a guy i know wants to buy the spread bore carberator off me for 125 bucks so im going to sell it. if i get a different carb will all my old linkage and stuff work? and what is the best stock cast iron intake to look for thats relatively easy to find? because if he takes the carb im looking for an intake an carb combo
My truck is a 1978 F150 like your engine, but my enginge is a 1972 429 2V converted to 4V via SCJ intake with port match and Hedman headers. 1. 1968-71 Timing chain set a must, to me. 2. Headers a must, again to me. 3. Intake change I would recomend if you are after good performance. I like the cast iron Scj, but a Cj spreadbore flange could work well and gives you the Q-Jet option, which can improve gas mileage, over alot of the Holleys, but not neccesarry all of them. If you like Aluminum, depending on combination of engine there are several to choose from. 4. Heads, If you want better performance than stock I would remove the exhaust humps for sure if your's still have them. If you go with the CJ/Scj intake portmatch the intake while there off, and change valve springs to match the cam you choose. I would stay pretty close to .500" lift with stock springs, but you may get by with a tad more, say .540" max, if you feel lucky. 5. Cam I would stay around 270 or less advertised duration, thats around 219 to 226 at .050 for most manufacturors. From what I have, seen, I look at the .050" duration specs, and ignore the advertised duration, because different companies measure the cam duration, at different lift heights, to determine duriation, IE .002" to .006" lift before they measure duration. 6. You may want to throw in a 2,200 Rpm convertor if you go with a 270ish cam, but not a must.
7. I like Holley 750 Double Pump carb, with the downleg boosters, not the stait ones, with the tube through the booster, and yes I have seen a few 750 with these boosters around, but they drink alot of gas. Holley makes or did make a Semi Spread Bore Square Flange carb with Ford Auto trans kickdown in both 650 and 750cfm with the emissions metering blocks that should improve mileage over the regular Double pumps, and they was a Double pump also. The Holley List #'S are 6708 and 6709, 650 and 750cfm, respectivily. The CJ cast iron with an old Endelbrock 895cfm Q-jet should work really well also, but you may have to hunt for a used one, as I don't believe they make them anymore? Once you get past this, very much, you are entering the world of Hot Rod and prices and driveabity as well as gas mileage start going crazy quickly.