Chevy valves-J heads rocker geometry tricks

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TheCrackHead

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I have a set of J heads that were given to me by a good friend who wanted me to go 'all out' with a port job, the deal was they are free and if I hit water who cares, so all out I went and after that I had them pressure tested, seats installed int/ex, 11/32 bronze guides, spring pads cut for engle doubles, milled, 5 angle valve job.

Pics below are before any machining was done -already had int seats- .

But the real question is having increased the installed height .200 how do I fix the rocker geometry?, is milling the stands and fabbing new ones mandatory?

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I am sure you'll need to use support blocks. but you may be able to have T & D make up a set of 8008 straight rockers (non offset) for your longer valves. The upside is you can get any ratio you want. Not sure on the cost tho. Simply raising the shaft by almost 1/4" will make the stock fit type rockers useless (too long).
 
no, offset refers to the rockers pushrod cup vs rocker tip. Bigger port W2 and some Indys, plus I think Brodix use an offset intake rocker so the PR pinch in the port can be shaped better. You will want to elongate the pushrod holes too. There are offset rocker stand setups. I've never used them, but I'm sure they exist. I don not know if they are made to keep the shatf oiling system. I'd think they would not and you'd have to run oil thru pushrods and lifters.
 
I get all that, I meant rocker shafts with the mounting holes offset, have you seen them?
It does sound like I have to have the stands milled flat and buy blocks.
 
[But the real question is having increased the installed height .200 how do I fix the rocker geometry?, is milling the stands and fabbing new ones mandatory?[/QUOTE]

What type of chevy valves did he use?,small block +.100 valves are only .025 longer than std. la valves and std. small block chev valves are .080 shorter.
 
I used chevy +.100 valves in a set of j heads.......+.200 seams to longs..
 
I've never had to use offset support blocks. . I wouldn't have used then or gone that far on any factory head. BJR probably has used them.
 
Have you flow tested them yet? What are the dimensions of the pinch and the port entry? Most of the maxxed out iron stuff I've seen has been filled floors and relocated pushrods along with welding in the chambers to close them off. And those were pictures in books...lol.
 
TheCrusher said:
Really I gotta check'em before jumping to conclusions but wanted to hear others experiences with 1.85 heights and factory iron.
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Ive seen alot of la heads w/chevy valves installed and Im baffled,so your spring height is 1.85?,seems maybe the shop milled the spring pads down too much?.The reason I ask is with +.100 small chev valves you should be closer to 1.7 and if its the pads milled down then no problem with rocker geometry just the spring height-just trying to figure it out.
 
moper said:
Have you flow tested them yet? What are the dimensions of the pinch and the port entry? Most of the maxxed out iron stuff I've seen has been filled floors and relocated pushrods along with welding in the chambers to close them off. And those were pictures in books...lol.
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Believe me I was thinking about going further but as was the quest for flow in the 260-280cfm so was the concern for $$$$$.lol
I also thought about removing the pinch and pressing brass/copper tubes then flattening them, but I'm not doing that crap, I have a feeling when these hit the bench they be enough for my stroker's target HP. we'll see, I'll definitely post the results.
So far I have $840 and thats all together assembled.
 
lead69 said:
Ive seen alot of la heads w/chevy valves installed and Im baffled,so your spring height is 1.85?,seems maybe the shop milled the spring pads down too much?.The reason I ask is with +.100 small chev valves you should be closer to 1.7 and if its the pads milled down then no problem with rocker geometry just the spring height-just trying to figure it out.
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I would think the same also, I know the spring pads were cut for diameter and spring height so I will find out today hopefully.
 
Heres some Js with the pushrods moved

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The motor made 500hp 500ftlbs using a stock intake, catb and exhaust.
 
Nice X heads, looks like you welded the exhaust floor or something.
Good job with the tubes, did you know that some heads have the push rod hole over more than others? and if you can find 2 you can remove almost the whole thing as much as those x heads?
I've found this on 75 and up 360 heads, I don't like the exhaust floor on them that much though.
 
I'm pretty sure that's Dwayne Porter's work, right Adam? Looks like epoxy on the PR pinch, and floors of the ports welded. I would be very surprised and impressed if those Js as pictured hit 280.
 
I believe those are Greg Gesslers heads and they arent his max effort FAST heads either.
 
thats some good head work, it don't matter who done them, how much does a job like that cost?
 
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