how to identify a 305 vs a 350
08-02-2017, 10:16 PM
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Car: 1991 Pontiac Firebird Trans Am GTA
Engine: 5.0 TPI
Transmission: 4 Speed Automatic
how to identify a 305 vs a 350
Im 17 and am currently working on basically rebuilding this car from the ground up. My dad has got the car in a trade when i was 8 or 9. The odometer reads 220000 but he said if he remembers correctly the engine was rebuilt or changed. Hes not a car guy and this car has been collecting dirt the past 10 years. I got the car started but it would only run at full throttle or else it would die off. So i purchased new fuel injectors and am currently waiting to install them. after that it got me thinking whether i ordered the correct injectors. any tips that i can get on identifying would be great. The vin number points to 305 but i just want to be 100 percent. thank you
08-03-2017, 08:34 AM
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Re: how to identify a 305 vs a 350
The only way to identify a 350 from a 305 with absolute certainty, is the block casting number.
It is conveniently located in the most accessible and conspicuous place available: on top of the bell housing flange, behind the driver's side head, kind of up above the oil fiter. [/sarcasm] You might be able to take a photo with your phone or something, if you can't warp your eyeball down to it somehow.
The VIN of course won't help: it stays the same even after a motor swap.
Get that number and post it, we can then tell you with absolute certainty whether the block had a 3.736" bore (305) or 4.000" bore (350) when new.
On almost all newer blocks there is also "5.0 LG" or "5.7 LG" next to that number. That's also pretty good evidence. No idea what the "LG" part of it means, that's just what they cast there... seems like a total waste to cast the same thing on every single block as part of some sort of "identification", but w/e. That's just what they did. I assume no responsibility for whether it "makes sense".
It is conveniently located in the most accessible and conspicuous place available: on top of the bell housing flange, behind the driver's side head, kind of up above the oil fiter. [/sarcasm] You might be able to take a photo with your phone or something, if you can't warp your eyeball down to it somehow.
The VIN of course won't help: it stays the same even after a motor swap.
Get that number and post it, we can then tell you with absolute certainty whether the block had a 3.736" bore (305) or 4.000" bore (350) when new.
On almost all newer blocks there is also "5.0 LG" or "5.7 LG" next to that number. That's also pretty good evidence. No idea what the "LG" part of it means, that's just what they cast there... seems like a total waste to cast the same thing on every single block as part of some sort of "identification", but w/e. That's just what they did. I assume no responsibility for whether it "makes sense".
