Need help identifying

[hydroman6]

Digging thru a shed tonight and came across a block that confused me. 40 cu. (std bore) w/ extensive porting and welded in rickies has me thinking "alcohol". This motor only has two intake port covers, and the old brain is telling me that 40 cu. in. motors had four covers. I'm sure someone out there can set me straight......right?

[David_L6]

Some 40 cube motors had only two intake port covers. The Mark 35A is one that comes to mind.

[mac19f]

blocks

The Mark 35A, Merc 300 and the Mk55H-1 were 40 cu in blocks with two port covers. Also replacement 40 cu in blocks made after 1959 were two port cover blocks.

[crankbearing]

block number

Are there any block numbers on the side above the check valve just behind the crankcase split on the block side.

Regards,

[hydroman6]

Need help identifying

I remember the Merc 300 now that you mention it, but the 55H-1 is something I didn't know. It's always a good day when I learn something!

The block is stamped 808-1320 right behind the case split on #4 cyl., and has the S/N 1447053 stamped on top.

THX Again.

[sam]

In 61 there were also 40 ci 350's, but that serial number puts it in 1962 ... the year of the mysterious second run of Mk55H-1's

[crankbearing]

block number

Hey Sam,

I seem to recall finding a two port 55H block at Ron Tack's meet in may and it had the same numbers.

Regards,

[mac19f]

block numbers

The 808-1320 block was first used on the 35A.
The 55H-1 block was 808-1137.

[sam]

Hey Sam, I seem to recall finding a two port 55H block at Ron Tack's meet in may and it had the same numbers.

The second feature of a '62 Mk55H-1 is no model designation on the serial plate, just a serial number. I've never seen one in person and haven't asked what casting numbers are on the blocks. '62 Mk30H's are the same way --- but are the only factory 30H's with flat top cowls