this luxury.

Fortunately I had a number of cracked cylinder head cores to test how deep I could safely cut the valve spring pockets.

[jeepxj3]

Would these valves work?
Mopar P5249877 intake 1.97" 4.91" 1 groove 8mm
Mopar P5249878 intake 2.02" 4.91" 1 groove 8mm

Mopar P5249880 exhaust 1.56" 4.93" 1 groove 8mm
Mopar P5249876 exhaust 1.62" 4.93" 1 groove 8mm

[CandyCaneXj]

So I took a look at valves. Intake valve: part number P11360JF When I measure it i get 4.905 inches long, .175 valve tip length, .3133 stem thickness(what kind of thickness is that my micrometer seems good???), and 2.00 valve diameter. It weighs 101.9 grams. Seems to just barely have undercut stem and is swirl polished. A stock valve from an 0630 head weighs 111.3 grams........Exhaust valve: part number P4345-HPC 4.925 inches long, .175 valve tip length, .3133 stem thickness again, 1.57 valve diameter. It weighs 93.2 grams. Seems to just barely have undercut stem and is swirl polished. Stock exhaust valve from 0630 head weighs 89.1 grams. So the valves on this head weigh 1170.6 grams a set. Stock ones are 1202.4 grams a set. There is no doubt in my mind that the clearwater head flows good. The intake runner and entrance to chamber is so large. the exhaust entrance is real nice too but the ported 0331 runners seem like they would stink for a stroker??? Does anyone have real data on these valves other than what I measured?? Nothing comes up when I search the part numbers online? Thanks Russ for clarifying you have ground down the spring pockets that far! Jeepxj3 thanks for looking up those valves but it seems what is on this head now is already long valves? Also I did cc the head and I am getting 57-58ccs chamber area. Also this head is tapped for the second threaded temp sensor for OBD1 jeeps. I will take more measurements when I have time.

[jeepxj3]

Looks like could be Manley ?Chevy valves.
Intake # 11360
Exhaust # 11669 or 11621 or 11661 maybe with the head diameter reduced.

[Russ Pottenger]

Looking like they're using a Chevy LS-1 Valve

I'm using the Manley 11360 2.000 intake. 4.874 O/A length .175 tip
11361 1.550 exhaust 4.923 O/A .175 tip

[CandyCaneXj]

Watch out with them. The oversized valves are shorter and the valve spring install height is only like 1.58 and valve spring seat pressure is over 140 lbs. They are all screwed up. Email or call them. They cannot even give you flow numbers themselves. And THEY DESIGNED IT!!!!!

^^^^ This

A customer brought me one of their heads and noticed the clearance between the top of the valve stem seal and the bottom of the retainer was just a bit over .400 clearance.

I measured the one we have I am coming up with about .503 clearance kinda hard to tell with it wanting to move around on the lock a little. Is it safe to machine the retainer a little to get more clearance since the lock does not go down that far?

[Russ Pottenger]

No problem machining the retainer to the bottom of the keeper.

It's a good thing you double checked it. Although you'd probably be ok,
but that's running a little to close for my comfort level.