On a SBC with Harland Sharp rockers and a 30-30 (.485 lift) Without having the engine togather i want to build spacers to run the Z-28 or 70's vette valve covers, so has anyone done it or how tall are the minimum tall valve covers i can run??
To determine how much space you need you can mock it up with the rockers and VCs you want to run and modeling clay. Place a 1/4" thick piece of clay on the rockers and install the valve cover with washers between the cover and the head. Rotate the cam then remove the cover and look for contact marks in the clay. Decrease the washers and retest until you have marks in the clay. Once you establish this distance you can add the amount of clearance you want. Measure the thickness of your washer pack and head for the machine shop. Don't forget that you still have the thickness of your clay after the imprint to take into consideration. How much ***embly do you have done? Cam lift will play a role.
i think the bulkiness of the rockers and the poly locks are the issue...always seemed to be the case with them for me.... brandon
I don't know about H/S rockers, but I use CC 1.6 Pro Mags on a SBC with .525 lift and clearance was not an issue with either the stock LT1 composite covers or the cast Morosos I use now. Comp Cams Pro Mags are a stainless roller rocker though, not a billet aluminum like most. My valves are a tad longer than stock but I still use stock-length push rods.
Back in the early 70's ... Moroso made a set of aluminum cast valve cover spacers so you could run roller rockers and a stud girdle with the original Z-28/Corvette aluminum valve covers. The ones they sold were about 3/4 of a inch thick. I have owned two or three sets of the spacers ... over the years. Maybe eBay, a old racer's auction ( or .. maybe a want ad here in the cl***ifieds ) would turn up a set of the Moroso ones ... Now ... you can buy a valve cover adapter to use a old style valve cover on the 87 up center bolt heads ... If you just ran longer studs into the heads and thru the valve cover spacers ... you could bolt on your early Z-28 covers and clear your roller rockers.
seems like the later model heads have a taller rail on the head for the v/c's...i know a friend runs some roller rockers on his lt1 with out tall valve covers...thick gaskets helps too.... brandon
I got away with running roller rockers with Z-28 covers. I glued 2 or 3 gaskets together and broke off the drippers inside the cover. You don't need the drippers anyway with rollers... Now I think felpro makes thick gaskets with steel in the center that may work. Best way is to install the rockers and set the covers on to see how much daylight shows between the cover and the head. Jeff
Get an old stock valve cover, cut the top out so you can see what you are going to need. They will also serve you when you prime the motor with valve covers removed so the oil won't run down your heads.
I run H&S roller rockers, (no stud girdle) using Edelbrock performer RPM heads which I believe have the same rail hgt. as a stock chevy head, A serious roller cam and early corvette 7 fin covers using 2 Fel Pro 5/16" gaskets glued together with High Tack. Even with some major stupid shifts I do not hit the covers. This set up gives me about .120 at high point on the 1to6 rockers.
Lots of variables here. I agree with dropping the valve cover in place minus the gaskets to see what you are working with. I run a set of mid 60's finned aluminum Corvette valve covers over my 1.5 roller rockers with a 560 lift cam. It has a set of 1/4" thick Mr Gasket gaskets. I am using Dart Iron Eagle cylinder heads which have slightly raised rails which obviously help my situation. Give it a go with several different gaskets by themselves or stacking as necessary to see what you need to do before making any decisions.
I agree with stacking the gaskets as required. I looked at a set of about 1" spacers at Hudson Performance the other day, they're an Alliance Vendor, but I think they totally ruin the appearance of the early covers. They were in stock there if you need them.
I got shaft mount conversion rockers on the last chev I built with stock stamp steel covers. 630 lift roller tappets. Talk about a sleeper Hah this thing is the schizzz>>>>.
As for getting the spacers, i run a Waterjet CNC and i've already drawn up a program, faster than even ordering a set
If you get the aluminum spacers and they ruin the look, you can paint them the head color and it kind of hides them. If you go fast.
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