I bought my '88 about 2 months ago and i'm having trouble telling if it's a 350 or 305, i've been told by most that it's a 350. It's got a Holley 4160, Weiand Stealth intake manifold, and a turbo 350. It also pulls to 7000rpm, I thought the tach was just wrong, but it idles and cruises correctly. Another thing I find strange is the center bolt valve covers, and the older 3 wire HEI which tells me it isn't an '88 motor. I know how to get the cast number and where it's at, but we all know you need to be a contortionist to get it while the motor is in the car. Any suggestions would be helpful.

Here is a pic of the motor if it helps, but it's not really that detailed.

 

The only way to be sure is to check the casting number.

 

I was afraid of that, well the motor in this is probably coming out, my uncle is selling me a 355, and this motor is probably going into an '85 RX-7.

 

Since all the SBC look the same externally, there's isn't much to help you tell if it's a 305 or 350. The casting number can say if it's a 4" bore block or not. You can't pass off a 305 for a 350 if the casting isn't for a 4" bore block.

Try looking for the suffix codes. They'll be stamped on a pad at the front of the passenger side head. It'll be down in behind you AC compressor. The suffix code can tell you what the engine was originally out of. If the block has been decked, the suffix code will have been machined off.

Depending on the age of the block, it may have 5.0L or 5.7L cast in the side of it.

 

Probably just an old L03 305. Get a real tach on there though, I doubt you are seeing over 5,500 rpm.

 

Either get a little mirror and a flashlight and find the casting numbers, or pull a head and get a ruler.

 

This is a 305 that had a pair of 350 heads and 350 head gaskets on it. Notice the difference.

 

Thanks, I will probably have to remove the A/C to see it, but it's better than removing the motor.


As for the mirror, lol I attempted it, and also tried the foil trick and couldn't find much since most of the original wiring is in the car, and blocking my view.