CarburetorsCarb discussion and questions. Upgrading a Third Gen carburetor, swapping TBI to carburetor, or TPI to carburetor? Need LG4 or H.O. info? Post it here.
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Okay, so I have a 1991 Camaro with the p.o.s. 305. I just recently picked up a bone stock 1976 Corvette L82/210 350. I am going to be putting it in the car soon but wanted to replace a few things first (carb, manifold, headers, etc.) I am doing this build on a budget so I am looking for cheap stuff. I found a nice carburetor/manifold kit on Summit for a decent price. Here are my questions;
1.) Is this okay? Or should I go for a Holly, Edelbrock, etc. my friend rebuilds carbs and sells them for around $100-$200 should I do that or get this new one. Or a better brand name one.
2.) Do I get the 600cfm or the 750cfm? The links are posted below.
Well for starters both kits you have listed come with single plane intakes. I would stay away from those for a basic street car. You will want a dual plane intake. For a fairly mild 350 I would go with a 600 or 650 cfm carb. A 750 is a little much unless you plan on making over 400 hp with it. If you can get a carb from your friend for under $200 I would go that route. I ran a 600 cfm Edelbrock carb (1406) on my car for a while and it worked fine. Fairly easy to tune also. A lot of guys will tell you to get a Holley carb and that the Edelbrocks are junk, but they are a perfectly usable carburetor. I liked mine. If you have an automatic transmission, make sure you get a carb with vacuum secondaries, not mechanical. For a manifold, any dual plane intake should work fine, the most common would be a Edelbrock Performer or Performer RPM. For a mild motor a Performer would work great.
Not true. A proper sized mechanical secondary carb is fine with an automatic transmission.
If you are running an auto trans without a real high stall converter a vacuum secondary carb is an obvious good choice since your allowing the secondaries to only open when they need to be open- at high rpms when the motor needs that much air. If you're running a mechanical secondary carb as soon as you put your foot into it your forcing open all 4 throttle blades and this could be at a low rpm. All that does is slow down the velocity of the intake charge, allowing less air to fill the cylinders at this lower rpm, creating less power and usually a bog. Vacuum secondaries eliminate this problem by only opening when they are needed. Go to any carb manufacturers web site and you'll see it almost anywhere "For heavier cars with automatic transmissions a vacuum secondary carb is best especially with higher gearing and lower stall convertors. Mechanical secondaries are generally best with lighter vehicles/ manual transmissions/ or very high stall converters." I don't even know what you have for a transmission but do your research before you go on one person's advice. Would a mechanical secondary carb work? Of course. But it's not my first choice for an auto. Check it out for yourself. The choice is yours.
It is quite simple to choose the right mechanical secondary carb for your engine and car. Unless your goal is something other than performance, get a mechanical secondary carb.
For a stock '76 Vette engine, you don't want a lot of intake manifold. A simple Performer will be a good match.
A Performer RPM (one step up from the Performer, still a dual-plane intake) will fit under a stock hood with a drop-base 3" tall open element air cleaner.
The reason that vacuum secondary carbs is recommended is for automatics is because the average shade tree mechanic puts too big of a carb on a stock engine with a stock converter, and then wonders why it bogs on every shift when the recovery RPM is too low to pull enough air through the venturis to develop enough vacuum signal to pull enough fuel. Notice that you'd get a similar problem with too big of a vacuum secondary carb if you put a weak spring in it and the secondaries stayed open, or if you removed all the spring tension on the air valve on a Quadrajet.
If you had the right-sized double pumper and tuned it properly, you'd beat the right-sized, properly-tuned vacuum secondary every time, whether it was on an automatic or a manual transmission.
Thanks for all the help guys. I am probably going to ask my buddy who own the speed shop this summer if he can hook me up with a good 650. I will look for a good performer intake at a swap meet as well. thanks guys.
