HICKL Posted May 30, 2006 Share Posted May 30, 2006 I did a tailpipe emisions test on my Z and she is way too lean. I have a holley 600 in which I have already opened up the jets. The dude told me I needed a 750 double pumper. I have never had one so I don't know much about them. I do have a Edelbrock 750 that needs a few parts but that guy said not to use it. (he didn't like them) Anyway just looking for opinions so if you have some, fire away. My motor is a 30 over 350 with flat tops, sportsman II small chamber 2.02 heads, Comp Xtreme energy cam and currently a torker II intake. Soon to be a performer or performer RPM. Est 10:1 static compression. Thanks, P.S. If anyone has a holley 750 for sale, let me know. Jeff Quote Link to comment Share on other sites More sharing options...
331CI 280z Posted May 31, 2006 Share Posted May 31, 2006 The Torker II intake is better than the standard Performer. I currently run a 750 DP, and am upgrading the main body and baseplate. There are plenty of tuning tricks to be done. If you want to dial in the carb, a Holley or Barry Grant is best. For set it and forget it, (but slightly decreased performance) Edelbrock is better. As with anything there are tradeoffs. You may want to consider a projection system. They are affordable on Ebay. Quote Link to comment Share on other sites More sharing options...
280zwitha383 Posted May 31, 2006 Share Posted May 31, 2006 Try this: http://www.csgnetwork.com/cfmcalc.html notice the 100% calculation IMO, the dude you talked to is of the bigger the better persuasion (which is not always the case). I can't imagine you not being able to jet your Holley to get an ideal a/f mixture. Seemingly, a smaller cfm carb will give you better throttle response. I was about to post what 331CI just said about the Holley vs. Carb thing so I agree with him. Both carbs have their place. Quote Link to comment Share on other sites More sharing options...
Paz8 Posted May 31, 2006 Share Posted May 31, 2006 Check the float levels on your 600 and the power valve, as stated before 600 Holley is a good street carb. How do the spark plugs look, what color are they? How does the engine IDLE, alittle fast and rough, intake or vacuum leak? Don't replace the carb on one persons say so, may not be the problem at all. Quote Link to comment Share on other sites More sharing options...
MAXIMUS Posted May 31, 2006 Share Posted May 31, 2006 What kind of horsepower you getting out of your motor? These guys are right,bigger is not necessarily better. That 600cfm should be plenty if your up around 500hp. I am running a 406 sbc that dynoed at 480hp/480ft/lbs torque Carbed with a 600cfm Holley. just put it in the car,hope to be driving it soon. Quote Link to comment Share on other sites More sharing options...
HICKL Posted May 31, 2006 Author Share Posted May 31, 2006 I tend to agree with you guys, I am only making probably 330 to 350 hp tops. I threw a Edelbrock 750 on there that I had laying around. I like the way it idles, lopes a lot more than with my 600 (I know, lower intake velocity). It bogs a little when the secondaries upen but then really sings once it catches up. I talked to a tech at Edelbrock and he said the secondary jets are too large out of the box for my app and told me which ones to try. It seems to rev much better with the 750 then the 600 other than the initial bog. I guess I either need to jet the 750 down or the 600 up. Probably better overall performance to jet the 600 up right? thanks Jeff Quote Link to comment Share on other sites More sharing options...
331CI 280z Posted May 31, 2006 Share Posted May 31, 2006 Your engine sounds like you've got some good parts on it. You should be able to handle the 750. You may have to dial in the secondaries. The single plane intake is more efficient than a dual plane, so you don't need as much carburation. Go and try to buy this book:How to Build Max Performance Chevy Small Blocks on a BudgetbyDavid Vizard, David K. Wright They have many good tips, and talk about carb tuning, booster signal, venturi size etc. They explain a great deal and if max power is your quest, you'll find that this book helps alot. Quote Link to comment Share on other sites More sharing options...
HICKL Posted May 31, 2006 Author Share Posted May 31, 2006 I plan to put a dual plane back on as I do notice the loss of low end with the torker II. The performer RPM I believe is the best choice for me but won't fit under the hood and I haven't found the right cowl hood (in my budget) yet. Quote Link to comment Share on other sites More sharing options...
jt1 Posted May 31, 2006 Share Posted May 31, 2006 Either carb should work fine for your combo if properly tuned. You need to learn to do it yourself, or find somebody to help out, preferably with a wideband 02. I run a RPM air gap under a stock hood, you just need a drop base air cleaner. They're a fine intake. jt Quote Link to comment Share on other sites More sharing options...
