Is it easy to tell the difference between a 302 and a 289

[Newsnake]

I am maneuvering through the California Registration process, I am going to what they call the bar exam for sb100 process. I have been told that if you do not have the actual engine type of the original car they can object to It being smog exempt. I know this is a dumb question but is it easy to tell the difference between a 302 and a 289 by looking under the hood?

[YerDugliness]

Originally Posted by Newsnake

I know this is a dumb question but is it easy to tell the difference between a 302 and a 289 by looking under the hood?

I wouldn't think that a dumb question...upon first view, they do look identical, with some minor differences.

What year 289 are you trying to get the BAR to believe you have? I ask b/c Ford first produced the 221/260/289 engines with 5 bolt holes where the bellhousing mounts, then sometime in late 1964 (or early 1965, there are differing reports) Ford switched the block to a 6 bolt mounting pattern for the 289.

Obviously, there will be other minor differences, too....but the BAR is quite skilled at finding out what year your 289/302 was built. They will look on the passenger's side of the block, behind the starter, for the casting "code" that tells them year, month, and day the block was cast.

If you MUST have a pre-emissions 289, I'd say get one of those with the 5 bolt pattern, at least for the SB100 process. Once you've gotten your SB100, there would be nothing to keep you from changing to the newer style 302, just beware that you'll have to change out the bellhousing, too.

The early 271 horsepower factory HiPo 289's are quite desirable, and fairly rare. If you can get one of those, you'll probably be just as happy as if you had a 302...or maybe more so. The cranks, in particular, are quite good, and IIRC they have 4 bolt mains rather than the 2 bolt mains the vast majority of 302's have (I think the 1971/1972 Cleveland headed Boss 302 blocks are 4 bolt, perhaps only on mains 2, 3 and 4...others will know much better than I do).

Cheers, and good luck, from Dugly

[PDUB]

It is fairly easy to tell... if you know what you are lookng for. As Dugly mentioned, they can tell quite a bit from the casting numbers: the date codes and engineering numbers. The engines are the same exact size externally.

The 6-bolt block began production in around July of '64 for the '65 model year. Prior to that, they were all 5-bolt blocks. If I remember correctly, the '68 model year was when the 302 went into production., though some of those blocks became 289 engines... they were using up older parts.

You have my number... call me and we can go over this in detail, if you want.

[FIA-ERA]

Plus, If the motor still has the original harmonic balancer it will give it away. The 289 had 3 bolt lower pulley while the 302 had 4 bolt lower pulley. If the block or heads have part# on them that will give it away too. The block should have a full casting part# above the starter looking up from under the car. If it's a 289 it should say C5AE or C4AE or at least start off with "C" as the dictates parts made in the sixties. If the block has "D", "E", etc that means it was made in the 70's then 80's etc. Other than that, as mentioned they are externally the same size. The Heads might have more "smog" holes and if it's a Mexican Block, it will have a good size casting "knob" on the front drivers side of the block. As mentioned, they converted over to 302's late 1967 and most 68 motors had 302 cast on them but some slipped out I'm sure. Regards, Matt

[jhv48]

Just tell them what it really is. These guys know their motors and will check the casting numbers.

It doesn't matter anyways, the SB100 is to smog exempt your car for life, so calling it something other than it is will accomplish nothing but telling the examiner that you don't know crap about engines or are trying to pull something over on him.

One other thing, assuming you have a carbed engine, make sure you have a closed breather cap system. You will be failed if you have a breather cap on your valve covers that vents anywhere other than the air cleaner. If yours vents to the air, buy one with a vent hose and attach the hose to your air cleaner assembly. It's a real pain to fail on this item and then have to make a return appointment.

[xlr8or]

Check the casting numbers. It doesn't matter which one it is, they just need to plug that information into the computer as the SB100 process allows you to choose whether the smog standards are applied based on the year of engine or the year that the car/body represents. In this case you can claim 1964 as the body type and smog to that level. The above comments regarding a closed PCV system are important. You won't pass without it.

[Mark IV]

Originally Posted by YerDugliness

The cranks, in particular, are quite good, and IIRC they have 4 bolt mains rather than the 2 bolt mains the vast majority of 302's have (I think the 1971/1972 Cleveland headed Boss 302 blocks are 4 bolt, perhaps only on mains 2, 3 and 4...others will know much better than I do).

Cheers, and good luck, from Dugly

The 289 production block were two bolt mains only. There were some "XE"
blocks with four bolt mains but none in a production car.

[Tom Kirkham]

302 did not convert over to 4 bolt harmonic balancers until 1970.
The 1969 Boss 302 balancer is almost identical to a 289 Hi Po unit.
289 blocks can easily be stroked to a 302.

[lovehamr]

Just a couple of points:
Any small block with a casting code of C8 or earlier can be a 289 and regardless of whatever else is in the casting # it could be a 302 as well. If you look to a few small block forums you'll see some specific instances.

The dividing year for 289/302 is 1968 and any small block car/truck that year could have either one as production was running through at least 7 assembly plants in the US for that year and they would use what they had on hand.

Aside from the Indy block, no 289s (that I'm aware of) were 4 bolt mains. The 289 HiPo s and the Mexican 302s made do with larger 2 bolt caps. Of the 302s only the tunnel port and Boss engines had 4 bolt mains on #2,3 and 4, #s 1 and 5 were like the HiPo caps.

On crank pullys; the 289s and 302s all the way through most of 1969 had 3 bolt mounting and in 1970 they switched to 4 bolt pullys.

Since I'm on the right coast I no nada about SB100 except that it's some kind of evil Kali thing to make car guys sweat bullets. In reality though any small block casting # of C8 or earlier should be counted as a 289.

Steve