Hello to all. I have a few questions. first of all i have a complete 97 vortec motor with speed pro flat top forged pistons, comp xe270 cam around .500 in of lift on int and exh, elderbock performer rpm intake, stock crank & rods. i also have a street avenger 670 and a 750 carb,and long tube flowtech headers(i know they are not the best) . ok first question, i want to order me some comp springs, but i've been searching trying to figure out this thing about cutting down the bosses. Whats all involved in this? do i just take the heads and springs to the machinist and the handle all of that, or is there something i need to mention? i already had a 3 angle valve job done and milled .010. i'm wanting to get the heads milled another .010 to bump compression a little more. would the stock push rods be ok with .020 and this particular cam? also i'm running the stock roller lifters.

I will be adding 1.6 roller rockers, what else do i need to do to the heads in order to run these? also will 2.5 dual exhaust be sufficient for this setup? i have a 26-2800 stall in my trans and will most likely be running 3.73 or 4.10. what do you guys suggest. thanks in advance and sorry for the long post

 

Welcome aboard thirdgen.org.

Take the heads to a competent machine shop. They should have a cutter that will do three things at once for you - cut down the tops of the guides, size the tops of the guides for positive-type valve stem seals, and prep the spring seats for "good" valve springs. They can then assemble the heads for you with new stem seals, the new springs (and retainers, I assume), all properly set up.

1.6:1 rockers may not help you much, if at all. The Vortec ports stop increasing flow at around .50" lift, so the extra .03" lift isn't going to help you.

What cam exactly do you have? Is it roller lifter?

2.5" duals should be plenty for this engine. The stall should be fine as well (depending upon what the cam really is).

 

well i have the cam card i thought it was the comp xe series but its a comp xr270
218/224 @.050 on a 110 .495/.502 lift.What's the difference between the xe270 and the xr270?

 

XR is roller lifter.

 

what valve springs kit would you recommend for these vortec heads? and those are the cam specs in the previous post

 

If you get the spring seats opened up to 1.43", the Comp 986-16's. The 740-16 retainers and 611-16 locks wouldn't be a bad idea, either.

 

So when i take the heads back to the machine shop with the required springs,locks and retainers he should know what is required to install them? correct? and also what about the push rods? will the factory length be ok with a .020 mill head?

 

The factory length pushrod should be fine. That's hardly any milling. Small base circle cams and aftermarket heads are when you need to start worrying about that.

If you take the springs & heads to the shop, and they don't know how to properly prep and assemble them, you're at the wrong shop. Assuming you take them the proper parts, of course.