Ok as some of you may know I am the kind of DUMB questions
. I always thought that if I saw a V8 and it was TPI'ed that it was a 350. Now Im learning that there are 305's that are TPI'ed???? If this is true? And if so is there any way to tell the difference between the two? Thanks..

 

I'm not sure how you could tell just by looking at the engine... but you can look at the RPO codes in the glove box/arm rest thing. A TPI 305 is RPO code "LB9". TPI 350 is "L98"

 

Look at the 8th digit on the vin# if its an "8" then the car has a 350TPI if it is an "F" its a 305TPI.

 

Silly me, I always seem to find the hard way to do things... what he said, vins r way easier =)

 

Hg~ Hate to remind you but we had this converstation once before...my sticker in the glove box/arm rest is "missing." As for the VIN it says its a 305 but according to the former ower they had the 305 pulled out and put a 350 in. I used to believe the former ower but now Im having serious doubts that the engine in there is a 350. For the sake of agruement if a 350 was swapped in there what else would have to be changed??? computer? wireing harness? ect ect...Is there that much difference in hp between a 305 and 350? Thanks for your help.

 

If i were you i would doubt the former owner too. This is one of the more common lies told by nasty liars when selling these cars. It's right up there w/ swapping in a vette engine (see, look at the TPI), yeah sure buddy, lol

As for telling what you have, stock you'd tell by the VIN as mentioned. As for what would have to be changed to run a 350, well, nothing 'has' to change, i could make a 350 run decently on the 305 chip and 305 injectors. In order to figure out what chip and injectors you had though (i mean, if they are changed then he probably swapped), you need to pull the ECM from under the dash to check the chip, and getting to the injcetors is a little more of a pain.
Other than that, you really would need to check the block for casting numbers. If it's still a alter model block, it will have the displacement in liters cast onto the back by the bellhousing flange on the driver's side behind the distributor. IIRC thats also where the block casting number would be located. If there's no displacement cast, you can look at the casting number and look it up at a site like www.nastyz28.com or www.mortec.com to see what block it is.

 

Sorry metalhead. I was told mine was a 350 when i bought it too(d@mn liars... plus i was young and didn't know any better). I'm all but 100% sure mine is a 305. BUT, there is this sticker under my hood that says 350 on it... I'll have to get a pic of it sometime...

 

Wernt we All ?

hahaha.

the casting numbers are the only way to know for sure, Other than pulling a head and measureing the bore.

 

Hey,

350 heads have an additional exhaust manifold bolt on the back bottom, which 305's don't have. (unless the real late heads do, I know the older ones don't)

The L98's if I remember correctly had markings behind the water pump on the block.

The L98 injectors are grey. The 305 injectors are black. Of course, you could have aftermarket injectors.

You could always pull the driver side valve cover, (gasket usually is reusable if its 88+ block) and tell me the numbers and I can tell you..

-- Joe

 

metalhead212121....I know how you feel. I am looking at a firebird with a good TPI motor to buy for 1000 bucks. The guy who owns it now says "its either a 350 or a strong 305." I asked for the casting numbers but he "doesnt have time to go check right now" I dont wanna pass up the motor because it will swap in easily and I can put my L03 in the body and sell it and make some of my money back. The HP difference can be alot or maybe not. I know some of the first 350's came putting out like 225 HP....some of the later 305's came stock putting out 230HP. On the other hand some of the later 350's are 245 HP motors and maybe more potential than a 305.

anesthes.....thanks for the info. I'm gonna go check that motor tomorrow. I might be contacting you as soon as I get the casting numbers to find out exactly what it is.

 

Sorry, just don't want to see this guy get confused.

 

The harmonic balancer on a 305 is thicker than a 350. The 350 is about 1 inch to 1 1/4 inches where as a 305 is about 13/4 to 2 inches. Im not sure about the actual inches but you get the point.

 

305 & 350 TPI balancers are the same, identical, no difference.

 

lol, thanks, i didn't want to be the one to keep raining on everybody's parade w/ their guessing game method of ID. Just read the casting numbers and you know what you have for sure.

but all balancers aren't exactly the same. GM did use different ones over the years. But it still holds that balancer doesn't mean squat since who knows what year the engine in question even is, or if it was the original balancer, etc.

 

If it's still a alter model block, it will have the displacement in liters cast onto the back by the bellhousing flange on the driver's side behind the distributor.

Should I be looking up top or from the bottom to see the casting #'s?? Im assumming I should be looking from up top. I tried looking from the top but theres too much #$@^ in the way for me to see anything.

As for the comment from Ed Mahar about getting me confused...its too late Im already confused. :lala: :lala: :lala:

Later

 

Ed,

THe bolt I'm talking about is the exhaust manifold. The 350's had an additional bolt in the back.

You really can't get away with putting 305 heads on a 350. The compression ratio would be insane. And if they even moderately set the timing, and didn't compensate for more fuel it would have blown up by now.

I've stripped a ton of these cars (I sell used parts on ebay) and all the 350's had grey injectors, all the 305's were black.. ??

I can't remember the exact marking. I forgot to look today when I was at the shop. my GM service manuals (from when my family owned a dealership) explains how to ID them using this marking. It most likely applies to only newer blocks.

-- Joe

 

There are only 2 ways to tell what you have. Pull a head and
measure the bore or look behind the drivers head at the bell
housing flange like Ed said.

And the ballancer idea, all 305 and 350 TPI engines use the same.

 

I wasnt sure about the TPI motors, but check the earlier models of the 305 and 350 and see if what I am saying is right. Trust me on the older models the 305 is thicker.

 

metalhead212121,

I know Ed Maher posted a link to www.mortec.com earlier. If you haven't gone there, they have a lot of descriptions including pictures of where to find all of the different markings possible. It is an excellent source to find out the meaning of anything you find as well.

To directly answer your question about where to look from...
Look from the top. There is a lot of stuff there, I know. Maybe you can't see it with everything in a TPI engine compartment. I've actually never tried to find the casting number in a stock engine bay. Good luck.

MikeS

 

People usually don't swap in a completely stock older engine. A lot of hack shops would have no problem throwing a 305 balancer on a 350 and vv, since they basically interchange. You just never know what you're going to get. 400 balancer, sure that unique. 305 or 350, well you can tell if it's a ZZ4 crate anyway

 

305's and 350's did interchange ballancers through the years
but there were 305 only balancers and 350 only balancers
depending on application.