Coolest racing engine of all time???

**Ron Hill** · 09-25-2011

Originally Posted by 194265

My answer was for Mark 55's not Mark 55H's.

I know that some Mark 50's were sand cast, but I never knew there was and never saw a Mark 55 that had a sand cast block.

When we legalized the Mark 55 blocks to run on Mark 55-H's, no one ever talked about sand cast blocks. We went back to 860000 serial numbers but the best 55 blocks were black with the serial number 89 something. They came off Mark 55 E and were high compression, but still within the 55-H specs.

I would have loved to have been allowed to run a Mark 40 block with the big carbs....in APBA D Stock.

**Gene East** · 09-26-2011

I thought ALL MK 50's were sand cast and I've never seen a sand cast MK 55.

That doesn't mean they didn't exist, but one would think any left over sand cast blocks would have been used up as "Wizards".

Maybe not. On second thought, weren't the 4 cylinder "Wizards" MK 30's?

In any case, the sand cast blocks were much easier to repair. They welded like spreading butter.

Interesting that MK 55 blocks had to be approved as replacements for MK 55H's.

I understand "Wizard" powerheads were not legal in stock. True or false??

Too many rules in stock!

**John Schubert T*A*R*T** · 09-26-2011

Originally Posted by Gene East

I thought ALL MK 50's were sand cast and I've never seen a sand cast MK 55.

That doesn't mean they didn't exist, but one would think any left over sand cast blocks would have been used up as "Wizards".

Maybe not. On second thought, weren't the 4 cylinder "Wizards" MK 30's?

In any case, the sand cast blocks were much easier to repair. They welded like spreading butter.

Interesting that MK 55 blocks had to be approved as replacements for MK 55H's.

I understand "Wizard" powerheads were not legal in stock. True or false??

Too many rules in stock!

Gene,

Wizard blocks were legal to be used on MK30H's in stock, and preferred by many. There was a myth that ther had the padded blocks, some may have but not all. Merc allowed several padded 30 c.i. blocks to get out & never petitioned the SORC to dias-allow them. THose that had them were virtually unbeatable.

**194265** · 09-26-2011

My article on the Sandcast Thunderbolts was published in the Antique Outboarder Book dated April, 1990 and was reprinted here 7/26/2010 titled The Sandcast Thunderbolts. Take some time guys and read it. All Mark 50's were Sandcast and 1955 Mark 55' S/N's 831021 - 832999 were Sandcast blocks.

**Ron Hill** · 09-26-2011

Where is this article about the Mark 50's and Mark 55's....???

In the fall OF 1976, I SPENT A WEEK DRIVING FROM YUMA TO LAS VEGAS. I was looking form 89 serial numbers on Mark 55-E's. Seems I had my wife's Monte Carlos loaded with powerheads....All 89 serial numbers...I remember seeing 83 numbers and wondered why I needed the 89's.

Charlie Strang told me that the 89's were 55 E's and had higher compression. I never saw an 83 that was sand cast...

Gene,

As far as I know, the Wizard blocks all measured the exact same as the Mark 30 and the Mark 30-H was the exact same as the MARK 30. There were rumors that some Wizards had some blocks that had "padded" heads. My dad spent a lot of time in Iowa, Nebraska, N and south Dakota looking for 30 blocks as finding fresh water blaock in California were few and far between.

We ended up with three good Mark 30's. One was a Mercury block from Nebraska, we called that the Nebraska motor, one was a Wizard......The Wizard had no markings on the block where usually the four cylinder motors said, "Turbo Four"....just a smooth blank block. My third good 30-H was a black block from an original Mark 30-H....

My fears about the "PADDED" Wizard block came as a way to keep people like my dad from saying "BULL ****". At one time we had maybe 22 Mark 30 blocks. I had my dad measure the intake and exhaust posts on everyone, I wrote the numbers down and sometime switched block on him to double check his numbers. The damn blocks were so close you could say they were the same.

About this time, there were a couple of young races from NorCal that started running very fast in C Stock Hydro. I did their props, so I knew hat pitch they could trun and they won several Nationals, so I liked them....They claimed to run Wizard blocks. My dad decided to find some Wizards for us.....We found several, no "PADDED" ones......

About 12 years ago, I was talking to Lon Stevens and he was telling me how he welded heads in Mark 30 blocks, and mill Turbo Four off the side...He said, "His 30's CC's 14.2....." Most 30's as I recall were closer to 21 CC's...

**Mad Cat** · 09-26-2011

I was honored to ride deck for Wayne at Lawrence Lake 83 or 84 nationals ! That boat must have been 15' long and rode like a Caddilac ! My ears rang for a week after !
John Biagio

**JohnsonM50** · 09-26-2011

Originally Posted by Jengle37

I know this is a mostly outboard website, but being an inboard fanatic I'd have to say the Merlin is the coolest racing engine of all time by a long shot, followed by the V12 Jag that was in Mitch Lemke's ET79.

The Merlin powered some wild aircraft, the Spitfires, Mosquito's [fastest plane on earth in it's time] & the P51 Mustangs. If not for these great engines the Luftwaffe might have prevailed.