mercury ? cam

[Lawrie]

I have what I think from my books may be a mercury 8ba style cam,
I had machined the front off to allow me to use it in my 36 lb engine,( it was in there for a while ,but I can't remember how it went) it has 320 lift,and I thought it may have been reground as it had a base circle of 1.121 against the stock early cams I have of 1.165.
BUT after having another look I see that if you want more than the .300 lift of the stock cam,you can't get that without having the smaller base circle diameter as the tip of the lobe will not fit through the cam bearings.so it may NOT have been reground and be a standard ford or mercury cam
Would any one have a 8ba style mercury cam they could measure the base circle for me, so I can positively ID it.
Thanks Lawrie

[51 MERC-CT]

An as removed cam from a 77K 1950 Mercury measures ( 1.112 ±)

[GOSFAST]

Originally Posted by Lawrie

I have what I think from my books may be a mercury 8ba style cam,
I had machined the front off to allow me to use it in my 36 lb engine,( it was in there for a while ,but I can't remember how it went) it has 320 lift,and I thought it may have been reground as it had a base circle of 1.121 against the stock early cams I have of 1.165.
BUT after having another look I see that if you want more than the .300 lift of the stock cam,you can't get that without having the smaller base circle diameter as the tip of the lobe will not fit through the cam bearings.so it may NOT have been reground and be a standard ford or mercury cam
Would any one have a 8ba style mercury cam they could measure the base circle for me, so I can positively ID it.
Thanks Lawrie

Hi Lawrie, have an old 8BA style blank on the shelf here with the same specs, 1.120" (nominal) base and .330" (nominal) lift.

It has a "C41" cast into it and doesn't appear to be a reground piece. The distance between the journals and the heels of the lobes measures .340". This measurement should help to determine whether or not the base has been "shrunk"??

Thanks, Gary in N.Y.

P.S. With respect to the amount of power you will see/feel from a .300" lift to a .320" lift (all nominal) or thereabouts may not even be measurable?? The duration numbers (mainly at .050") are much more "critical" to overall performance/fit than the net lifts. We've see this while dynoing the SBC platform when going from 1.5:1 to 1.6" rockers, net lift gain .030", but really can't see/measure it in the numbers?

[rotorwrench]

I don't know if all FoMoCo USA made 49 thru mid 51 cams have it but most have an 8CM casting mark. The 1CM replaced it after the newer rotator valve system was introduced and it is marked in similar fashion. Some folks like the EAB cams since they have a bit better grind than the Merc types when stock but I don't know if they are any better than any other for grinding new profiles.

[Lawrie]

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Thanks for the info,folks,I just had a closer look at the 8ba cam and it has 8-a cast in,I can't make out what it is between the 8 and the a,
Checking the dimension that Gary measured it is .340.
So maybe this cam would be better in a larger(265) engine than a 221 .
Thanks
Lawrie