I looked-up the stock LT1 cam lift specifications, then developed a table that shows the 1.5 and 1.6 rocker arm lift comparisons w/ the stock LT1 cam. Bascially, you will have .030" more lift at the valve with the 1.6s, which is significant! I couldn't find the max lift specification for the LT1 springs, to determine the coil binding safety margin. Possibly, someone else has that specification. I'm not sure the .480" quoted for LT1 springs in a previous post is correct.

Stock LT1 Lobe Cam Lift Valve Lift w/ 1.5 Valve Lift w/ 1.6
Intake .298 .447 .477 (+ .030)
Exhaust .306 .459 .490 (+ .031)

 

thanks again guys,

i read on an impala site that 1.6's give about 15 RWHP, is this correct? anyone dyno before and after with new springs/RR's?

 

Most of the power increase is due to the decreased friction form changing the stock rockers to roller rockers... At least thats what I've been told

 

what does the LT4 motor have for RR's? same factory stuff as LT1 or 1.6 RR's

 

1.6RR's and lt4 springs.

 

thanx

 

Here's a website that shows you a roller rocker install: http://www.streetillusionsracing.com/RR/rr.htm

 

wow, that's awesome.

thanks bud M

one more thing:i see that thunder racing has the crane 1.6 self-aligning RR's, but i'm having a hard time finding the LT4 springs. would GM Performance parts carry this? any other sites that may have them?

 

Those springs are $27 at GMPartsdirect.com. p/n 12495494

 

awesome bud. thanks.

i have one final question about the valve covers:

if using the cranes, will the stock valve covers work?

also, i've seen a lot of guys using comp magnums as well, do these work with stock valve covers without having to modify anything?

 

With anything but the narrow body Cranes you will need to clearance the valve cover supports. Its easy if you have a grinder.

 

hey guys, a couple more questions on this install:

1) do i need a deep socket set to remove the nut on the rocker. i think it's a 5/8 size?

2) do i need the LT4 spring retainers/locks etc with the LT4 springs, or will my stock ratainers/locks work with LT4 springs?

thanks.

 

I'd guess some guys have used the LT1 parts successfully, but I used the LT4 parts to prevent the poissibility of mismatched parts causing an expensive valve spring failure.

 

anyone else use the LT1 parts with any problems?

what about the socket? do i need a deep socket or will a regular one work?

budm, if i were to get the LT4 stuff, what would i need? is there a kit that has everything?

 

http://www.streetillusionsracing.com/RR/Image028.jpg
I dont know do you?