coolcvi 11 Report post Posted November 19, 2013 I have a 302 from a 1998 doner car. The old carb is in need of replacement. Thinking about a Holly, but the choices are confussing. Engine is bored .030 over, mild cam, Torker 4 barrel intake manifold, going to be for street usse, T-5 manual transmission. Thanks, Dan Quote Share this post Link to post Share on other sites
Max Power 74 Report post Posted November 19, 2013 If you have stock heads, you don't need that Torker and a 600 Holley would be plenty. Quote Share this post Link to post Share on other sites
jholmes217 65 Report post Posted November 19, 2013 I'd go with a 570 cfm Holley Street Avenger, A Summit 600 cfm, an Edelbrock 600 cfm, or a Holley 600 cfm, all vacuum secondary, or a Autolite 4100. With that mild of a motor, I wouldn't go over 600 cfm. Quote Share this post Link to post Share on other sites
LoneWolf2U 136 Report post Posted November 19, 2013 Run a Summit 600 vs its a plug and drive carb. Quote Share this post Link to post Share on other sites
juit 34 Report post Posted November 20, 2013 for street later motorcraft 2150 models with the high-speed air bleeds Quote Share this post Link to post Share on other sites
therebel 10 Report post Posted November 25, 2013 I've had good luck with Holley double pumpers from mild to wild engines. Quote Share this post Link to post Share on other sites
buening 63 Report post Posted November 25, 2013 Run a Summit 600 vs its a plug and drive carb. +1. Good carb Quote Share this post Link to post Share on other sites
bomccorkle 12 Report post Posted November 25, 2013 A smaller demon would give room to grow. Quote Share this post Link to post Share on other sites
wilcoxfe 10 Report post Posted November 28, 2013 Ok, so I went with the Holly street avenger 650 cfm. I'm wondering if I messed up and should have gone with the smaller carb (like the 570). Would it be worth my while to stick with the one I've got, or should I consider trading it out? What kind of performance would I notice? Quote Share this post Link to post Share on other sites
SA69mach 39 Report post Posted November 28, 2013 The 570 Street Avenger is a very good fit to the 302. Vacuum secondary and electric choke. The 650 or 670 SA you have is a little oversize. You will be wasting fuel and will not get the same crisp response off the line with too big a carburetor. A nice set up would be the 570 SA on the dual plane Performer RPM. One inch phenolic spacer will give you improved velocity and increased plenum size, which works with a smaller carb very well in a 302. Ideally you would want a matched cam, but the three items listed above will give you a nice improvement and good response to 5500 rpm. Quote Share this post Link to post Share on other sites
wilcoxfe 10 Report post Posted November 29, 2013 The 570 Street Avenger is a very good fit to the 302. Vacuum secondary and electric choke. The 650 or 670 SA you have is a little oversize. You will be wasting fuel and will not get the same crisp response off the line with too big a carburetor. A nice set up would be the 570 SA on the dual plane Performer RPM. One inch phenolic spacer will give you improved velocity and increased plenum size, which works with a smaller carb very well in a 302. Ideally you would want a matched cam, but the three items listed above will give you a nice improvement and good response to 5500 rpm. Thanks SA69mach, I should have mentioned, I have a 351W bored out to .0003. I have a thumper cam. It took some tweaking, but we got the carb (Holly Street Avenger 650 cfm) finally set. The car has pretty quick response - yet I've heard a couple guys mention that the carb is oversized. With that said, Would I notice a big difference by going to a smaller carb? Quote Share this post Link to post Share on other sites
SA69mach 39 Report post Posted November 29, 2013 a 650 Holley is nicely matched to a 351W. I thought you had a 302 roller from a 1998. A 30 thou over 351W with a thumper cam. Do you have more information, like compression ratio, is it hydraulic flat tapped, or roller engine. Intake? Heads? I am not sure if this is the same engine package from your first post. In very general terms, smaller carbs with a taller intake height will provide faster flow velocities and will give improved low rev response (all things being tuned right - like timing etc). But you will reach a point with a undersized carburetor in its capacity to provide fuel at high revs. The 650 is considered by many to be too big for a stock 302 engine. I happen to agree, but that doesn't make it true for all applications. Cars are used for lots of different purposes. For street use on a fairly stock 351 Windsor the 650 Holley is a good match. No you would not notice a big difference by going a bit smaller. 390 cfm would be as small as I would even consider on that engine and you will definitely notice it. 570 Street Avenger - hardly notice until 5200-5500. spacers have 2 advantages. they insulate the carb from engine heat, and they add height to the stack, increasing air/fuel velocity. If you have a Street Avenger, it is a 670 cfm, not 650. Quote Share this post Link to post Share on other sites