Talking to my machinist about my 396 build and were gonna make it strong. he wants to fill the block but is concerned about the knock sensor...what do i need to do to make this work right?

 

If it's a street motor you only do a half fill. I don't know if it effects the KS since mine is disconnected. Fill is not needed for anything than a high boost/big nitrous setup. Even then, maybe not.

Rich

 

want it was a street car....but it will be on high nitrous(200-300)

 

Only a lowly 381, but no block fill with a 300-shot. Buddy of mine made 1,125 flywheel HP with 20#+ boost on a 383 and did not fill the block. Shop recommended strongly against it.

 

i sprayed a 350 shot on my 355, no block fill, 300 realy isnt that big once you get into a straight up drag car.

 

But ...... to answer the OP's question ...... before you pour your block you place a 7-8 inch long 3/8" OD natural rubber hose, (that has been coated with either heavy grease or Vaseline), through the knock sensor opening, and run it up past the block deck. After your pour is complete and the block has set a minimum of 24 hours, take a hot air dryer, heat the rubber hose and pull it out from the block leaving a nice "cast" in water passage through the block fill to the knock sensor opening.

 

Im excited for you derek! cant wait ride in this thing, these guys know their stuff

 

also...will a 396 need a small base cam?

 

depends on the rods.....but probly so

 

Thats insightful! Is that 383 an LT block?

If that guy and hold that much power and boost with no fill I think we can lay this to rest....in my eyes anyway

 

I know of a car where NA he managed to crack a block from a head bolt hole to the cylinder. Was north of 500rwhp through an auto and makes a LOT of passes sucessfully running in a couple classes at a time.

Point being I think more than just a raw power number needs to be considered, like how often will it have to endure that power?? The block does flex and just like many other pieces of metal we have all handled you keep flexing them and they make take it for awhile but can eventually crack. So ask if the big number cars are just exhibition cars that make maybe a dozen full passes a year, or are they making a dozen full passes a weekend? Then apply the answers to what your plans are. Devil is in the details and too few people put forth the effort to understand them.

 

Yes... that was an LT1, stock 4-bolt mains (with studs and billet caps), a Vortech S/C running over 20psi. Car ran 9.05@155mph in a 3,900# convertible. When the block was eventually torn down (he opted for a Dart Iron Eagle block, and pushed it to 1,350 @ the flywheel), the LT1 block was in excellent condition. He sold it to a guy that was building a 1,000+ HP nitrous motor, but I don't think the engine was ever completed.

I would suggest you get your block sonically checked for cylinder wall thickness, and limit the overbore to 0.020" to keep the cylinder walls stronger. The extra 1.96 cubic inches isn't all that important.

 

Personally I think some folks are going cubic-inch crazy. The amount of money spent for 13 cubic inches, on top of the possibility of clearancing right into the water jackets and water leaking, the cylinders being taken to their max bore, which makes them less rigid and actually takes away power... I'd be willing to be there isn't a gnat's whisker of a power difference between a 383 and a 396 with everything else being equal... But there is a hell of a cost/headache/reliability difference!