need some advice on 083 heads and yes im stick with them not going to vortec or anything. they are heavily ported should be close to max and are going on a 350

what size rocker stud are stock heads? and also im running a hydraulic roller 477/490 lift cam with 1.6 rockers, or hoping to at least, im trying to pick out pushrods and springs

im still on a bit of a learning curve here so bear with me, i found comp 981-16 valves which seems that the spring rate and coil bind and all that should be well within reason, ive been told itd be best to have a dual spring with hyd roller cams but i can get away with those as im not spinning it very much.

is that a decent choice? not looking into cutting the heads for larger diameter springs if i dont have to, actually id like to avoid it if possible. also do i need new retainers and such?

and how would i determine what pushrod would be desired? i know that with 083 and 1.6s i may run into the problem of the pushrod hitting the guide, even so i can trim that a safe amount to properly clear the rod so im not concerned about that in the slightest.

any help would be great, take it easy on me springs seem to be a hard topic to grasp, im still on the learning curve but figured id ask for some more experienced advice, also part numbers help alot so i can visualize what yall are trying to explain. Thanks guys!

 

Those 981s are not enough spring for a hyd roller of that size. Nowhere close. They're not really even enough for an aggressive flat-tappet such as a XE or Voodoo with that lift, let alone a XR series hyd roller.

No you cannot "get away with" too little valve spring.

There's AHELLUVALOT MORE to a valve spring's "adequacy", than some "max lift" spec.

I'd suggest either "beehives" such as these from Texas Speed http://www.texas-speed.com/p-4040-pr...pring-kit.aspx (you'll need different keepers), or Comp 986 which will require some machining.

You determine push rod length the same way everybody else with ANY heads and ANY rockers does: with a pr of "solidized" lifters, a pr of "check" springs (something real light weight, yerbasic plastic bag with 2 springs in it from the #20 or #48 store will work fine), and an adjustable push rod. You build the motor, install the heads, and mock up a cyl as described. You then select the next shorter increment of push rod from the one that gives you the narrowest possible "sweep" of the rocker across the valve stem, ignoring where on the stem the pattern lands.

The push rod won't hit the guide. The guide is what the valve passes through, down inside the valve spring, several inches from the PR. However the PR may hit the intake side of the hole in the head that it passes through, and the heads should therefore have the holes elongated.

 

i meant the holes in the head dont know why i said guide oh well.

so would it be a better approach to run 1.5s and keep lift at .447/.459

odd thing was summit themselves reccomended the 981's i was previously looking at a set of howards but the spring rate was 410 or 410 which i thought was a bit much.

 

What cam?

Summit doesn't know diddly about cams, besides what sells well. They don't design em, make, em, understand em, or warranty em. (warranties get passed back to the mfr) All they do is sell em. Pay no attention to their recommendation.

 

stock lt1, engine wont be super high hp, revving or anything else, just looking for a stout driver for my k10 and ive always likd the lt1 cams for a bit of pep plus i had one from a friend, low miles, good shape, also had the 083s freshened up already sitting on a shelf.

 

Oh...

981s will be fine for that. For any of those, really. (there's at least 4 such that I know of) Not a "performance" piece by any means; not appropriate to any sort of "max effort" build, at any level.

Sorry, you got me thinking you were really trying to do something ... significant.

 

hey man be nice, and no nothing special about it, just nice mannered big old 72 k10

 

This is a Camaro/Firebird board.

Thought you were working on a Camaro or Firebird.

Sorry, my bad. I'll take my leave and say goodbye now.

 

i forgot to mention it was going in my truck, ive had a few thirdgens and i just like it more over here when it comes to engines because theres guys like you and alky, and 57kid and a bunch of other guys who know what theyre talking about.

with those springs do i need different retainers though?