I am partial to do-it-yourself projects like the rest of us... at least the majority of us. So I have a couple questions for those of you that have done it... What exactly will a more agressive cam do for me? (Hp boosts?, see sig for car) and what does changing the rockers etc do for me... and what can people reccommend for the LG4? As a side note, can the cam be changed with the engine still in the car? What all can I do short of headers with the engine still in the car?

One last question: What exactly does the cam shaft do? My engine experience is with simple two stroke model airplane/yard equipment/dirtbike engines... So please bear with me...

Thanks in advance


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1984 Firebird - Daily driver, 305 LG4, T5 - Hurst short shifter, Edelbrock 600 CFM Performer Carb - Edelbrock Pro-Flow air filter, gutted cat, IROC 16x8 Wheels, Goodyear P215/60/R16, AIWA bargain basement (from Sears of course) CD player, Fuzzy dice, Eight-ball shift ****
Check out my ride here $1600!! Bye Bye on board computer!

First Kill: 2002 Subaru Impreza WRX Wagon (1 person vs me with 2 passengers)

 

If you still have the stock cam, there are several things to consider.
One is gears and converter. the more cam you add, the more gears and possibly a stall converter will be neccessary. A camshaft tells the rest of the engine how to react to a certain RPM. A good cam for a moderately stock 305 would be a Comp XE 256. It will be in the 1000-5200 RPM range. It has .447/.454 lift. More than stock by far.Let's say a cam has .450 lift. A 1.6 rocker will add to the lift of a camshaft. If it's a .450 lift cam with a 1.5 stock rocker, on a 1.6 it will be .480. You get the stock lift, then divide that by 1.5, then X 1.6.(.450 divided 1.5=0.3 then X 1.6 = 0.480)
Now when you add a new cam, it's always good to add new springs. Why? Stock springs are made to go so high. When you add a bigger cam and the sprinsg aren't made for that muvh added lift,you can have valve float. Not be able to pull to the max RPM range. plaus, when replacing the cam, always good to add new springs and lifters of course.
You can add the new cam/lifters and I bet you see some increase.

Most peoples problems, is they want a cam that "sounds" good. More worried about sound vs. how well it works. If you add a cam that is too big for your combination, you actually may be slower. A bigger cam will need intake,heads, gears, stall and possibly a few other mods to work together.
So if you start stepping for further mods, you may want to re-think how much you want to add to this 305.
i would start with a 350 to build while you drive the 305, add a decent bottom end, good cam, better heads, induction and so forth, then just do a swap. But a cam change for now will help.

Summit sells some "shortie" Hooker headers that are really easy to put on these cars. Put some on my brother-in-laws 355 in his '82 Z28. Took a couple hours. Get 1 5/8 diameter, add a good 3" exhaust and you'll be set.

Good luck and I hope this helps some.

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350 4 bolt main, Speed-O-Motive 383 stroker kit, re-sized rods ground for clearance,TRW Forged pistons,10.7:1 compression,HPC Coated RPM intake, Holley 750 cfm carb,World Products Sportsman II heads,2.02/1.60 valves, Comp Cam 1.6 roller rockers, Comp Xtreme 284 cam,240/246@.050 with .540 lift,Crane pushrods,ATI damper,Proform HEI and MSD6A box,HPC coated 1 5/8 headers, 2.5" exhaust with 40 series mufflers,TH350 with Hughes 3000 stall, Powertrax NoSlip Locker, 4.11 gears.

 

Camshaft controls when the valves will open and shut and how far they open.

 

I'm running the XE 256 cam, does a good job but can't really compair to what it's like over stock. Durring the engine rebuild, the stock cam had 4 lobes that were rounded over so I threw in the new cam. It used fall flat on it's face around 3800 - 4000 rpm though. Now it keeps pullin at least to 5500 where I shift.

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'82 Z28
LG4 305 .030 over, performer intake, holley street avenger 670, xe 256 cam, tes headers, 3 inch single exhaust, spintech muffler, 14 x 3 inch drop base k&n.

 

ive got the comp 252 cam in my car , its got decent midrange and if the heads on your lg4 are stock than its the perfect cam , works well with the performer rpm intake man ,