Hey guys. I'm thinking about adding a 4bbl carb to my stock 302 (w/ C4 auto) with the stock 2bbl intake. I've got a few questions: 1) Is any adapter better than another? Will this massively affect what size carb I can use effectively? I'm looking at adding something like this until I do another rebuild and get a good intake. Here's what I'm looking at: http://shop.advanceautoparts.com/we...l-spectre_22905990-p?searchTerm=adapter+plate 2) What size 4bbl carb (w/ electric choke + ford AT kickdown) should I get? I'm reading that the Holley 390cfm 4bbl is good but anything up close to 600cfm will need some considerable tuning to run right on a stock setup. Here are some I'm looking at, but please let me know if there's something better for around the same price. http://www.summitracing.com/parts/hly-0-80457s/overview/ http://www.summitracing.com/parts/hly-0-8007/overview/ For these Edelbrocks....No ford AT kickdown? Am I missing something? Don't I need this (maybe sold as an accessory?)?? http://shop.advanceautoparts.com/we...chTerm=edelbrock+carburetor+600cfm#fragment-1 http://www.summitracing.com/parts/EDL-1403 Let me know what you guys think! I'd like to keep the carb between $250-$350. Thanks!!! If you know of any 2bbl carbs better than the Autolite 2100 (mine is 287cfm), please let me know of those options as well! Jory
I'm majorly against adapters so I won't comment further... There are different size 2100, the ones that came on 390 & 429 were 350cfm, will have 1.21 cast into the front left side... I had one but sold it to a circle track guy who was running in a stock 2bbl class... Sometimes there are deals on ebay, I got a Holley 670 Avenger that had not been used more than to bolt it on for $151.50 and that incl shipping... It would be too much carb for a stockish 302, I plan on using it on Trick Flow headed & cammed 331...
I'm usually the last guy to ask this but... why? Putting a 4BBL on an adapter plate for a 2BBL intake is only going to result in lower MPG from what I've read and been told. My bro-in-law the "automotive" engineer practically stroked out when I talked to him about it. He went on and on about how stupid it was to do and how it would do nothing but rob power. My opinion thous is to each his own. I would put on a 4BBL intake rather than an adapter plate.
http://motors.shop.ebay.com/i.html?_nkw=motorcraft+1.21&_trkparms=65%253A12%257C39%253A1%257C72%253A7088&rt=nc&_dmpt=Motors_Car_Truck_Parts_Accessories&_sticky=1&_trksid=p4506.c0.m245&_sop=15&_sc=1
FYI: kick down rod will not work with spacer. You will need a different rod. Check hood clearance 1st
They can and do make more power if the rest of the engine is tuned and tailored to make use of the extra airflow. I know because I've used them on at least 4 motors over the years. BUT.. you must use a vacuum secondary style carb and nearly shut off the secondaries with an overly stiff spring(and often a shim as well) to get them to run properly. Otherwise.. the 2brl manifolds are just too restrictive and the motor will bog and lose booster signal. IMHO.. by the time you mod everything.. or find a larger bore 2brl carb and get the linkage all set up correctly?.. you may as well just wait to do it right the first time around.
carb As with others I have tried the adapter from 4 Bbl to 2 Bbl....the results were not worth the effort. Ford used a Holley 2 Bbl on late 50's early 60's trucks, I dont remember what models. I have one and it worked very well and was cheap & the linkage dropped in place. 4 Bbl intakes are pretty cheap and I generally buy a 600 cfm Holley Vacuum Secondary carb and drop it on, Adjust the float level, idle speed and mixture and run it. Summit sells factory reconditioned carbs, my buddy bought one and it looks and performs like new for about 100.00 less........options so many options
Buy a 4bbl manifold first and run your 2bbl on it, then when you can get a 4bbl carb. If you're really on a budget check out the junkyards, theres usually one or two 302s with a 4bbl intake.
3rd.. I tried the plate when I was younger and the results were not like when I put on the right combo.. And like mentioned, the rod and linkage wouldn't line up..
Instead of buying the adapter and carb, just go buy yourself a 500 cfm Holley 2 bbl and bolt it onto the 2 bbl intake. I've used several of these over the past thirty-something years and it does make a worthwhile gain on even a stock 302. Using an adapter to put a 4 bbl carb on a 2 bbl intake is a huge waste of money. Oh, and the 2100 Autolites ? The "biggun" was the 1.33 bore carb, these are extremely hard to find items. Holley 500's can be easily bought new or used
I second the Holley 500. Mine ran great and would chirp the tires going into second on a stock 302 with 3.00 gears.
So, the 500's bores line up with the stock 250's intake? It's been far too long now.. but IIRC it took some grinding to make those things match up correctly.
