I want to put a 2bbl carb on my 250, and upgrade the dizzy to a DUI. what is the purpose of any vacuum in this situation? or will I be able to just attach the carb (with an adapter plate for now till I get the head machined) and hook up the dizzy? Or am I missing something here? I was reading the Classic Inlines articles and the whole manifold, ported and such has got me all messed up
Its not the power gains im worried about, its just will it be able to be driven in between the upgrades? all the vacuum stuff had me confused. I don't have alot of money, so it gets built at a little slower pace. I'll probably be getting the weber 30/32 progressive carb, so if I do an upgrade to a DUI, will I be alright?
If this is the case....I really don't think this is a road you want to head down. Save your money and do it all at once.
The Duraspark distributor is a far better design than a DUI...and about $250-$300 cheaper. You want vacuum advance unless you drive wide open ALL the time. Without replacing the cam...the only thing a 2 bbl will do is let you smell raw gas. If you do replace the cam then you need a header to get the exhaust out before you can start thinking about putting more gas in.
I agree... build the motor then put the gas to it... here is one I built but sold the car before I got the 2 bbl carb on it.
This is just basic hot-rodding type stuff. Start with the most effective gains first or upgrade the worn out parts to better stuff during maintenance. Exhaust is horrible.. factory style muffler makes things even worse. In the scheme of all things "bolt on", mufflers are extrememly cheap power and easy to do on a budget. Tons of designs out there but the old Dynomax turbo's are still decent designs and sound good without being obnoxious at all. Free flowing filter element can help maximize what you already have. The cheaper filter elements flow more air because.. well.. they are cheaper, don't filter quite as well, and therefore aren't really intended to be used as long. Fresh one every 3-4 months or so will still save you money in the long run if you rack up some miles. Ignition. Yep.. duraspark with a hotter coil, premium lower resistance plug wires(not sure who makes them in kit form for these particular motors, so cut to fit "universals" may be in order here.. but WELL worth the extra effort), and platinum plugs will make it run better all around. PS. many also don't fully realize how much hidden power is left in the stupidly retarded ignition curve of these motors. Find someone who knows how to recurve it and you will be amazed at how it will pull all of the above together to make more power from idle all the way to the overly premature redline. Once all that is done.. you can tackle the bigger chokes.. manifold and carb.
You hit the nail on the head when you bring up ignition curve. That was the best bang for the buck on my 6 cylinder...night and day differences...best $4.25 I ever spent. Went from a '78 Plymouth Horizon performance to a (almost) V8 in need of a tune-up performance. Pre-emissions timing gear and chain helps with the valve timing on these Emissions motors too. (Cam gear is one tooth retarded)
