CFI-EFI is right, on all counts, and Z-28 springs only cost about $40 a set. You should also replace your valve-seals while you got'um off. 
85 Rocker Questions..
Thread Starter
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Joined: Aug 2004
Posts: 98
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From: Miami FL
85 Rocker Questions..
I have a 85.. I know that a 85 is still the old style block.. My question is Can I just throw a set 1.6 roller rockers on this.. I probably need to replace the springs right.. what springs and rockers would you recommend.. also what gains do I get by doing this.. also this self aligning tip thing has me confused.. should they be self aligning or not. Any sugestions would be great.. Thanks.. 
Instructor
Joined: Aug 2003
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From: Soddy Daisy TN
I have an 85 with roller rockers but they are 1.5s. I have Edelbrock alum heads with guide plates, non self aligning. If you plan to use the stock iron heads, I'm not sure if the holes the push rods go down through are big enough to accomodate the extra travel geometry of the push rod with a 1.6 rocker arm. They may need to be slotted out. I would also go to a different springs other than stock because they will be compressed more with a 1.6. Someone else may be able to lead you in a good direction as to what brand to buy. From what I was told when I asked these same question with just changing the rocker arms to 1.6's from 1.5's wont give you much...5 to 10 hp,... maybe. If you have a roller cam and lifters you would see more than that but I don't know if your stock heads would work as I said earlier. Put some alum heads on and then go with the roller rockers. Then it would be worth the time and trouble.
Melting Slicks
Joined: Jun 2004
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Originally Posted by rsauron
I have a 85.. I know that a 85 is still the old style block.. My question is Can I just throw a set 1.6 roller rockers on this.. I probably need to replace the springs right.. what springs and rockers would you recommend.. also what gains do I get by doing this.. also this self aligning tip thing has me confused.. should they be self aligning or not. Any sugestions would be great.. Thanks..
Yes they'll fit.
You should replace the springs (as the old ones will be under more stress with new rockers), but you do not have to.
1.6 ProMag's (available from summit) seem to be the most popular, and best fitting. For springs, I personally like the edelbrock ones...
THey should be self aligning, although you'll hafta remove, then replace the guide plates... there is another thread on this that goes into more detail... do a search... from what i'm told you can expect between a 10 and 15 chp gain from just 1.6's due to the stock rockers being very weak/flexable... The 85's cam is supposed to be pretty well designed, you shouldn't hafta mess with that
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Joined: Aug 2004
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From: Miami FL
Thanks for the info... The 85 doesnt have a roller cam does it.. I thought it was a Hydraulic Flat-Tapped.. right or am I wrong.. What size studs are on these heads.. 3/8 right.. thanks again
Race Director
Joined: Sep 2000
Posts: 17,298
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From: The Top of Utah
Originally Posted by rsauron
Thanks for the info... The 85 doesnt have a roller cam does it.. I thought it was a Hydraulic Flat-Tapped.. right or am I wrong.. What size studs are on these heads.. 3/8 right.. thanks again
Your iron headed '85 uses 3/8th", press in studs and NON self aligning rocker arms. The push rods are guided by slotted holes cast into where they pass through the heads. The slot, very well, may need to be elongated. Check, very carefully, for adequate clearance. Your existing springs will suffice, if they are in good condition. If you replace them, don't go nuts with the pressure. You're likely to pull the studs out of the heads. Something like a stock, older Z28, spring, with around 100# seat pressure should do nicely. Oh yeah, you DO have a hydraulic flat tappet cam.
RACE ON!!!
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Instructor
Joined: May 2004
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From: machesney park il
1.6 rockers on the 85 iron heads will get the stock springs to close to coil bind.you will also have to elongnate the slots the pushrods go through.another way to go is comp cams 1.52 magnum roller tipped rockers,a little more lift without any mods needed.if you are going to go to all the trouble of useing 1.6 rockers i would just go with a aftermarket alum head like the edlebrock.it all depends on how much $$$ you want to spend.
