Hello

Im planning to do some mods to my 1989 5.7 TPI. [bare with me if this is a common question but this is my first motor]

I am doing a 3 inch exhaust with longtubes. Edelbrock base with SLP runners and an AFPR. I am also going to port the heads.

I dont have a clue about lift and duration etc. so i was hoping someone could give me an idea of what cams/springs [roller cam]will best suit my plan. I need to pass emissions and this is a daily driver so long as there is no snow. I would like to upgrade my peformance but not loose all of my driveability.

Also Should i get some 1.6 roller rockers as well? If so which ones?

any info would greatly be apreciated
thanks

Speed

 

Iron heads in stock form can only handle lift up to about .470" before you have interference between the valve guides and valve spring retainers. You can address this if you have the heads reworked by reducing the height of the valve guides. You'll also want to replace the press fit rocker studs with screw in studs for reliability. Here's some starting points for you to research. A search should turn up more info than you'll ever want to know.

Lift less than .480" - Crane 2032, Accel/Lingenfelter 74216
worked heads - Accel/Lingenfelter 74211, Competition Cams 264HR, 266HR, and XR264HR, GM ZZ4, TPIS ZZ9

Roller rockers are a nice upgrade over stock. Pick your rockers and associated ratio once you've picked a cam. You want valve lift to be compatible with your valve springs and to enough valve to pistion clearance. 1.5 rockers may be all you need depending on the cam you pick.