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Discussion Starter · #1 ·
Well I dropped my block and heads off at the machine shop today.I am having the block cleaned and bored .030 over.I am having a basic valve job done on the heads and milled .010 as well as getting the pushrod holes opened up so I can 1.6 rockers.I will be using flat top pistons with 4 valve releifs.The guy at the machine shop said my compression ratio should be right at 9.6:1 - 10:1. I plan on running the LT4 hot cam with full roller rockers.

I have a couple questions.

What valve springs are you guys running with the LT4 hot cam?

What kind of roller rockers are you guys running?
 

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I had a real similar build, but mine is .040" over. Same cam & heads, same flat top pistons

I used the Comp 26918 springs & 787 retainers. They allow you to use stock (un-machined) valve guide posts on vortec heads for lifts up to .600"

I also used Proform 1.6 ratio aluminum roller rockers, they've held up to some pretty harsh conditions, but they are a bit noisy too

Since than I've changed a few things up, now I've got patriot 'vortec' heads 2.02"/1.6" & a comp xr276hr-10 cam, but I'm still using the 26918 springs & proform rollers.
 

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Discussion Starter · #3 ·
Thanks for the info.How do you like them Patriot heads?I have been thinking about a set of them for my build.Got any pictrues of your setup?
 

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I've been happy with them, for a budget head. There are far better heads out there for alot more money, and it's always tough to believe advertised flow numbers. I've found the combustion chambers aren't as effecient as stock vortecs, ie: I advanced the ignition timing to a 36-38 degree max instead of the 34 max I had with the vortecs.

You'll also want to swap out the springs on the patriots to run a roller cam. But for how much I paid for them, I've been happy with the performance.
 

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i am doing a 1990 305 build with vortec heads how much lift can u get outta stock heads with out doing work on the guide boss i have heard .425 and some say .475 anyone know they r 520 casting
 
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