I've got a problem with my flathead and I hope I can get a little advice. I know this could be alot of different things so I'll lay out what I'm running and let ya'll have at it. I've got a 53 Merc flathead bored .030over. hollow lifters. two holley 94s. stock otherwise. Mallory distributor. 12 volts running an alternator. The carbs are the large diameter holleys with the spray bars out of truck carbs. Charlie Price at vintage speed set this up for me and no, I can't recommend him. Poorly machined leaky carbs with stripped bolt holes and I dented top. (none of this should factor into my problem though) The deal is this. When I was running the stock manifold and carb, it ran great. Not real powerful obviously but runs good nonetheless. When I added the Fenton Manifold and two carbs, I started to bog down on me when I floor it. Idling is fine and cruising low rpms is fine. When I punch it it bogs down. I removed the 2x2 setup and put one of Charlies carbs on the stock manifold and it still does it, just not as bad. Only when I really mash it in second gear. I think I've ruled out timing. I've got a new coil. I'm thinking it is jetted wrong. If I remember correctly, they have size 48 jets. Does anybody else run a similar setup and how do you have yours jetted. Am I getting too much gas are is it starving. Oh, one more thing. It's been a few years since I worked on this motor, but I think at one time I jetted it up a hair and it got worse. I can't really remember though. Any help would be appreciated.
I've got a merc flathead with a 2 duece 94 set-up on an offy intake. I also have a heavy duty electic fuel pump 'cause the original just wasn't cutting it and it is also a way to help minimize vapor lock. Don't know if your running stock or an electric. My problem was too much fuel going to the carbs and it was bogging like it sounds like yours is. A $20 regulator from O'Riley's and a new air cleaner set up fixed the problem 45 minutes and a case of beer later. Good luck.
First, do the fuel pressure regulator, it's real easy to over power the floats. Then check the econimizer valves in the Holleys, They could be leaking or not opening at the right vacuum level.
I forgot to mention I'm running the carbs with blocked power valves, and I'm using a mallory distributor. I'll check the fuel first. I don't have a guage on it but I'll start there. I was checking some posts and a few people have said the Mallory uses the wrong advance curve. Maybe need to adjust there also?
I started thinking and I may be wrong about the power valves being blocked. I read where current thinking is to use smaller power valves on 2x2 setups. I'll check tomorrow when I get to the garage to see what the heck is on those carbs. I'ts been a long time since I worked on em.
Power valves: They are not sizes, as they do not meter the gas except as 0n-off valve; numbers are vac level at which valve opens, metering is at drilled restrictions, all just like Holley 4 barrels. Smaller number is usually need to keep valve from opening too late. If you actually have blocked off valves, setup cannot be made to run right at all throttle openings--requirements for part and full throttle are completely different.
Read some of my experiences. Putting the rebuilt carb on the stock manifold and having problem should point you in a good direction. Try the other carb on there. May not apply but I went through some steps to eliminate the problem here. http://jalopyjournal.com/forum/showthread.php?t=136751&highlight=cutting
Yes--definitely sort out both carbs on the single manifold. I'd start by taking them apart and finding out WTH Charley actually put in there...a carb that has been messed with by someone other than yourself is like a box of chocolates that has been left out in a locker room full of monkeys... and closely check fit of PV to the casting--most are 4 barrel ones that need modification to fit. If the carbs don't run right alone, they sure as hell aren't going to work as a pair!
I went over to the garage today to find out what I actually had. Turns out I'm running 5.5 power valves. An article I read by Ron Ceridino said that he likes to start with 3.5 to 4.5 power valves and go from there. I also checked and I'm running .048 jets. Could be my advance curve isn't right for the setup. I'll work with new power valves first and then check the settings on the Unilite. Any other suggestions?? Anybody have cam suggestions for this motor. Nothing too hot obviously cause I don't wanna change much. I'm gonna do a bit of a porting job when I pull the motor next but thats about all.
Just thought about something while I'm sitting here fishing for an answer. You would figure after 70plus years of the flathead being run in every concievable fashion, there would be some sort of consensus or some sorta recipe as to how to put together a simple, slightly hopped up, clean running flathead. How is it that guys are still arguing over the best ignition system to run on this motor. I suppose that is part of the allure. Voodoo instead of science. There are plenty books out there that seem to have a good basic recipe but we still dabate round and round as to what really works. I guess it's like all the guys I know arguing about how to cook a good pot of Seafood Gumbo. One of the simplest dishes around but everybody has their own way in the kitchen and dammit, their gumbo is the best. Gotta love it. A very confused Layne in Louisiana
Definite second best distributor for a '49-53: ANYTHING except the stocker. First place: Major dogfight!
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