I have a 86 Z-28. I am rebuilding the LG4 back to stock except for the valve train. I am using 416 heads upgraded with 1.94 intake valves, and springs. I will be running headers with no cat, and 2 1/2 exhaust. I am using the stock intake manifold w/1406 edelbrock carb w/dual snorkal fresh air intake & GM HEI ignition. The 700R4 is rebuilt stock w/ shift kit, 2300 stall, and rear is 10 bolt posi w/3.42's. This is not a race car but a weekend cruiser, I want to be able to tease the kids on the street, and also cruise down the interstate @ 80. My question is I would like some input on what would be the best cam to use for this build. Also include custom grinds if they are proven. Thanks in advance for your knowledge.

Steve

 

A compxe256h is a very common one for a mildly upgraded or even stock 305. The xe262h works great with a few upgrades, such as what you are doing.
I'm hoping you're doing some port work on those heads before you drop them on?
Should be a fun car. Are you replacing the pistons at all? If so, are you using identical dished ones? I'd recommend going to flat tops, the style used in later LG4's and in L69s. Also be aware of the compression height, cheap rebuilder pistons put the piston .020" deeper in the bore, so you need to deck the block .020" just to get back to your original stock CR (or else you'll be even lower).

 

Thanks for the info on the pistons. They have not started on my block yet so I will quiz them about that. Could I stay with 1.84 valves or is it important to go to 1.94's. They said they would do bowl & port work on the heads, and put the right springs in. I was looking at Summits K1103 split grind cam, what are your thoughts?????

Thanks, Steve

 

If i was going to use the Summit K1103 grind. i would raise the compression ratio as close to 10:1 as possible Shave heads/thin head gasket/deck block. I would use a hi rise dual plane intake manifold and definatly port the 416 heads with the 1.94's. I would use a 3.73-4.10 rear gear and a 3000 stall lock up converter. Don't be shy on the head porting.

If staying with the 3.42's, stock intake and converter, I would use Crane cams
#113501 Z-256-2 cam installed straight up and use a 1.6 in 1.5 ex rocker set.
Another good cam is ISKY #201262/270-12 262/270 HL hyd.
Again, installed "straight up" using 1.6/1.5 rockers.

To use 1.6 rockers on the #416 heads requires that the pushrod guide slot in the head be elongated a bit towards the rocker stud using a 5/16" rat tail file.
An easy mod to do.

The stock intake manifold has a Q jet carb flange. A Qjet carb would be better overall (with a few mods and jetting) than a edelbrock 600 performer carb that would require a carb spacer/adapter on a stock 305 manifold.

If you want to use a Edelbrock or other square flange carb, get a manifold that will allow a direct bolt on without a adapter.
A Edelbrock "EPS" dual plane manifold is just slightly taller than the stock manifold.
Not as tall as a RPM manifold. More power than a stock or performer manifold.

The 208-221 @.050 .474"-.510"112 LSA hyd roller cam and aluminum intake manifold from a ZZ4 crate 350 would work very well in this application using retro roller lifters.