454 rocker arms

[abad66ss]

can someone tell me what the factory rocker arm ration on 454 engines?

[bobss396]

They should be a 1.5:1 ratio.

[MrPbody]

BBCs are 1.73:1 in all applications stock. The small block is 1.5:1...

Jim

[bobss396]

Originally Posted by MrPbody

BBCs are 1.73:1 in all applications stock. The small block is 1.5:1...

Jim

Ooooppps.. I wanted to see if anyone read these threads. You are 100% right, the stock ratio is 1.7:1, I don't know what I was looking at, obviously the wrong line in a Crane catalog!

Bob

[abad66ss]

awesome thank you for the help, i have another question as well. what is the stock cam size for the 454? specifically a 2bolt main oval port head if it matter.

[MrPbody]

According to Melling (published specs), the "small" cam is 193/[email protected]" lift, .409/.442" lift, LSA 110 (int CL 104, ex CL 116).

The "big" one is 210/[email protected]" lift, .453" lift (both), LSA 111.5 (int CL 106, ex CL 117).

These are the standard issue hydraulic, flat-tappet cams. The "special high performance" (as they're listed in the Melling catelog) cams are quite different. These are what you would find in a typical pickup or Impala of the mid '70s.

What would you like to do with this animal? I may have input.

Jim

[abad66ss]

well, story starts that i got a 66 SS Chevalier project car and a good friend of mines father had a 65 that he was building at the same time. so he would go nuts on eBay and everywhere else and buy any good deal he could find. so when he had multiple items i would take my pick from his stash. So he found a supposed 500hp 454 bored .030 over, with all the goodies. So he found a 496 short block. So haven the two he took the complete 454 and make a complete 496. so for a fair price i picked up the 454 short block. (casting number3999289). it has the stock crank as far as i know with what looks like forged I beam rods, and domed pistons (big dome). Also from his stash i got a holly 850 carb double pumper, and the 660/666 lift 292 duration mechanical roller cam that was in the engine when he got it. In my own search though craig's list found a guy getting rid of six sets of bbc heads for a price i felt i could not pass up. they are all oval port, open chamber heads, 113cc i believe. all from mid 70s trucks if i remember right. at this point i have too many ideas in my head of how i should play this out. #1 plan was to redo the internals with 9:1 pistons, get a fuel injection kit, and do a street-able twin turbo set up. backed with a t56 6speed. #2 why not go with a ls1 as it is already injected and already backed with the t56, and twin turbo with the components to pull it off.#3 just take the existing block and internals i have now, use one of the set of oval ports i have. do a mild cam, dual plain manifold with the 850 carb i have, and rebuild the power glide that is in the car right now with a nice shift kit and maybe a trans brake setup, just something to hold me over tell i figure out what i want to do. one thing is for sure, it will be turboed, and it will be street-able.

[MrPbody]

The turbocharged idea isn't without merit, but very expensive and rather cumbersome to keep in good maintainence. Perhaps a ProCharger would be a better choice. ProCharger is a belt-driven turbine, and is very "street friendly".

The bigger engine will make more power. The blown big block is pretty much out of reach for any small block, especially at the same level of tune, including the newer LSx engines. The Chevelle LIKES the big block, as the '66 SS was a very good car.

I would rethink the PowerGlide, though. While strong enough, it's woefully obsolete for a street car. 2 speeds just don't cut it. TH400 is a MUCH better choice, and if you get a good one (aftermarket, not cheap), it will work with the mild big block AND the blown one. That mean you only spend the money once. A manual would be even better, but they're very expensive (at a level that can withstand that much power).

Jim

[abad66ss]

lol yes i have been too the world of turbos, and varies blower for quit some time now, but thank you for the description just the same. see for the the super chargers roots and centrifugal are cool and all but the turbocharger rains supreme. yes i know that the roots makes outstanding low end torque, but it can only spin as fast as the engine. that means that when u have the vehicle stalled up at the line say with a 3000 stall converter (staying streetable) a root blower is only seeing 4-5 psi of boost depending on blower size and pulley. were as the turbo stalled up at the line 3000 stall converter u could be seeing in the area of 6-10 psi boost, and then if u have be ability to run an anti lag set up (this is a computer controlled launch controller, what it dose is retard ignition timing to the point were it sparks while the exhaust valves are open, sending the now ignited a/f charge out and into the exhaust header witch rapidly increases exhaust pressure and spools the turbo twice as fast than just haven the car on a stall converter). so with the anti lag on a 3000 stall you could see between 10-full boost depending on how u like it set. and in terms of street driving it like i said before the blower spins as fast as the engine. so a 65-70 mph the blower is spinning and trying to make boost witch means that u have to throw enough fuel in so it dose not detonate, in turn taking away from gas mileage. the turbo at 65-70 yes buy the exhaust gases is spinning but it is not spinning fast enough to make any boost pressure and the manifold is in a vacuum like and naturally aspirated car would be, witch means that ur using as much fuel as a low compression n/a engine would need to go 65-70 mph thus having better gas mileage as the blown car. this is my reasoning be hind the turbo ideas, plus the fact that i think there just over all better