Dart Big "M" 396 Sportsman block...
 

Just wondering if anyone has had any experience going to 4.185 on these blocks? How much is left? MB.

Re: Dart Big "M" 396 Sportsman block...
 

I deal with a lot of Dart blocks, The Dart Big-M blocks start at 4.240 bore all the way up to 4.590 bore.

Dart Little-M blocks will go 4.200 no problem but once getting out that far its best to use a .950 reach stud and bottom tap the head bolt holes, drop a ball bearing and bottom the stud out on the ball bearing VS the deck.

Re: Dart Big "M" 396 Sportsman block...
 

Maurice,
There is one in that white Corvette you like, I special ordered it last year. Solid piece. Dick Maskin told me the casting box for the 396 block is different. I will see Dick Saturday at a tech conference, I'll confirm that again. Jimmy has my number if you need it.

Re: Dart Big "M" 396 Sportsman block...
 

A sonic test would give you the best results. Does that block have Siamese bores?

I did get your PM

Carl

Re: Dart Big "M" 396 Sportsman block...
 

Carl…I don't have the block yet, researching the best options for my combination. They are a BIG "M" water block and not that common. Thank you for your response. MB.

Re: Dart Big "M" 396 Sportsman block...
 

Alan… Thank you for your time yesterday. North of the Border our approach towards things generally require additional research, it helps offset the additional cost. Our questions to the manufacturer on Saturday, may bring additional options to their product. Thanks again…Maurice.

Re: Dart Big "M" 396 Sportsman block...
 

I have worked with two of these. The paperwork says they are safe to 4.600. It is the same casting that the 427/454 version is made from. The 396 version weighs 290# as it comes from the crate. A great platform but very heavy.

Re: Dart Big "M" 396 Sportsman block...
 

Arnold… Your response is appreciated. Do you still have the paperwork? Thank you….Maurice.

Re: Dart Big "M" 396 Sportsman block...
 

Dick Maskin was not well, and not able to attend the tech conference Saturday. However, he did send a block expert to stand in.

On the 396 (4.094" bore) bock, which is a different casting, and does NOT have siamese bores, they consider the maximim bore size to be 4.350". Maurice, you'll want to call me Monday about your other questions.

Dart also announced a 305 version of the Little M block, which is legal for both Stock Eliminator and Super Stock.

Re: Dart Big "M" 396 Sportsman block...
 

Maurice, I still have one of the blocks to assemble, so I am sure the paperwork is still at the shop. I will look for the machining paperwork Tuesday and get back to you.

Alan, both blocks that I have built, have siamese bores and the same casting # as the 427 Big M block. Also both blocks were around 4.11??? on the bore size. They were both purchased through Atech. I will try to call you later this week when I am at the shop, probably on Tuesday. The first block had blind head bolt holes, but the latest has two on each side that goes into water.