How do you tell a 55 from a 56 308?

[Deleted User]

Just by looking at the outside of a 308 engine, what are the distinguishing features that would tell you if it is a 1955 or 1956?

dougson

If the head is still on the engine there should be a date stamp, numerals indicating day, month, year. The prefix letters on the block are the same but the sequence of numbers is different, you can find them somewhere on this website, I don't have info in front of me. To be certain remove one of the valve covers, if possible, and see if the lifters are solid (adjusting screw present) or hydraulic, '56 was only year for hydraulic lifters.

[Deleted User]

Are there any external features that distinguish them?

dave s

Identification of 308 motors: > Serial number on 51-54 is vertical on top front right side of motor and 55/56 is on boss on left. side of motor below head.

> Serial number starting with F1001 is 1955 and starting with F8601 is 1956. Early 1955 had solid lifters and late 1955 & 1956 had hydraulic lifters.

dougson

> Serial number starting with F1001 is 1955 and starting with F8601 is 1956. Early 1955 had solid lifters and late 1955 & 1956 had hydraulic lifters.[/QUOTE]



Very late '55 for the hydraulic lifters, the '56 parts book lists hydaulic lifters as a '56 part number only.

50C8DAN

I have always thought it ironic that AMC decided to incorporate hydraulic lifters for the last year of the 308. I wonder what prompted this? I am not sure how the sales numbers break down but I can't imagine that there were many 308 powered Hashes sold in '56, my guess most were V8s. Why would they put the time and effort into releasing a one year only change?

[Deleted User]

I've been told that was because valve adjustment in a 55 Hornet is a real challenge. The AMC body has the engine compartment too narrow. It's also the reason the Twin H intake manifold is different for those cars.

[Deleted User]

50C8DAN wrote:

I have always thought it ironic that AMC decided to incorporate hydraulic lifters for the last year of the 308. I wonder what prompted this? I am not sure how the sales numbers break down but I can't imagine that there were many 308 powered Hashes sold in '56, my guess most were V8s. Why would they put the time and effort into releasing a one year only change?

Actually there were quite a few '56 6 cylinder HASH cars. Many of the cars I have found over the years are 6s. In 1956 the AMC buyer was usually looking for a lower priced car and the V8 would have been considered an unneccessary added cost.

dougson

Access to the engine was severely limited in the Hash cars and the switch to hydraulic lifters solved the problem. Also, the '56 engine came with the 309742 flat top cam, a cam that supposedly caused a lot of problems when introduced in '54 and later replaced. Why Hash cars went back to it I don't know but maybe the hydraulic lifters made it more acceptable (less noisy). The '55 - '56 engines had the highest hp rating in stock form (175 with twin-H).

PAULARGETYPE

I am not sure how the sales numbers break down but i can't imagine that there were many 308 powered hashes sold in '56, my guess most were v8s. Why would they put the time and effort into releasing a one year only change]



Dan

3380 56 hornet '6'

358 hollywoods

3022 4 DOOR SEDANS



85 STANDARD

368 OVERDRIVE

2927 HYDROMATIC



2519 WERE WASP 202 6 CYL

ALL SEDAN SO 25% WERE SMALL CARS



1757 HORNET SPECAL

229 HOLLYWOODS

1528 4 DOOR SEDAN



3015 V8 PACKARD 352

1053 HOLLYWOOD

1962 4 DOOR SEDANS

[Deleted User]

royer wrote:

I've been told that was because valve adjustment in a 55 Hornet is a real challenge. The AMC body has the engine compartment too narrow. It's also the reason the Twin H intake manifold is different for those cars.

You are correct by saying valve adjustment on 55's. You had to disconnect the exhaust front pipe, remove upper and lower radiator hoses along with heater hoses. Shift linkage and throttle linkage, gas line to the fuel pump and all wiring. The car had to be on a lift, raise car 5 feet, put a transmission jack under the engine, remove all bolts that hold the cross members on, then lower engine with transmission, drive shaft tube and the rear turns just enough so engine is down to see valve covers. What a pain to adjust the valves in the rear cover with the new intake and exhaust manifold. I know as I sold and serviced them. 56 was nice but those hydraulics started to make noise after 25,000 miles and they were replaced with solid lifters and the old 306344 cam under warranty. That was a job. Walt.

[Deleted User]

I have some notes on 55-56 engines that I took a while back from other Hudson members that said the water drain plug is more toward the center than the back of the engine and the dip stick is also more toward the middle of the engine and the carb tube is a casting. These were external features that you could see.

I believe that I have heard the block casting around the bottom of the engine is different, but not sure where.

Unknown

Just under the dist. trere are is a casting letter A thrue L. Then numbers' I tore a engind down last year that this casting was L95. Ken U told me this engine was cast Dec 9 5. Itdid not have hyd lifters but had cam 309742 and was sett ing ina 54 hornet. Who nows what has been done to the cars in the pass 50 years. The yoke of the Hash hydro had been sawed off with a hack saw pure junk.

[Deleted User]

Billy K.TN. wrote:

Just under the dist. trere are is a casting letter A thrue L. Then numbers' I tore a engind down last year that this casting was L95. Ken U told me this engine was cast Dec 9 5. Itdid not have hyd lifters but had cam 309742 and was sett ing ina 54 hornet. Who nows what has been done to the cars in the pass 50 years. The yoke of the Hash hydro had been sawed off with a hack saw pure junk.

The oil pan has the big part in the front and narrow to the rear. Can not use this pan in 51 to 54. Also the crank is 1/2 inch shorter and uses a neoprene seal. To use this engine in a 51 to 54 just use the 51 to 54 crank and the neoprene rear main seal. To use the engine as is, just add the 1/2 inch crank spacer. Walt.