THIS IS A PROJECT I JUST FINISHED. these are some vortec heads i will be setting up with LS1 springs to run higher lift. first i will show the tools needed to buy for this job. these can be bought here. http://www.compperformancegroupstores.com/store/merchant.mvc?Store_Code=PH on the left is the cutter and on the right is the stud puller and tapping guide
first i rounded up my box of old rockers and nut's i used the old nuts to remove the press-in studs from the heads, using my new stud remover..after i pulled the stud half way i backed the nut off and put on 6-7 washers to keep the nut from bottoming out to pull the stud completely out..did all 16
next what took the longest was figuring out how to set up the head on the drill press to level it.. I USE TWO 7/16 BOLTS WITH NUTS UNDER THE HEAD USING THE HEAD BOLT HOLES. ADJUST TILL LEVEL set my drill press on the lowest speed 750 rpm. set the depth to keep all the cuts the same. your cutting the thinkness of a stud nut and guide plate. approx 3/8" i cut all 16 while i had the set up going. used cutting fluid every thing went very well.. you be the judge
well after cleaning up the chip's and sitting my small drill press back under the bench, i set up to drill and tap the holes using my new stud puller/tapping guide.. also bought some brand new 7/16 course taps for the job install the block using the stud pin supplyed and start the tap go about half way.then you can remove the block and complete the tapping job on each hole. do all 16 it's lots of fun
next after the tapping process. it's time to install the studs and guide plates. i cleaned the holes with starting fluid to remove the cutting oil, so the locktight would set-up nice. i used it on each stub thread and tightened to 60 ft lbs.
well i hope someone get's some good from this post. i have also drilled my own steam holes in these heads for use on my 400 ci chevy block. i would be happy to explain if someone would like.. i also have all the pictures of the LS1 spring install i did on these vortec heads. if someone would like. hope your having a great day. your new pal mark
A quick explanation might be in order as to WHY one would want to do this. At what cam lift/spring tension/RPM should this be considered mandatory? I know it's (as Martha says) a "good thing" for any high performance engine, but being a cheap bastard I like to know when I'm paying for a necessity and when I'm paying for insurance, or "cool factor".
The biggest issue with stock vortec heads is that they are limited to about .420 valve lift. This varies for different heads. They require new springs and retainers with the correct seat cutting to allow larger cams. Screw in studs and guide plates are a very wise investment when you plan to increase the functional motion of the valve train by as much as 30%, especially given the increased spring pressures that come along with this. Pressed in studs can work out of the head, pushrods can bend, etc. I expect to install screw in studs for the additional security, but may use the late model rockers that self align instead of guide plates. That will be a discussion for my machinist. Thanks Mark. Your timing is perfect.
Nice tech article. The only thing I could add is that it might be a good idea to chamfer the holes slightly before doing the tapping. Chamfering helps to align the tap down the center of the hole, and it keeps the top thread from tending to "pucker up" making a bulge in the area that's supposed to be machined flat. But cast iron isn't very malleable, so it probably doesn't bulge up much anyway.
no problem man. i did do the ls1 springs and retainers, locks, from comp cams. installed it all my self. it's amazing what you can do if you take your time and do some research. nothing better for a slow winter saturday in the garage heres some more pictures, i drilled some steamholes my self too for use on my 400 sbc. that went very well. i made some goofy head stands that made working on the heads very easy. heres a very cool spring compressor i bought .that things a snap (the big one) compaired to the little one. i plain to do some 882's next (screw in studs)
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