check out the newish 625CFM Street Demon(totally new carb design), by Demon carbueration, which is now owned by Holley Performance since Barry Grant filed for bankruptcy..so no worries on quality control anymore possibly best street carb choice now-adays edelbrock performer AirGap would be a good choice for intake 2.25 or 2.5 exhuast will do you well if you like the typical throaty/rumbly exhaust , dont do a cross over H pipe is easy to add during or after install If going with an X-pipe, best design(wont crack at seams) will be Pypes Performance
Real output numbers from Ford Stock 302, cast iron manifolds, single exhaust, standard 1.08 2V carburetor = 140 HP @3600 RPM and 250 FT -LBF @1800 RPM HO 302, 351 camshaft, cast iron manifolds, single exhaust, HO 1.21 2V carburetor with enriched metering circuits = 165 HP @ 4200 RPM and 240 FT -LBF @ 2400 RPM HO 302, 351 camshaft, steel-tube manifolds, larger single exhaust, HO 1.21 2V Carburetor with enriched metering circuits = 180 HP @ 4200 RPM and 260 FT -LBF @ 2600 RPM Stock 351, cast iron manifolds, single exhaust, 2V 7200VV carburetor, = 145 HP @ 3200 RPM and 270 FT –LBF 1800 RPM HO 351, cast iron manifolds, “modified” camshaft, dual exhaust, Holley 2300 2V carburetor, = 165HP @ 3600 RPM and 285 FT –LBF 1800 RPM “I do not have the output numbers for the HO 351 4V truck version.”
For the money,Demon is hitting it out of the park right now.Installed a Mighty Demon on a friends S10 drag trk. a while back on a mild 402 BB,ran flawlessly.Read an article recently where a dyno shop,on the same eng,compared a Demon to a same sized $1400 Holley Winston Cup carb.There was only a 5hp diff. between the two & a Demon runs about $600.
Just keep in mind those are SAE net figures. The numbers the general hotrod guys toss around when comparing "size" would be gross HP numbers. Just comparing numbers from a std 1969 302 2 bbl motor will throw you, as this motor was rated at 205-210 hp
So, you're saying that based on those 2 builds.. a 4bbl carb swap is ALWAYS going to trump a free flowing exhaust in the level of restriction reduction? Need to remember that the stock intake manifold is also adding to the restriction and part of any gain found from the swap will be attributed to the 4bbl manifolds less restrictive design. The carb itself is not the engines worst enemy. In fact.. most everyone here running stock sized engines with even moderately sized cams would be hard pressed to see significant power loss when shutting off the vac secondaries completely with a stiff spring. I've also seen near 600 horsepower big blocks lose less than 50 horsepower on engine dynos when the secondaries are completely eliminated from the mix. Same deal with multi-carb setups too. The reality is this. Up to a point.. it's much easier for an engine to suck in air through restricted inlets than it is to push it out through a restricted exhaust pipe/s. That's why you rarely see class racing(even pure stocks allow duals) with single exhaust pipe restrictions. It's just too damned boring for anyone to want to watch or spend money on the development involved to make max power. The numbers just aren't there for everyone to enjoy. The biggest thing to remember is that a good or even decent exhaust can easily be tailored to "pull more fresh charge into an engine". Putting a larger carb onto an already restricted(such as one equipped with an old sub-200cfm muffler).. will not effectively counteract a poor flowing exhaust. Simple physics always apply.
I have a Weind stealth intake, Holly 600 cfm, with 2 1/2" with flow master 40 mufflers. With an otherwise stock 302 in my 72 Comet and I can say that it runs a lot better than the 2 barrell and single exhaust.
And the added beauty is that it can be finely tuned to get even better mileage than it did when it made 40 less horsepower. Course.. keeping your foot out of it gets somewhat tougher to do.
