The '53 truck that I bought apparently has a replacement engine. The previous owner told me it was a Mercury 302 V8. It is certainly a V8 and a Mercury, but how do I tell the displacement? My concern is that the 53 Ford truck shop manual (on CD) that I just got doesn't cover the Mercury 302 V8.

Where can I get correct data about this engine?

-Scott

 

We're going to need quite a bit more information. The only 302 V-8 Ford made is the good old small block that we all know and love. It went into everything - Fords, Mercs, Lincolns, trucks. There wasn't a Mercury specific iteration. The production run ran from '68-current, so no, your CD shop manual isn't going to cover it if that is what you've got. You say it is certainly a Mercury - why do you say that? Are there some kind of identifying markings? What do the valve covers look like? Describe them in detail - especially the number of bolts and whether they are right through the middle or around the edges. Where is the distributor located? Answer these questions and we should be able to at least narrow it down. A picture would be even better.

 

I'd be glad to send or post pics,- how do you put up a gallery here?

-Scott

 

I think there was a 302 that was used in the '50s in the cars. George mentioned something like that a long time ago in one of his posts. George could clear up the matter.

 

It looks like the V8 238 ci. shown in the manual. Maybe the guy was shining me about the Mercury 302 part. He said that the engine alone was probably worth the price of the truck.

-Scott

 

If my memory serves me correctly, Ford had the 292 and the 312 V-8's in the late 50's, not the 302.

 

Ford never had a 302 in a car before the SBF of the 60's. There was a 302 truck motor used in the 56-63 F700 and bigger.

Never was a 238 either so try and get the story straight or check your typing.

The 239 flathead was used 1946 up thru 53 in the US, 54 in Canada. The Merc 255 is the same engine with a different stroke and was often swapped in.
In 54 the 239 OHV came out in the US Ford car and light truck, the 256 & 272 in 55.

Trucks up thru the F600 used the same motor that was available in cars, above that they (generally) used versions of the Lincoln or a truck specific design.

Hope that helps resolve some of the confusion.

 

While putting in some antifreeze and changing the oil last night, I noticed that the engine (which looks like the 239 c.i. engine in the manual) clearly has Mercury cast into the blue flathead cylinder heads. ??

-Scott

 

Hi

The 239 OHV was used in the ford and the 256 OHV was used in the mercury in 1954. Here in the states

Chuck

 

This is clearly a flathead motor, though. It has Mercury cast into the heads.???

-Scott

 

The Ford and Merc Flatheads can be thought of as "Cross Dressers" the parts interchange, as long as you keep the rotating assemblys matched. The Heads can be marked any number of ways - 8BA - 8RT - 8CM - EAB - EAC.
The Fords used a 3bolt flange on the carbs, the Merc a 4bolt flange with a carb that resembled a Teapot.
Truck engines used a short bolt-on bellhousing (See my gallery)

 

Ok you win it's a flathead with at least Merc heads.

My comment was referring to the introduction in the states of the 256 cu in OHV (Over Head Valve) engine in the 1954 Mercury.

Chuck

 

Merc headed flathead engines were used in Canadian trucks. What is the casting ID on the heads?
For instance, US 53 Merc car heads would be EAC and Canadian CEAC.

OTOH, putting US Merc heads on a standard 239 will reduce the CR. This may have been done to reduce pinging on cheap gas.
Or as mentioned anything could have been swapped in over the years.

 

Hey Carl! So it obviously stands to reason that if one were to put Ford heads on a Merc, the compression ratio would go up. Is this a common thing to bump the horsepower or is it even enough to mess around with? Just curious.

 

Corretomundo 'rage.

A common swap was to put EAB heads on anything in the 8BA style block as those were the last and best of the factory ones. Replacing 8CM or 8RT, which had the largest chambers of ~ 83 cc with ~70 cc EAB's gives a very noticable boost.

I build many engines with .050 shaved EAB's. The true cr is up in the 8's ( stroke and bore need to be factored in) and the transfer area is big enough to be efficient. There is also enough head room for up to a .365 lift cam without flycutting.

And the best thing is that you can really torque them down and not have a dissimilar metal and thermal expansion differential problem as with aluminum.

One note: Stock and many aftermarket heads have poor production chamber volume control. I always cc and then bring them all to within 1/2 cc or so. Ive found up to a 3 cc difference out of the box.

Being that picky isnt necessary on a stocker but when it is a fairly hot build then you dont need unequal chamber problems.