Can anyone tell me how to determine engine type? I dont have code on oil fill tube. I have 68 cutlass 350 4bbl. Not sure if 4bbl was switched from a 2bbl originally. I know 2 bbl motor has less compression and hp than 4 bbl so I'd like to know what I have. Thanks.

 

There is no external way to tell the difference between a 9:1 and a 10¼:1 motor if the tag is gone and the manifold has been changed.

If you look at the pistons, the low compression has a deeper dish and a curved (U-shaped) notch at the front edge. The high compression has a shallow dish and a V-shaped notch.

- Eric

 

sadly, that is true.
The only sure way to know is to dismantle the engine.

Which might-as-wells you into....

 

Well, he could use one of those newfangled fiber optic cameras to look in through the spark plug hole. I've seen one at Home Despot that would fit in.

- Eric

 

Why do you suspect the engine was modified from 2bbl to 4bbl? If this is a Cutlass Supreme? The 68 CS used the 350 HC 10.25:1 as the standard engine. All the other models (except 442) had the 9.00:1 350 as the standard engine, but could be upgraded to the HC at extra cost.

This link may give you an idea of what the intake year is. http://wildaboutcarsonline.com/cgi-b...=9990322410657

You said it's a 4bbl. Is it a QJet? If it is it should have a number on the side somewhere. You can reference this to see whether it matches the cars production year.

Keep in mind, these things can all be changed and are not a positive way of knowing what the engine is. Are you sure the stampings on the oil fill tube aren't just painted over or covered with grime? If it was my car, I'd take out the tube and use some good cleaner/degreaser/paint stripper but NOT sandpaper to clean it. You may get lucky and find the engine number.

If nothing? Listen to Eric and Octania.

 

Allan R, I did find number on tube: 8305102. Also my tranny is a 2 speed jetaway. Is that any indication? Thanks.

 

What model Cutlass do you have? Is it the Cutlass S or Cutlass Supreme?

 

Allan R, I have a Cutlass S

 

That's just the part number for the tube itself...& both 2bbl & 4bbl 350s could have a JetAway.

Like Allan said, you might try to find the carb number. It should be a 7028250 for your car & maybe check the date stamp (4 characters) on the rear divers side base.

If they're correct, I'd think you have a high probability of having an orig 4bbl car.

If not, it just means a replacement carb may have been installed at some point...

 

The Cutlass S came with a 2bbl standard, and the 4bbl was the optional setup that year. So you could have a car that was ordered with the 4bbl option. Indy - great pics to show him what / where to look.

re: the filler tube. No that's not the filler tube number. The filler tube part number is Group 1.745 part number 400474. The stamping on the tube in 69 helps identify the motor. If it starts with 8 - that's a V8 6 = 6 cylinder. I'm not 100% sure how this works for decoding, but Kace what are the last 6 digits of your VIN?

 

Does the car have A/C? I have noticed that all the cars I looked at with A/C had the 4bbl HC engine. Not saying that is a definite, but if it does have A/C chances are it is a true 4bbl engine.

 

Thanks Indy68, My carb # is 702850 and date stamp looks like 2278. Allan R my last 6 digits of VIN are: 261505

 

Yes Jerseyjoe, I do have A/C.

 

Hey Jerseyjoe, is your 68 paint olds pewter? Mine is the same color.

 

Oops.

I always thought that number was just a part #. I never realized the tube had some sort of engine identifier (other than the paper 2 letter code label). Thanks Allan, for that correction.

Looks like the first digit of the fill tube # is the year (both Kace's & mine are '8'.....'69 would be '9' )and the rest may be the engine (not the car) serial/sequence number.

Although...if Kace's carb is original.... that date '2278' would by like Aug 14,1968 (227th day of '68) ...BUT his 8305102 is much lower than my 8485030 which is a April 30, 1968 built car (most of my date stamps are the 108-116 day-o-the-year range)...

So, in short, I have no idea what these numbers mean !!

But, if I had to gamble, it sounds like Kace has an original 4 bbl HC 350......

 

Hi, no, it is willow gold, white interior and top.

Sounds like you have the original 4bbl HC engine