73-87chevytrucks.com
73-87 Chevy _ GMC Trucks => Performance => Topic started by: ant305 on July 12, 2009, 11:58:12 am
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I have an 86 C10 long bed with a Jasper 350 .30 with a torque cam (10k miles). I have a Holley 600 carb, Edelbrock EPS intake and the heads are stock but were remanufactured when the motor was built.
I mainly use it as a cruiser and occassional trips to Lowe's or Home Depot where I fill it with home improvement stuff. I fully loaded the bed and pulled a trailer with fence material (for about an acre) and my truck pulled everything ok, but it struggled alot of the way and I have not been a happy camper since.
I have a brand new Holley 670 double pumper that came with the trick and 1.5 rollers from summit that I will swap out when I decide what i'm going to do. I recently found a Holley SysteMAX street system that makes 350 hp. It includes an intake, lunati cam, double roller timing chain and lifters.
There are the specs from Summit Racing:
Brand Holley
Manufacturer's Part Number 300-502
Part Type Intake Manifold and Valvetrain Combo
Product Line Holley SysteMAX Street Systems for Small Chevy
Summit Racing Part Number HLY-300-502
Engine Block Style Stock/OEM standard deck
Intake Style Dual plane
Basic Operating RPM Range Idle-7,200
Intake Material Aluminum
Intake Finish Natural
Carburetor Flange Square bore
Camshaft Included Yes
Cam Style Hydraulic flat tappet
Intake Duration at 050 inch Lift 218
Exhaust Duration at 050 inch Lift 218
Duration at 050 inch Lift 218 int./218 exh.
Advertised Intake Duration 268
Advertised Exhaust Duration 268
Advertised Duration 268 int./268 exh.
Intake Valve Lift with Factory Rocker Arm Ratio 0.457 in.
Exhaust Valve Lift with Factory Rocker Arm Ratio 0.457 in.
Valve Lift with Factory Rocker Arm Ratio 0.457 int./0.457 exh. lift
Lobe Separation (degrees) 110
Lifters Included Yes
Lifter Style Hydraulic flat tappet
Timing Chain and Gears Included Yes
Timing Chain Style Double roller
Intake Manifold Gaskets Included No
Valve Cover Gaskets Included No
Assembly Lubricant Included Yes
The entire kit is $377. My question is will the cam work with my heads or will they need to be opened up? I have considered a head swap to something with more flow but I wanted to wait a little longer because the enter motor is still pretty new. Motor was purchased in 2006 and the previous owner only put 2500 miles on the motor by the time I bought it last year. I'm just looking to give the motor a little more punch. Is this a good kit for the $$ or can someone recommend something else. Any help is appreciated.
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Well if you don't like the way it hauls heavy loads now with a small torque cam, you definitely won't like it with a mild performance cam. Bigger cams shift the torque curve upwards in the rpm band. The best way to turn that motor into a heavy load hauler would be to stroke it to a 383 and go for all the compression you can with the fuel you use. If it's just a limited use truck shoot for 9.5:1 - 10:1 and use premium fuel.
Also, if you have 882 or similar heads, they are junk, even on stock engines. Consider upgrading to L31 vortec heads, or if you want to keep your intake look for some good used World SR Torquers (they are just too expensive new) or Dart Iron Eagle S/S heads. The superior swirl characteristics and port velocity of any of these heads will improve power and efficiency.
A smaller vacuum secondary carb will definitely be better than a mechanical secondary carb for hauling loads. So I'd skip on the 670 double pumper, for this application. And you already have a good intake for a street truck, so no need to swap that out.
Before doing anything, are you sure your ignition timing is optimized. Then, is carb calibrated properly? Maybe your gearing isn't appropriate for the loads your hauling.