Mark IV Block Question: How big can I go???
 

Hello everyone.... I have two boats... 1988 and 1987 Donzi Z-33's and am planing on rebuilding the stock Mark IV blocks in at least one of the boats.

Do you know how much I can boar this thing out without getting into trouble?? Also, will a 4.25 crank just drop in or will there be machine work involved??

Not trying to drop a whole lot of cash here on new blocks...

Your thoughts are appreciated...

Q

Re: Mark IV Block Question: How big can I go???
 

you can bore out to .060, I would only go to .030 if the cylinders clean. But before I spent a lot of money I would look in to a 425hp HO 454 crate motor. I can get you pricing. I put two of them in my 29 fountain and they are running strong. Do you have any pics of the 33 Donzi. I had a 1976 Donzi sweet 16 with a 350 motor one nice boat.

Re: Mark IV Block Question: How big can I go???
 

here is a picture of my boat... it is the 1988 I had planed on selling it for 15K and had a lot of people looking... but no cash on hand.

Shoot me the price of the HO motor... and we can go from there.

Also, Do you know if a Mark IV will take a 4.25 crank?

Thanks!

Q

http://i9.ebayimg.com/02/i/03/fa/59/05_12_sb.JPG

Re: Mark IV Block Question: How big can I go???
 

It will take a 4.25 stroke crank. You will need machine work on the block for clearance. You also will need new rods and pistons. If you buy a cheap crank you most likely will need addition machine work. :eek: Been there done that. Good advise on the crate motor. You will end up spending that much money on a rebuilt.

Re: Mark IV Block Question: How big can I go???
 

Forgot to ask, boat looks nice. Is that a single or twin?
15k sounds like a good price for that boat :D
What state?
JIM

Re: Mark IV Block Question: How big can I go???
 

Hey Jim... yes, pretty aggresive price. The interior needs to be redone and the boat needs power/drives.

I am located in South Carolina... If you'd like more pictures please let me know....

thanks!

Q

Re: Mark IV Block Question: How big can I go???
 

what drives are on the boat now?

Re: Mark IV Block Question: How big can I go???
 

There are no drives on the boat now... but I do have a complete set of Blackhawk drives... they are posted in the for sale page.

Re: Mark IV Block Question: How big can I go???
 

I put a 454-425 HO crate motor in my Donzi Criterion, and I gotta say it's the only way to go. GREAT engine for the money.

JH