mr.beachcomber

On the older small-journal blocks that used a PCV system rather than a road draft tube, the oil filler spout was the pick-up point for crankcase vapors that were routed to the carburetor via the PCV. These systems used an oil filler cap to seal the system. Replacing the filler cap with a breather open to the atmosphere defeats the purpose of having a closed system in that the PCV system's suction will draw in primarily outside air rather than evacuate the blowby from the crankcase. Going back to a sealed system is a must unless you have some other type of crankcase ventilation system in place.

Hope this helps!

burgessdg

Pretty sure that even with a pcv valve you still need an entry point for air. Otherwise you`re pulling a vacuum on the crankcase which in my experience sucks the valve cover gaskets into the motor. Not so sure about the early pcv`s, but I can tell you 70`and up had a breather in the air cleaner that did indeed allow outside air to enter the crankcase and allow the pcv to evacuate the crankcase.
I`ll do some research on the early ones, but I would never recommend a pcv without a breather,

My 2 cents,
Dan

mr.beachcomber

You must have an air entry inlet for a functional system. The small journal blocks had their inlet for the PCV system at the back of the block. The PCV system picked up clean, filtered air from the air cleaner assembly and routed through a hose attached to an inlet assembly bolted into the old road draft tube hole used to evacuate the crankcase to the atmosphere prior to PCV systems.

sbcbuilder

It is a real science to upgrade an older engine with new technology. Every thing has changed in the art of building a motor. Remember that an engine is an air pump, nothing more. Air in, Air out. Every thing must be matched so that things flow correctly.

The older high performance engines had small heads in terms of flow rates. A perfect example was the 396 bbc oval port engine. This was a better street combo that the big port heads. A simple matter of flow at low speeds. Take into consideration your gear ratios and at what rpm your cam comes alive.

Plug your trans and final drive ratios in this chart and look at the various speeds in each gear, then design your set up from there.

http://weddleindustries.com/gear-calculator

Some older engines were very peaky. The 302 Z/28 a perfect example, stock from the factory was a good street set up, but every one went nuts when they seen a cross ram set up, This was for racing only and only worked above 4500 rpm.

Yes the small journal engines did rev very quickly. If you have the dollars go for main cap studs, it will make a difference.

Yes a sleeper attitude is best. I had a 66 Chevelle that came with a 283. I bought a 327 engine out of a 65 Corvette and swapped the 283 for the 327. I put the 283 2 bbl intake and valve covers on. Used a 500 cfm Holley 2 bbl and adapted the stock 283 air cleaner.

Every thing else was bone stock except the transmission - my friend ran the local speed shop and he sold me his racing powerglide, 4500 rpm stall. He set it up to shift at 6500. I would cruise in high gear at 30 mph and when any one wanted to race I would just floor it and down into low gear we go. The engine would just rev very fast and jump a half a car length ahead. A very fun car to drive.

No mag wheels or any thing like that, just a nice leather custom seats and a black/blue metal flake paint. I beat many cars and when they looked under the hood, they could not believe what they saw. I did do another trick, I put a 9000 rpm auto meter tack with a tell tale out of the dragster, the tell tale was stuck at 8500.

uxojerry

I love your idea of a high rpm sleeper that looks 100% stock. I think that could be achieved using a good after market aluminum top end. Some sand paper and paint can make it look stock.

A similar build is the hot rod DZ 302 build article, "She's a Spinner". They built a stockish DZ 302 and it dyno'd in the low 400s. They installed afr 210 heads and the engine made 540hp at 7300rpm with no cam change.

Your engine with the afr 210s would probably hit the same hp at 7000rpm or less. If you want iron heads, look at the Dart iron eagles or equivalent. Make sure your heads have the cfm for a high rpm power band and cam accordingly.

Mark Jones would be an excellent guy to talk to as he specializes in porting iron heads and intakes. A porter can also maximize you combustion chamber to ensure you get the optimum compression ratio. I love builds like this.

I recently had a short stroke BBC built that everyone said I shouldn't build, lol. They said it would be a dog and a waste of money. When the builder was assembling it, he was very closed mouth about his expectations. I finally asked him what he thought it would make? He said he didn't know whether it would make 650hp or 800hp as he had never built one. The engine made 810hp/660tq at 7000rpm.

I wish you the best of luck and hope you achieve your goals. I would make sure your heads have at least 250cfm at .5 or .6 lift to ensure you can hit 500hp at your desired rpm.

sbcbuilder

Speaking of DZ302 sleepers have a look at this video

It is a Camaro but you get the idea

uxojerry

The NRE video does show how easy it is to take modern parts and make them look like traditional stock parts. Super Chevy has a decent 327 build with afr 195s that makes 540hp or so. The article has an in depth build plan. Google 500hp SBC 327 build and the article will pop up.