What to do

[gbg57chev]

New here and looking for some advice. I've got a 2008 502 crate motor in a 57 Chev Prostreet. I'm looking to push the HP to 650/700 without taking the engine apart. Al. heads, cam and new intake with big four barrel is my thinking. I like the heads from AFR but what cam and intake? It's running 9.6 CR now and I want to keep it on pump gas. The internals are all forged from GM.

[34_40]

Hello from the other side of the country. It's good to see you here and Welcome.

There's a few guys here that can help answer your question(s) and they'll be along soon.

I just wanted to stop in and say Hi. 8-)

[jerry clayton]

Hello and welcome aboard!!!!!

Not taking the engine apart? but changing heads, cam, intake--------well you will have radiator out, water pump off, front cover/dampner etc for cam change so about the only thing you won't have apart is the lower rotating assy-crank, rods/pistons---------

[gbg57chev]

Hello and welcome aboard!!!!!

Not taking the engine apart? but changing heads, cam, intake--------well you will have radiator out, water pump off, front cover/dampner etc for cam change so about the only thing you won't have apart is the lower rotating assy-crank, rods/pistons---------

Yea, that is most of the engine. I just didn't want to buy new internals or have to wrestle that beast out of the car! I do have a leak in the trans tail shaft that has to be fixed so maybe I should just "bite the bullet" and do it! Still in the planning stage so it's "easy to do".

[techinspector1]

The cam that's in the motor is very well matched to the static compression ratio, 224 degrees intake duration, 9.6:1 SCR. If you opt for more cam, which will extend the intake closing point, you'll need to raise the SCR to match. For instance, moving from your 224 degrees of intake duration, up to 230 degrees of intake duration, will require a minimum of 10.0:1 SCR. Moving up to 236 degrees intake duration will require a minimum of 10.5:1 SCR. Moving up in cam timing without raising the static compression ratio will result in the motor being a pooch on the bottom and mid-range. There is no free lunch. You might be able to use a little more cam due to the cylinder packing and subsequent cylinder pressure improvement of using the AFR heads, but I'd be conservative here. Call up your favorite cam grinder and talk with a savvy tech guy. Matter of fact, call several cam grinders.
http://www.cranecams.com/contactus.php
http://howardscams.com/contact.html
http://www.iskycams.com/contact-us.html
http://www.crower.com/contacts#tabs-1

I'd opt for the AFR 290 heads and back the whole mess up with a 10", 3000 stall converter. Use Fel-Pro 1047 or AFR 6849 head gaskets. Weiand Stealth #8019 would be my choice of intake manifolds. Edelbrock does not make a BBC high-rise, dual-plane configuration except the Air Gap, which I consider a redheaded stepchild, more targeted at marketing B.S. than performance. Reports of poor performance (poor throttle response) in cooler climes has convinced me that you don't need an open type intake manifold on a street rod. You need the heat of the motor to help turn the liquid fuel into vapor for good throttle response. You may be thinking of using a single plane intake manifold, but for the rpm range of the ZZ502 cam, 1500-5500, you will find that the motor will make more power under curve with a tall dual-plane like the 8019.

Now, the thing that I would be most interested in doing is to insure against detonation on pump gas by tightening up the squish/quench to between 0.035" and 0.045". This would require complete disassembly of the motor to cut the block decks to zero deck, with the thickness of the head gasket being the squish/quench figure.
Fel-Pro Performance Head Gaskets 1047 - Free Shipping on Orders Over $99 at Summit Racing
You can't use a steel shim gasket to get there, the heads won't cooperate. They will fret with a solid gasket. You need a composition gasket that will give a little.
I know you have no intention of doing this, but think about the increased cylinder pressure from the increased flow of the air/fuel mixture into the motor through those far-superior AFR heads. I would either cut for zero deck or be thinkin' about some water injection. Of course, I'd keep a close eye on the plugs for signs of detonation before I'd do the water.

CFM Intake flow comparison ZZ502.../...AFR290...DIFFERENCE...PERCENTAGE OF DIFFERENCE
0.200".......138.......163.......25.......18%
0.300".......193.......235.......42.......22%
0.400".......233.......289.......56.......24%
0.500".......272.......330.......58.......21%
0.600".......299.......360.......61.......20%
0.700".......318.......375.......57.......18%

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[rspears]

Tech, what I like about your answers is that you tell a guy what to do based on sound reasoning and experience, then you take time to explain why it's the right approach, and then what not to do.
Gbg57chev you can take what Tech tells you to the bank! Welcome to the forum, and looking forward to hearing more of your adventures, along with pictures when you have time!

[Jematt]

Just put a small 150 Hp NOS kit on its cheep you don't need the extras a big kit needs.