I am building a 383 SBC and the motor should make about 525 hp and then I'm gunna throw a 200 shot of nitrous at it. I was told that I would need to hard block the engine b/c the block wouldn't be strong enough BUT is there anyway to keep the engine running cool so that I can run it on the street?

Josh S.

P.S. This engine is going in a 68 Camaro and will be used for pretty much a street/show car.

 

Just make sure you don't do a complete fill. When you add the Hard Blok, just add enough to bring the level up to the bottom of the freeze plug holes, or, if you want a little more strength, fill to the bottom of the water pump holes. That still leaves you with a couple of inches to cool the top of the cylinder. Beyond that, there isn't a whole lot of engine heating going on anyway.

 

What kind of block?

Back in the old school days we had SBC motors with stock cranks and stock rods (with good bolts) running a 250 HP plate, and in many cases a fogger.

Just to give you an idea. In a full body full interior 68 Camaro with subframe connectors, traction bars, TH400 with a 10" converter, and a 4.11. The car had a 406in 2 bolt main motor with stock rods (good bolts), heavy @$$ TRW forged pistons, and a stock crank. On a set of pocket ported 461's w 2.02/1.60, and a 292H comp cam the car would run 11.80's all day long. On a 250 shot it was running 10.40's.

Motor street raced every weekend for 3 years before one of the rods turned loose. With a better set of heads, the car would have been a total beast.But nothing was avaliable at that time that didn't cost more than the whole car....

I know folks who have "rocked a block" but in most cases they are all out race cars. Alos, with the new "Little M" blocks you have nothing to worry about on blocks any more.

If you decide to do one, like they said only fill halfway. But, I don't think you need it....

 

I would be hesitant to use block filler for a street-driven car. If you need to stiffen up the block, you can also use a main bearing girdle. Milodon and others make them.

You could also use a Rocket block as the basis for your engine. They are much stronger than stock, & widely available from GMPP or SDPC.

BTW, the Hard Blok comes in a pre-measured "short fill" for street/strip & oval track cars, & a "tall fill" for drag cars.

 

I am going to purchase an aftermarket block for the next motor(434 or maybe a 454 small block), but I'm just going to keep this set up for now since I already have just about everything that I am going to need.

This is more of a lower budget engine for now( all good parts just not going to the extent of buying an aftermarket block yet).

I'm thinking that the stock block will be strong enough for the power output I'm planning on for now. But its always good to have a little insurance.

Josh S.

 

Has anybody used block filler on an aluminum block like the LS1? I know that the coefficient of thermal expansion of concrete (block filler) is about the same as cast iron, but some 80% lower than that of aluminum...

 

i wouldnt run it on an ls1. just get a girdle and you'll be fine.