i just recently traded a 98 camaro for an 86 firebird. the firebird has an engine from 1984, what i want to know is if there is any distinguishing features other than the casting number that will tell me if i have an LG4 or an L69?

 

Normally things like the size of the exhaust system (little 2-1/4" for the LG4 vs. 2-3/4" for the L69) would give things away. But in a "non origina engine" scenario it would be tough to tell from something like that, as you can imagine. They used externally identical looking parts.

What engine did your 86 come with originally? Probably the LG4, if it was carbureted. Which means they probably bolted the LG4 exhaust onto it and are running it with the LG4 chip. Which would be a bit of a "Frankenstein" if the motor they swapped in is actually an L69 under the valve covers. The most likely scenario is that the 83 engine was also an LG4 (many more of them were produced than L69 HO motors).

 

i need to run the vin to find that out but there is the sticker that says 5.0 which would mean it had the LG4 initially, all i know is that the guy i got it from bought it with no engine or tranny and put in this engine and a 700r4. the frankenstien seems very correct since the engine runs fine yet theres random wires and a few hoses that i have no idea what they're for...