Buy Holley 502-6 670 CFM Replacement Throttle BodyHolley 502-6 670 CFM Replacement Throttle Body Product Description:
- Direct factory replacement
- Increases area by 42-percent over stock parts
- Increases torque and horsepower up to 25-percent
- Comes with dual venturii, gaskets, injectors, and throttle position sensor
- Compatible only with factory electronics
Product Description
This replacement throttle body is a direct factory replacement for original equipment units and is made from cast aluminum. It features 2 throttle bores to provide increased air flow for more torque and horsepower and it is engineered for a bolt-on installation on stock factory manifolds. It includes an air distribution ring and is fully-compatible with all original equipment plug-ins for a quick installation.
Customer Reviews
Most helpful customer reviews
1 of 1 people found the following review helpful.
Works very well
By Jimmy Z
Adapted to an application not supported but works very well. Tech support from Holley was quick and very helpful. Really made an improvement over stock TBI.
0 of 0 people found the following review helpful.Warning: Objects in Mirror are Losing
By Krisanie
I purchased this product for an '88 Chev Silverado 4x4 350 SBC as part of an overall project. Project included removing smog pump & cat, mid length headers 2 to 1 with a 3 inch Flowmaster to the back. Upgraded to 3 wire O2 sensor, lowered thermostat to 185, and set timing to 6 BDC on an improved JEGS distributor & coil.So, that's the basic bottom, stock heads and cam. I chose the Holley Pro-Jection intake because the stock one and the competitor that starts with an "E" have (I believe)have 1 11/16 inch bores, while the Holley has 2 inch bores...42% more surface! Installing the larger bore manifold left me with options for the future. However, the installation was a PITA because ya have to grind just a bit off the front of the intake manifold...a few tenths...to clear stock accessory brackets, the fuel lines need to stretch, and the cables bracket has to be reworked so that your accelerator, cruise control, and most important, TV cable work correctly. If you don't get that TV cable right you will burn up a auto tranny quickly.Anyway, Once you get headers, intake, and ignition installed you can feel the difference, and the only thing left is fuel delivery...the TBI unit. I looked at a lot of upgraded stick units, big block injectors and fooling with the pressure but rather than mess with all that, why not spend just a bit more ($500 rather than $350 or so)and take advantage of the larger bore with the Holley TBI? The real difference is that the stock TBI is about 450 cfm, while the Holley 502-6 is a whopping 670 cfm! Again, 1 11/16 bores stock vs. 2 inch bores on the Holley. At cruising speed it will consume exactly as much gas as before, but stomp on it...It brought back the good old days with my Holley 650 Spread Bore Double Pumper :)The one negative thing about the installation: When I started the truck it ran but was severely over fueling...wet exhaust, the whole bit. I found everything I could online which quoted various fuel pressure values and setting them...definitely over fueling...then Holley Tech Support told me to move the vacuum line for the MAP sensor from the factory location on the back to a manifold vacuum port on the front to correct Absolute Pressure issues, and the truck started running just fine. Put hose clamps on both ends of this critical vacuum line. Also, spend some time setting up your idle and Throttle Position Switch....you will need a digital voltmeter...it sounds difficult but is very easy once ya mess with it. Stick the meter probes right into the back of the connector while it's attached...they are made so you can do that.So, how does it run? Holley advertises "up to" 25% more hp. This was the final, crowning part that I have installed and it made everything else start to work at their greatest potential. This 350 now flows air/fuel like you wouldn't believe, and it is all on stock TBI heads and cam. The factory advertises the '88 350 as 210 hp, and between the useless parts removal, headers/exhaust upgrade, and this Holley intake and Injector unit I have picked up somewhere between 30-40% (I hate to say more) and you can really feel it, no question about it. I am guessing that my 210 hp 350 is somewhere closer to 275 hp, give or take. My target was 300 and I think I am close...I hate to guess at numbers, but I'll be glad to meet you on Open Track Day! :)But more than that, the 350 is rated at just over 300 ft/lbs of torque, and now it has a crazy amount of it. The stock cam/heads combo are very torquey to begin with, just don't expect to go past 4800 rpm. But between two and four grand you get a great powerband and as long as it can breath it will settle down on its peak torque and stay there. We have a mountain pass (Stevens Pass) that has a couple of mile stretch of steep grade, gaining a couple thousand feet. You get to spend several minutes with your foot to the floor watching the speedo drop and it really separates the men from the boys. When I open up those twin two inch TBI bores to WOT and listen to the music of the headers and 3 inch exhaust, it was worth every penny. I would recommend this Holley Improved TBI but suggest that you get it as part of a general upgrade...you won't be sorry.
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