hi
I was wondering if anyone had an idea on how to tell what era an engine comes from. I have a 1971 f100 that came with a 240 six it now has a 302 v8. the problem I have is when I ask for parts the folks ask for the year model. and now I have been told that in 1976 is when they made changes to the motor so how can I tell if it is pre 76 or post 76? any points would be much appreciated.
thanks


sam

 

Are you talking about significant change in a 302? I thought the big change was in 1979 with the 5.0. The balance between the older 302 and the 5.0 (yes its a 302) changed significantly, as did the water pump flow. The older motors have a 28oz external counter balance on the flywheel/flexplate, the newer have a 50oz counterbalance. The newer motors have a reversed flow water pump. What kind of motor parts are you concerned about?

Drives me up the wall when counter people quiz me on year and engine ect for stuff I know is completely irrelevant. I know its the way it works, but most of the time for my needs it just makes me shake my head.

As I understand it, the rebirth of the V8 into Mustang IIs began in the initial year with a 255 Windsor. This motor had a smaller bore than the 289/302. I think the 5.0 was a re-design for the new Fox body Mustangs (and all the other cars and light trucks that would use a small V8)

 

thanks for the reply Old Brown Truck


I am trying to find a exhaust manifold left hand side dual exhaust. looks like the major difference is where the exhaust connects to the pipe. the dual has an angle towards the rear and the single comes straight down more or less. any other difference I should look for?

 

decoding the casting # on the block can give you a ballpark

 

I don't think the difference is single or dual exhaust. It would be depending on the chassis Ford put it in. They would have to route the exhaust pipe around crossmembers,inner fenders,firewalls,etc. That would designate where the manifold pointed.

 

Casting and date code will be located on the block above where the starter mounts. You'll have to pull the starter to read the casting.

The major changes to the 302/5.0L engine came in 1981.

Prior to '81, there'll be a threaded hole at the left, rear corner of the block for a mechanical clutch linkage pivot to screw into, for a manual transmission. From '81-2001, there will not be a threaded hole there.

In '81, the front and rear main seals went to a one piece design from the older two piece design.

The '81-2001 front cover will have a crank seal that installs from the front of the engine. '80 and earlier will require removal of the front cover to replace the seal. --there are various different front cover designs. Some have a hole for the dipstick, some don't. Some have a hole for a mechanical fuel pump, some don't. Some have a provision for mounting a crank trigger sensor (Explorer with EDIS-8 Distributorless ignition system).

'81-2001 will have a 50 oz reciprocating assembly imbalance. '80 and earlier will have 28 oz imbalance.

First H.O. (High Output) 5.0L engine was put in the '85 Mustangs. This was the first use of a 5.0L roller cam engine and also the last year for a carbureted 5.0L (302) engine.

All 302s and non-H.O. 5.0L engines have a 1-5-4-2-6-3-7-8 firing order. The H.O. 5.0L engines have the same (improved) firing order as the 351W/5.8L engines; 1-3-7-2-6-5-4-8.

5.0L engines that came with a serpentine belt have reverse direction (flow) water pumps.

'68/'69 water pump outlet exits to the right. '70-2001 exits to the left.

(At least on the cars) Harmonic balancer and pulley will have 3 bolt holes on '68/'69 model 302s. '70-95 cars will have 4 bolt harmonic balancer/pulley.

Explorer 5.0L engines, without a distributor, will have 3 bolt harmonic balancers and the serpentine pulley is cast integral to the balancer.

 

Beings OP picked the year 1976 I think he might be referencing the drop in compression ratio and rise in emission parts.

 

That's good info ultra. There are a couple anomalys worth mentioning. Some of those changes like the one piece rear seal did come mid year on 81 and there were also common non HO 302s with the HO firing order. For instance certain cars with California emissions.

 

Look down by the starter for the engineering number and date stamp in the block. It'll start with a letter, then a number, and then two letters, followed by a bunch of other random bits.

On my inline six, the number is C6AE-6015-D, and then two inches over you can see an 8L7.

The first letter is the decade in which the casting was designed.

B = 1950s
C = 1960s
D = 1970s
E = 1980s
F = 1990s

The number is the year in which the casting was designed.

With mine being C6, the casting was designed in 1966. That does not, however, mean that the block was cast in 1966. That's what the 8L7 date stamp is for.

The first number is the year of the decade in which the block was cast, and being a C6 block we can assume it was in the 1960s. Therefore, an 8 would indicate 1968.

The letter is the month in which it was cast, from A-M, omitting the letter I. Each letter indicates the month in numerical order. The letter L would therefore represent November.

The last number is the day of the month in which the block was cast.

From this, we can conclude that my block was cast on November 7, 1968.

 

I don't know that the factory would have put out dual exhaust on a 302. It's not difficult to have an exhaust shop create dual exhaust. I did have Car manifolds on a 302 I put into a 76 F100. I ended finding a truck exhaust manifold for the passenger side because it aimed down at a 45 degree angle instead of straight back.

I'd say find any small block (windsor) exhaust manifold from a pickup truck.

 

gentlemen I thank you very much for the information. I have gained a lot from this website. I have been tinkering with these old trucks since they were new but never needed a lot of this info. back in the day you just took the old part to the parts house and said I need this. now the kids working there look at you like you stole their lolly pop.


thanks again


sam

 

302 heads through '76 ('68-'76) had 58.2cc chambers. --one exception is the J-code '68 Mustang 302 4V heads. They had 53.5cc chambers.

Decent 302 head casting numbers are: D0OE-B, D1TZ-A, D5OE-GA, D5OE-GA and D5OE-A3B. The D5OE heads were the first to be fitted for Thermactor through the ends of the casting instead of over each exhaust port. This eliminated the external air manifold. The hole can simply be plugged if not running the emissions plumbing and air pump.

'77 is when things really started going down hill for the 302 heads. '77-'84 heads increased to 69cc combustion chambers, which lowered the compression, and performance, significantly.

It's pretty easy to spot the non-desirable 302 (and 351W) stock iron heads just by looking at the spark plugs. If the heads have 18mm plugs (requires a 13/16" socket to remove/install plugs), they are the better heads. If the spark plugs are 14mm (5/8" socket), they are the less desirable version.

Non-desirable 302 head castings are: D7OE-DA and D8OE-AB.


The best flowing factory iron heads come from the 5.0L Explorers. Prior to 1997-1/2, the heads used were the GT40 (3 bar) heads from the 1993 Cobra Mustangs --minus the performance valve springs and factory roller rockers that were on the '93 Cobras.

From 1997-1/2 - 2001, there was another improvement in the 5.0L iron heads. This version was the GT40P (4 bar) heads. These heads outflow and out perform both the old 289 HiPo heads and the early 351W heads.

 

No Ford trucks came with dual exhausts until the Lightning's of the late 90's.

btw: Mustang II: 1974/78 - available with 2.3L OHC 4; 2.8L V6 & 302 (1975/78).

Fox body Mustang introduced in 1979, 255 (4.2L) introduced in 1980.