The Ford Barn

Racermart · 11-09-2013, 11:10 PM

I found a pair of mercury heads my question is what advantage would i have if i ran them on my ford 8ba engine? not sure if it matters for power preformance or just looks?

mtflat · 11-09-2013, 11:39 PM

There is no advantage - in fact it will go the other way and have less compression. Unless you're running a blower keep them off your Ford.

40 Deluxe · 11-09-2013, 11:42 PM

It matters! Power and performance will go down! The Mercury heads will give much less compression, which will degrade performance and mileage.
Ford wanted the same compression for both Ford 239 engines and 255 Merc engines so they made the combustion chambers bigger in the Merc heads. Back in the day, a cheap hop-up trick was to put Ford 8BA heads on a Merc engine for better performance

itsa52 · 11-10-2013, 08:17 AM

So on a Merc engine how much extra CR do you get by putting Fords on?

mtflat · 11-10-2013, 09:36 AM

Just to be clear, it's only on the late series Merc with a 4" stroke. Next, it depends on which ford heads. 8RT or 8BA - very little or nothing.

What you want are 52/53 EAB heads on the merc. CR bumps up about 1.5 (or so I saw in a chart)

woodypecker · 11-10-2013, 09:41 AM

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I put Mercury heads on a blown 8ba to lower compression. Everyone who looks at it insists I have a Mercury enen when I tell them differently.

rotorwrench · 11-10-2013, 11:23 AM

FoMoCo always used a larger chamber when they either increased stroke or used a particular engine for trucks or heavy car applications. This started to change in 1952 due to better quality fuels available but it sort of missed the flathead era. The EAC heads still have a larger cc chamber than the EAB. The Merc heads are comparable to the 8RT heads but there is a difference that was enough to make them a different part number but it may have also had something to do with name branding. Ford went to the overhead valve inline 6 in 52 plus the 279 & 317 Y blocks for Lincolns & big trucks so less and less L-Head V8s were being produced.

11-09-2013, 11:10 PM	#1
Racermart Member Join Date: Jul 2010 Location: East Aurora NY Posts: 31	mercury flathead head ? I found a pair of mercury heads my question is what advantage would i have if i ran them on my ford 8ba engine? not sure if it matters for power preformance or just looks?

11-09-2013, 11:39 PM	#2
mtflat Senior Member Join Date: May 2010 Location: Kalispell Montana Posts: 344	Re: mercury flathead head ? There is no advantage - in fact it will go the other way and have less compression. Unless you're running a blower keep them off your Ford.

11-09-2013, 11:42 PM	#3
40 Deluxe Senior Member Join Date: May 2010 Location: now Kuna, Idaho Posts: 3,779	Re: mercury flathead head ? It matters! Power and performance will go down! The Mercury heads will give much less compression, which will degrade performance and mileage. Ford wanted the same compression for both Ford 239 engines and 255 Merc engines so they made the combustion chambers bigger in the Merc heads. Back in the day, a cheap hop-up trick was to put Ford 8BA heads on a Merc engine for better performance

11-10-2013, 08:17 AM	#4
itsa52 Senior Member Join Date: Aug 2012 Location: Nebraska Posts: 603	Re: mercury flathead head ? So on a Merc engine how much extra CR do you get by putting Fords on?

11-10-2013, 09:36 AM	#5
mtflat Senior Member Join Date: May 2010 Location: Kalispell Montana Posts: 344	Re: mercury flathead head ? Just to be clear, it's only on the late series Merc with a 4" stroke. Next, it depends on which ford heads. 8RT or 8BA - very little or nothing. What you want are 52/53 EAB heads on the merc. CR bumps up about 1.5 (or so I saw in a chart)

11-10-2013, 09:41 AM	#6
woodypecker Senior Member Join Date: Jun 2012 Location: Clarkston, Michigan Posts: 239	Re: mercury flathead head ? Sponsored Links (Register now to hide all advertisements) I put Mercury heads on a blown 8ba to lower compression. Everyone who looks at it insists I have a Mercury enen when I tell them differently.

11-10-2013, 11:23 AM	#7
rotorwrench Senior Member Join Date: Jun 2010 Location: San Antonio, Texas Posts: 16,436	Re: mercury flathead head ? FoMoCo always used a larger chamber when they either increased stroke or used a particular engine for trucks or heavy car applications. This started to change in 1952 due to better quality fuels available but it sort of missed the flathead era. The EAC heads still have a larger cc chamber than the EAB. The Merc heads are comparable to the 8RT heads but there is a difference that was enough to make them a different part number but it may have also had something to do with name branding. Ford went to the overhead valve inline 6 in 52 plus the 279 & 317 Y blocks for Lincolns & big trucks so less and less L-Head V8s were being produced.