mirageshepard Posted March 23, 2020 Report Share Posted March 23, 2020 I forgot about this till just recently, but years ago while talking to travis (tloof) he mentioned about a carb that would be ideal for my then engine although I don't remember which one but I'm sure it was for either the NAPZ 24 or the VG30E. The carb was off a Ford 390 FE though I'm not sure what year. I know there's way easier and better carb set ups for mentioned engines these days but because I've never toyed with one or even seen one modified to such a set up ... it's always intrigued me (when I remember it). These days I don't do very much or even wrench on much anymore due to health and financial situations. I do want to find that specific carb to toy with and rebuild and keep around for when I do get back into wrenching and find the specific engine to slap it on... or something similar. I would of asked travis (tloof) but have tried to make contact over the years but being he's among the living legends proving to be a busy man with desirable knowledge.... he's proved to be harder to find then a 10mm socket! My question is if anyone else knew about this specific carb for such a set up and is there a specific year/version I need to look for? Thanks in Advance! Quote Link to comment
datzenmike Posted March 23, 2020 Report Share Posted March 23, 2020 There were 350 and 500 cfm w2 bbls on the 390 Fords. Probably the 350 would be more than enough. 1 Quote Link to comment
Str8jacket Posted March 23, 2020 Report Share Posted March 23, 2020 A 390cfm 4 barrel vac sec would be better again than a 350 2b on either those engines. 😉 Quote Link to comment
Jesse C. Posted March 24, 2020 Report Share Posted March 24, 2020 what engine are you putting this on? A 390 CFM is too much for a VG30, and especially for a NAP Z A 350CFM or even a 38/38 Weber would be ideal for a VG and a Weber 32/36 would be fine for a NAP Z Quote Link to comment
datzenmike Posted March 24, 2020 Report Share Posted March 24, 2020 Way too big. Size and CFM. A 2.4 liter engine draws in 254 CFM of air at 6,000 rpms. Up to a point a larger carb is easier to suck air through and energy saved doing this is energy gained. If a 4 bbl a small 2.4 liter engine won't move enough air to pull the secondary open. If larger carbs make more power then LARGER carbs would make MORE power. I don't see anyone running 1180 hollys on an L20B. Quote Link to comment
mirageshepard Posted March 24, 2020 Author Report Share Posted March 24, 2020 To specify in case I wasn't clear the 390 I mentioned was the size of the engine... not the carb. The carb I'm referring to COMES on those engines... probably other applications as well Quote Link to comment
mirageshepard Posted March 24, 2020 Author Report Share Posted March 24, 2020 1 hour ago, datzenmike said: There were 350 and 500 cfm w2 bbls on the 390 Fords. Probably the 350 would be more than enough. Thanx! I was hoping you would chime in. I seen some specs when I did a quick search on those types of carbs and seen a few different ventury/jet sizes for that type of carb set up but I don't know enough to think "ok this and this is what I need to make this work on x engine " Quote Link to comment
Str8jacket Posted March 24, 2020 Report Share Posted March 24, 2020 A holley 350 has 1 1/2in primaries. A 390 has 1 7/16 primaries. If it doesnt need the secs they dont open. You have more tunabilty. Position it with the primaries furthest from the engine. A lot of the better performing v8s producing massive hp and maintaing drivability are using carbs 1.5 x the size they would have 20 years ago. 4 barrels work very well when set up correct, pretty much like all carbs. Quote Link to comment
datzenmike Posted March 24, 2020 Report Share Posted March 24, 2020 Why didn't car makers put 4 bbls on all their 4 cylinders???? Quote Link to comment
Str8jacket Posted March 24, 2020 Report Share Posted March 24, 2020 Probably due to expense. Why do so many people pull off the standard parts to fit aftermarket? Quote Link to comment
datzenmike Posted March 24, 2020 Report Share Posted March 24, 2020 They've been convinced that after market is faster/better and sometimes it is. Sometimes it's just shiny. Sometimes it's $30 per HP gained. A 2 liter engine at 6,000 RPMs uses about 211 cubic feet of air. That's 6K wrung out continuously for one minute. No one does that. I think the 32/36 is about 270 CFM and that's a bit more than needed but a larger carburetor is easier to pull air through so it doesn't have to work as hard pulling. There's a small efficiency gain here. If larger carbs made you go faster we'd all get larger and larger and still larger carburetors, until we have Holly 750 double pumpers on our L20Bs. No one does, because it doesn't work that way. An L20B has a 30/34 Hitachi and is a compromise for drive-ability, mileage and performance. If mileage and drive ability weren't so important a 32/36 would be better but not a carburetor capable of 500 CFM. A 390 Ford engine can use a 500 CFM because it's over 3 times the displacement. 1 Quote Link to comment
Str8jacket Posted March 24, 2020 Report Share Posted March 24, 2020 1 hour ago, datzenmike said: A 390 Ford engine can use a 500 CFM because it's over 3 times the displacement. And would be a case where i would say you could use 2bl 500 holley. (I wouldnt though). I would not and did not recommend using it on a 2.4 4cyl. The primary barrels on a 390 holley are 11% smaller than a 350 holley (and a 38 /38 weber). And 27% smaller than a 500 holley. Like i said, secondaries are not used until vacuum is high enough to open them, even then they dont necessarily open all the way. CFM ratings on 2 to 4 barrel holleys are measured differently anyway. Quote Link to comment
datzenmike Posted March 24, 2020 Report Share Posted March 24, 2020 I've heard this also. Well throw CFM away and go just by displacement. A carburetor that is sized for the application is best. To work properly there has to be enough air passing through it to cause a vacuum at the venturi to suck gas in. The 2 bbl Hitachi with vacuum secondary. Opens only when capable of using it. Quote Link to comment
Lockleaf Posted March 24, 2020 Report Share Posted March 24, 2020 Mazda put 4 barrel carbs on the rotary. The 4 barrel Nikki carbs are freaking sweet. Maybe look to those. Quote Link to comment
mirageshepard Posted March 25, 2020 Author Report Share Posted March 25, 2020 19 hours ago, Lockleaf said: Mazda put 4 barrel carbs on the rotary. The 4 barrel Nikki carbs are freaking sweet. Maybe look to those. A buddy has played with those as well as a few others and he's now putting a Weber on his rotary. The carb I mentioned was just something I want to play with and test it out on a 3.0 or smaller engine for tits and pickles. I can't start a massive project for this at moment because every time I do... my health and financial situations cause me to sell or give away the project. Hopefully this I can tinker with inside till I find something to put it on ... eventually.... Quote Link to comment
datzenmike Posted March 25, 2020 Report Share Posted March 25, 2020 19 hours ago, Lockleaf said: Mazda put 4 barrel carbs on the rotary. The 4 barrel Nikki carbs are freaking sweet. Maybe look to those. They also rev to the moon and devour huge amounts of air. 1 Quote Link to comment
mirageshepard Posted March 26, 2020 Author Report Share Posted March 26, 2020 10 hours ago, datzenmike said: They also rev to the moon and devour huge amounts of air. My buddy also mentioned that the nikki carbs he's worked with are finicky... main reason he doesn't screw with them anymore Quote Link to comment
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