makingPAIN

ok i looked to see if anyone has made a thread about this yet and couldnt find one.. so here is the question, does anyone know of tuning or almost free upgrades that people can do to a 305 carbed motor? everything from timing issues to emissions, air filters.. lets hear what some people have done to help out the little 305..

8t2 z-chev

for stock ,original LG4 305 in my '82 4spd z28, did this:
-converted original air cleaner into functional air induction including making
airbox underhood and making functional hood flaps much like on the
crossfire cars.-
-headers,y-pipe upgrade,3"super single
-upgraded from ultra-mild stock cam to one close to "L69"specs
-carb rejet to compensate for mods
-had to add electric fuel pump as original mechanical pump would not
keep carb bowls full.
I recon these modifications raised the horsepower from stock rated 145
to around 210-220,a dramatic increase in performance still have
fond memories of rocking that 305/4spd combo-still have that engine in
good shape,sitting in the corner of the garage since '94-after 350 '84
vette engine swapped in(hot rodded 305 was actually faster than the
stock '84 vette engine,but i soon upgraded that one too)

8t2 z-chev

for "free or nearly free"without unused parts lying around that can be used
you are pretty much limited to gutting the cat,trying different ignition
timing,air cleaner modifications, and carb adjustments or jetting changes.

makingPAIN

yeah thats what i think to but i have seen a few people asking about this so i thought i would just dtart up a thread and help everyone out

roar

Get Dr. David Vizards books, LOTS of minor matching and grinding of ports, unshrouding valves, Advance the timing as much as you can without pinking, if you have one, replace the fan with an electric one. I guess the 83 cam is much more radical than later's with 305 degrees and ,400+ lift, it feels great!~ The Vett factory headers will be cheap and help.

roar

QUESTION!
do other 83 Z's with HO have the camel heads?

makaveli09

no they have the 416 heads that are originally from the 350 crossfire injection motor

paul_huryk

The LG4 motors suffer from GM choking them down to 145 to 160hp on purpose through a tiny exhaust, retarded timing, and some other items.

The key to unlocking power that is already there is to fix those choke points and let the engine breathe as it should. Headers, 3" cat, 3" cat back exhaust; edelbrock micro-plus timing computer; L69 dual snorkel air cleaner (or an aftermarket one); electric fans (if you have a clutch fan); underdrive pulleys; aftermarket intake manifold; carb tuning...

roar

No wonder it feels so strong! It's hard to not spin the tires when starting and spins happily up to 6k, When I get the carb straightened out and such I'll see what it does in the 1/4.
It NEEDS a LSD!
I have an 8 bolt one but that's a different axel, isn't it?

8t2 z-chev

i think he meant 305 crossfire engine,'82-84 'vette CFI 350 used '624
heads-those have a larger chamber,would reduce compression with a 305.
The L69 "5.0 HO" engine did use a lot of parts from the"'84 corvette"
parts bin though including:
-camshaft from CFI 350
-'vette high flow catalytic converter
-electric fan from "84 vette"
Stick L69s ran low 15s in the quarter IIRC-pretty quick by early 80s
standards Early ads have the L69 rated at 190hp,200hp with premium
gas.Some testers back in the day reconed the L69 was underrated a bit
and cranked out closer to 220 hp under favorable conditions.

Fast355

iTrader: (2)

Probably a few more than that. HP ratings for my G20 van were only 165 HP/240 TQ, but I can attest it ran 16.3 @ 86 in stock form weighing in at 5,300 lbs. It was however setup with factory tubular exhaust manifolds and catless 2.5" true dual exhaust, but had to drive 2 smog pumps stuffed under the hood. Using a simple HP calculator using trap speed or ET and weight suggest 230-260 HP out of the wee little 305 in factory form.