HICKL Posted May 31, 2006 Author Share Posted May 31, 2006 I wonder if the air gap is any shorter than the regular RPM. I didn't think either would fit under hood. I know basically how to tune my carb, but like you said, without the 02 sensor or a dyno, takes a lot of guess work. My motor has some blow by so my plugs tend to get oil wet which makes it hard to read them for fuel mixture. Other than that, seat of the pants is about all I have and that is highly suspect. I appreciate all the input though. What carb are you running on your air-gap? I have heard great things about those intakes, I have a regular RPM hanging on the wall but may have to get the air gap, especially if it is shorter. Thanks Jeff Quote Link to comment Share on other sites More sharing options...
HICKL Posted May 31, 2006 Author Share Posted May 31, 2006 Hey JT1, I just checked the edelbrock web site and the RPM Air Gap is the same height as the regular RPM. I had a drop air cleaner on my car with a standard performer and it was close. Can you please give me some info on what air cleaner/carb you are using? I am pumped that I may be able to use my RPM but don't want to make the swap to find it won't clear. Thanks a bunch. Jeff Quote Link to comment Share on other sites More sharing options...
331CI 280z Posted May 31, 2006 Share Posted May 31, 2006 It depends on what style of mounting you have. I have the Hooker style mounts and a Performer intake (not RPM) with a dropped base air cleaner and it barely clears the hood. The wingnut rubs the hood a bit. I have a set of AFR heads with a Victor Jr. and a 2" spacer and was considering the SS style hood that 280Zone offers, but was unsure if it would clear and I don't need another hood to take up space. Quote Link to comment Share on other sites More sharing options...
HICKL Posted May 31, 2006 Author Share Posted May 31, 2006 I am using the JTR setup. Quote Link to comment Share on other sites More sharing options...
jt1 Posted May 31, 2006 Share Posted May 31, 2006 Hickl, my setup is 1st gen 355, JTR mounts, Eddy performer air gap, uncut, Holley 700dp. My car has the 1/2" JTR spacers between the crossmember and frame. With a 1 1/4" drop base air cleaner, a repop Z28 style, I was using a 14 x 3" air filter with no problems. With a 1 1/2" drop base, I run a 14 x 4" air filter. This is very close and would not fit without the crossmember spacers, it has about 1/4" clearance to the hood. I made 501 hp @ 6700rpm with the unmodified air gap. It makes good top end and doesn't give up much torque lower down, like a single plane. Edit: A good easy way to check clearance to the air cleaner is take a piece of aluminum foil, wad it up into a loose ball, tape it to the air cleaner with duct tape, then gently shut the hood. The hood crushes the foil ball, and it doesn't rebound, so you can measure it. The closest place isn't the center, it's where the bulge on the hood blends back into the hood. John Quote Link to comment Share on other sites More sharing options...
HICKL Posted May 31, 2006 Author Share Posted May 31, 2006 Cool John, sounds like we have pretty much the same setup. I have the spacers as well on the crossmember. Tell me more about your engine setup, 501 hp is pretty impressive out of a 350. Was that tested on an engine dyno or in the car. I've got some pretty decent parts on mine and am not even close to those numbers. Quote Link to comment Share on other sites More sharing options...
jt1 Posted May 31, 2006 Share Posted May 31, 2006 It's a 355 flat top motor, 10.3:1 compression, Canfield 195's with a bowl cleanup/blend, Comp solid roller, something like 248/252@50, 580/586 lift, air gap, MSD 6AL. With the 700DP, which has the tower cut off and blended, it made 480hp/429tq at 6500/5400rpm. With a 830 annular, it went to 501hp/448tq at 6400/5100rpm. Crank horsepower, 93 octane pump premium, 36deg timing. It ran good enough to split #2 & #4 main caps at a track event one day last month. I was using a mid 80's mexican block which was a POS. I'm currently rebuilding it with a 72 010/020 block, with milodon caps. John Quote Link to comment Share on other sites More sharing options...
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