the ecm from the l69 is going to need swapped right?
will it plug up the the lg4's system? or do i need to switch harnesses too?

what else do i need or should i swap
im going to do the exhause too since the l69's was a lil thicker and is still n good shape?

 

The ECM from the L69 should be used (a little better timing curve in the PROM). The harness should be the same, though it would be best for you to compare them.

 

well i have the motor out
man the guy runnint this was a tard
had most of the vacuum system removed
so i have no idea how this goes back together right

anyone offer me some advice on what all wires need to be hooked up to run this motor?

 

Which engine is out?

Wiring required and vacuum routing should be the same for the two engines.

 

The exhaust will be helpful (I went that route). Check the pic in the following link. The pipe on the left is the LG4, the right L69:

https://www.thirdgen.org/techbb2/sho...hreadid=216368

JamesC

 

its supposed to be an l69 all the badging on the car claims it
but i got the block out and its stamped lg
it has the thicker exhaust
so is it an lg4 or an l69
front and rear main seals seem to leak
metal shavings in oil

looks like im gonna just clean it up paint it
and pop it

its not realy worth sinking money into
either way

im not hooking back up the vacuum system
im going bare bones with the re-installation
im not worried about emissions
people in central illinois dont care
just a weekend joyrider

 

oh btw the stock lg4 from the 86 trans am has been sitting on my garage floor since i was 15
i yanked it and didnt know what i was doing
lost parts bolts hoses everything

so young so dumb
had valvetrain problems
4 flat lobes on cam
2 of the cyl had a ring grove that you could pop a top off a bear bottle with

damn lg4's

im not going through all the trouble to make this emissions legal

just bare minumum so it will run

the car body had 96k on it the other engine has 150k on it
so its not worth doing this anyway other than to just get the car running

not very often you see a 20 year ole car with more miles onthe engine than the body lol


future plans are nat asp 350

 

The blocks are the same, LG4 or L69. If there is an "LG" stamped or cast into it, it stands for something else.

 

wow how can i tell if its actualy the l69
cause this car who knows what it is
the numbers seem to match up to my lg4 exactly
every stamping behind the heads is the same
is there some other difference?

 

i found this information
and the one that was in the car seems to have been an l69 by this reference
cause it had the flattop higher CR pistons

dunno

http://www.darklair.com/monte/l69.html

Starting with a standard issue Chevy 305 small block, here are some interesting notes:

* both use aluminum intake
o early LG4 models had a cast iron intake however
* both use the same heads
o casting: 601
o 58cc chambers (60cc ?), 178cc runners (158cc ?)
* valve size in L69 heads were larger
o L69 : 1.84/1.50
o LG4 : 1.76/1.46
* L69 has 9.5:1 CR (flat tops) [these numbers changed]
* LG4 has 8.6:1 CR (dished pistons) [these numbers changed]
* L69 has a special cam, from the L-81 Corvette (hydraulic)
o This is NOT a roller cam
* L69 uses a performance calibrated PROM
* L69 takes advantage of special exhaust/catalytic converter
* L69 takes advantage of a higher stall torque converter
o L69 : approximately 1900 RPM stall
o LG4 : approximately 1200-1500 RPM stall
* L69 uses a better fuel pump (from the Z/28)
* the changes in the L69 setup yielded *roughly* 30 more horse power
* the same changes actually yielded slightly less peak torque for the L69, but had the advantage of a flatter torque curve overall

 

https://www.thirdgen.org/techbb2/sho...hreadid=261488

JamesC

 

It could make a difference what the L69 or LG4 was installed in by the factory. The comments made here assume the engines were installed in 3rd gen f-bodies.

 

pictures below
if you can tell anything by the casting numbers let me know if its the l69 for sure