How much are you guys decking your heads? What valve sizes?

I dont know what valve sizes mine are, and the only thing I know about them, is the little bit of info the guy that did them gave me. Said they are decked .050, but are deshrouded, so its really like .045 ish.

Hope that helps a little bit. Good luck.

I want to get some head work, but i don't want to go crazy with them. Im running 26.5 mph at 3800 rpm right now. Id like a little more speed and load carrying. I make loooong runs when fishing so i want it to be reliable.

Is .045 safe?

Yes

Go with pistons and rods. Decking the heads changes the rocker position. Pistons and rods are better

The rocker position can be fixed when decking the heads to keep the same valve train geometry.

Yes you can keep the same angles.

i have a guy local that does machine work on all the race V8 motors around here and he said no problem to do my heads. He said $75/head for port and polish and lap the valves is that a fair price? so deck .045 or not?

my twin thumbs and today's cellular technology

Yes that is a good price. Just make sure and tell him not to take any material out of the runners.

Anyone ever tried getting everything Extrude Honed before?

You would still have the casting defects with the extrude hone and would be able to reshape the runner to bowl blend. There is a company that takes a liquid metal substance and poors it into the intakes to make it as smooth as a ported and pollished runner would be, I want to say they charge $75.00 per runner.

You think it's worth 150 bucks to have mirror smoothe intake ports? Cool process, but I don't know if I'd pay 150 bananas for it. One of the best head guys in the country doesn't even polish the ports in his race heads anymore. He uses a messed up bent burr bit and finishes all the runners including intake in a scalloped looking finish. Sees gains on every kind of application he's built motors for from stock eliminator class small blocks to big inch multi kit nitrous motors. Just some food for thought.

decking of your choice, just reassue him that these motors do not have 8 cylinders so he needs to clean out the casting defects in the runners, do not hog them out.

I do not think that you need to go into the intake runner and polish it out with 220 - 300 grit abrasive tool, but if you know what you are doing you can make a good finish with 120 grit. The flow path and port velocity is more important that the actuall finish./

So are the majority of the gains from decking or from increasing valve size.

Are the leak down failures from inferior factory valves?

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U are seeing gains from have your valves sealing and not leaking by . The stock valve seats are horrible. And obviously if you deck you will see noticeable gains.

The leak down is from seat inconsistency in sloppy briggs heads.

Not to sound like an idiot but is it Ok to keep the factory valves if they have been lapped?

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Yes but it will start leaking again

If you wanna be really cheap have them decked, knock the heavy casting marks out with a die grinder or have the machine shop clean em up, buy stainless exhaust valves, lap all 4 valves in (its gonna take some time, you can usually see daylight in the gap on the exhaust side) and shim the springs .120 an you're done. For probly around 250-300 bucks.

Im not concerned about cost really. Turn around time is more important since i use my boat a lot. So stock sized ss valves or change sizes? Thanks for all the responses so far

Can people start posting part numbers too?
2.02 intake valve, great. P/N?
1.60 exhaust. P/N?
What about the valve seats?
What about the valve guides?

I've sourced stock SS Manley valves.
And I'm in contact with Manley about getting some custom valves,
I'd just assume buy an off the shelf valve, assuming it's material.

I'm offshore right now but I'll share the rig I have made up for
knocking the high spots off in the runners, when I get home.