exess valve guide protruding into the bowl?

scxr7

Registered User
I recieved my 93 sc heads today. after getting a port and polish job along with decking, cleaning and a chevy valvetrain including 1.94intake and 1.55exhaust valves. the intake flowed 230cfm at .400lift and something crazy like 290cfm at .700 lift. I told him I'd have to see it to believe it. he said "I'm just letting you know the numbers I got, I'm not making this up". I asked for a printed copy so I can post up on here to see if you guys think its legit.

other than the high flow numbers, the only other issue I have with the heads are the valve guides. He didn't touch the guides after installing them. what I mean by this is that he didn't grind the extra 3/8" off the bottom of the guide, its still sticking out into the bowl. he said he left it like that for flow purposes. it creates turbulance which helps mix the fuel and air, if he were to grind that down flush with the roof it would allow the air/fuel charge to ram into the back of the bowl which would create a fuel puddling effect, so its actually better to leave the guides the way they are.

What do you guys think about this theory? should I have the valve guides ground down or leave them the way they are?
 
Keep the stock valve guide length helps the life span of both the valve and the guide. In theory shorter the valve guide the quicker it will wear out, or so I'm told.
 
My opininon...

Keep it like it is. Better to have too much guide than not enough!! I don't think it will represent much more of a restriction in flow and just the valve itself would if the guide was cut back.
 
I don't think it will make a ton of difference either way. I would leave it for reliability. And the blessing of not having to mess with the heads anymore. :D

Oh, about the flow numbers ... You need to know the vacuum pressure at which the reading was taken to compare between heads. And even then, it's hard to compare, because there might be subtle differences in the test rig. The only true apples-to-apples comparison would be to bring him another head as a "control" and have him flow both.
 
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I recieved my 93 sc heads today. after getting a port and polish job along with decking, cleaning and a chevy valvetrain including 1.94intake and 1.55exhaust valves. the intake flowed 230cfm at .400lift and something crazy like 290cfm at .700 lift. I told him I'd have to see it to believe it. he said "I'm just letting you know the numbers I got, I'm not making this up". I asked for a printed copy so I can post up on here to see if you guys think its legit.

other than the high flow numbers, the only other issue I have with the heads are the valve guides. He didn't touch the guides after installing them. what I mean by this is that he didn't grind the extra 3/8" off the bottom of the guide, its still sticking out into the bowl. he said he left it like that for flow purposes. it creates turbulance which helps mix the fuel and air, if he were to grind that down flush with the roof it would allow the air/fuel charge to ram into the back of the bowl which would create a fuel puddling effect, so its actually better to leave the guides the way they are.

What do you guys think about this theory? should I have the valve guides ground down or leave them the way they are?

I wouldn't worry about the valve guide, messing up the flow.

I agree that the flow numbers are very high. I had a set of heads with hogged out intake runners (required handmade gaskets) and the same sized intake valves (1.94) that were worked on by three differnt people who were very good at porting and the best port flowed something like 240 @ .600 and flow decreased above that lift. The CNC ported large valve heads I've got now flow an average of 235 intake and 195 exhaust.

What kind of numbers did he give you for the exhaust side ?

David
 
I need to call him back to get the exact exhaust flow number.

I gave him a set of my stock heads to flow as well so there will be somewhat of a compare and contrast.

I didn't ask him which port he flowed either. wether it was the middle port or not I don't know.

I posted up another thread about my cylinder head surface if you guys could check that out for me. I'm not too sure about the finish.
 
I need to call him back to get the exact exhaust flow number.

I gave him a set of my stock heads to flow as well so there will be somewhat of a compare and contrast.

I didn't ask him which port he flowed either. wether it was the middle port or not I don't know.

I posted up another thread about my cylinder head surface if you guys could check that out for me. I'm not too sure about the finish.

Saw it, the finish is too rough to use MLS gaskets, and the pitting in the castings is normal. These castings are crap compared to a good aftermarket head like AFR or Trickflow.

David
 
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