e8411a

I need to locate a block for a rebuild. The one I have is scrap and since I am running twins I don't want to mix the set. A friend of mine told me that World and Dart make a copy of the Bowtie but I don't know the part #. Any advice?

Reed Jensen

World markets their's under the name "merlin". Check any hypo parts house. My engine machinist prefers Dart over Merlin. That's his choice. I'm assuming you are looking for tall deck Mk IV's. You can call Dave at Burbank Speed and Machine. He will know where to order one or can order it for you.(818) 846-8310

e8411a

Thanks Reed,

I am actually looking for a 9.8" deck. I am not sure if that is considered tall or not.

Reed Jensen

That's a standard height block. Tall blocks are 10.2".

rmbuilder

e8411a,
Chances are you will not find a new 10051107 Bowtie block. If you want to match blocks and components, GM does make (3) Bowtie blocks that will work with your 9.8" deck, Siamese bore, application, in both 1 and 2 piece rear seal configurations.

Both the Sportsman and Pro series blocks offer 16º splayed main caps, the difference being the SP series is nodular iron and the Pro blocks are 8620 caps. They are both CNC machined, flat and roller tappet capable, with a mechanical fuel pump boss. The Sportsman blocks are rated @ 800 HP and the Pro blocks @ 1200 HP.

Let me know what assembly you will be using and I will supply the part number for the Bowtie block that will fit your needs.
Bob

e8411a

Thanks rmbuilder,

The engine I am building is 500 to 600 horsepower. You speak tech talk that I don't completely understand. What does 16 degree splayed caps mean? Also, I know the block I have is a "siamese bore" but what does that mean?

Basically, the bearings went in the old block and cracked it in the saddle. All other parts have less than 20 hours so I am trying to use them.

rmbuilder

e8411a,
Here are the part numbers for the Sportsman Bowtie Block:

25534363
Standard deck 1 pc rear seal
4.494" Finished bore
4.600" Max Bore

25534362
Same as above w/ 2 pc rear seal

Bob

mcollinstn

Honestly, if you are only aiming for 600hp, then you may as well use a standard 502 MkIV block.

You can probably sell your "good" Bowtie block to a dragracer, and net enough change to snag a pair of usable 4.470" MkIV's and rebuild both mills. The Bowties are desirable.

e8411a

Interesting,

How much is a good Bowtie Block worth. And, will my crank work with a standard block?

mcollinstn

check a dragrace parts forum for pricing estimates.

A 4.00" MkIV crank is a 4.00" MkIV crank. Your stocker will be externally balanced. You can use an X-bal crank or an Internal balance crank as long as you match them to the correct balancer and flywheel.