Originally Posted by 300Deluxe
I got the spring specs from both Jegs and Summit's product description on their websites. I want to say that I looked them up at one time on Holley's website as well. I'm guessing that they can't be found there anymore.
It's a relief knowing I won't have to purchase new valvesprings. I just wanted to be certain.
What about pushrods? I plan on purchasing a length gauge. I was told that the stock pushrods wouldn't work. I've read that with the proper length, that the tip of the rocker arm should be centered over the pushrod. I *think* this came from article on Comp's website. I may have to dig up the link. Is this something you eyeball to see that it "looks" centered? Or is there a more precise way of measuring?
Also, I'll pose this question again: With such a thin head gasket, do I need to be concerned with valve-to-piston clearance?
Apparently Holley has sold off Lunati Cams to a new company. But the new company has not launched a internet site yet as far as I know. I think thats why most of the Lunati stuff cannot be found on the Holley site any more.
But if you enter a Lunati part number in the Holley search box you get the tech info page you're looking for, for Lunati stuff.
Some, (but not all) after market heads have a thicker overall height from the deck surface to the relative height of the rocker arm stud boss. Usually requiring a +.100 longer push rod by default.
You'll have to assemble the heads on the motor and see what needs to be done for push rods.
Valve to piston clearance will not be a issue. You have tons of room with the cam, heads, gasket,pistons and block you're working with. SBC Valve to piston clearance typically becomes an issue when the (flat tappet) cam is bigger than 250@.050" on tight LSA (lots of overlap) and the heads and block have been shaved quite a bit. I check all roller cams larger than 230@.050" just for grins.
On a previous engine project I built a very hi compression 350 with flat tops with a decked block .018" and the thin .015" head gaskets + maximum flat milled 305 heads + a pretty big solid bracket race/oval track cam 256-264@.050 105LSA and the measured V/P clearance was right at the minimum required for safe high rpm engine operation .090" Thats cutting it close. You're no where near that on your build.
The specs for the 1.47" springs: Did that info come with the Summit heads?
When i checked out these heads at Summit, I did not pay a lot of attention to the literature included in the box. Was more interested on the casting and machining quality of the heads etc.