carby set up for a 350 chev
Submitted by Faulkner Family on Sun, 2010-05-30 14:16
i was talking to a bloke the other day about the problem i have with a flat spot in the carby.i mentioned i had a 350 holly on it and he said straight away that that was the problem as the 350 holly isnt big enough for the 350 chev. he said if i went for something like the 650 holly 4 barrel i would get more power out of the motor as the current and wouldnt need to run at as higher revs to get the same speed .carby isnt allowing enough fuel through to feed the motor along with not enough air getting in to mix. Anyone else had the same probs and is it worth spending the $ to upgrade to the 4 barrel. i have lined up a manifold for it at the right price if i go ahead with the upgrade
____________________________________________________________________________
RUSS and SANDY. A family that fishes together stays together
81macca
Posts: 270
Date Joined: 02/07/09
The 350 holley is probaliy
The 350 holley is probaliy too small but they are more reliable than a four barrel and easier to repaire. There is a 500 two barrel that will allow more air into your engine if you can get your hands on one. The amount of different power valves and jets available for your holley is massive pretty sure you could make the 350 work well as the boat is going to be working at pretty low revs. If you were to change the carby I would look at what other carbys are available other than a holley, good for the street but too tempramental for a boat and do leak fuel (not good for a boat) when they get older.
I actually fish.
MarineDoctor
Posts: 21
Date Joined: 14/04/10
The older 5.7 mercruisers
The older 5.7 mercruisers only had a two barrel carby and they worked fine
dodgy
Posts: 4577
Date Joined: 01/02/10
I second the 500 Holley. Ive
I second the 500 Holley. Ive found that a smaller carb will sometimes make more torque lower down in the rev range. Lose a bit up top but your probably not looking at running to 6 grand all day anyway.
Im running a 650 double pump on my Chev. Scary how effective they are at throwing down the fuel.
Does anyone know where the love of god goes, when the waves turn the minutes to hours?
CrazyDhufish
Posts: 15
Date Joined: 06/05/10
Sorry I might be a bit daft
But I would have thought that unless you change the gearing the motor will still have to run at the same revs to get the same speed ??
Holley 350's were great for economy on 302 and 308's, a 500 will give you more air/fuel
but I would have thought on a boat that unless you wanted more take off power (maybe for skiing) you will just be wasting you money
Then again I am no marine mechanic.
Faulkner Family
Posts: 18026
Date Joined: 11/03/08
my understanding was you get
my understanding was you get more fuel through so your not needing to push the motor as hard to get the same power.also removing the flat spot as the motor is no longer starving for fuel. Thats what this bloke told me , he has been working on chev motors for ages as well he is a qualified mechanic as well as a friend.so im thinking he might have some clue on it. This was more a question about the 650 holly or similar
RUSS and SANDY. A family that fishes together stays together
paul landphobic
Posts: 71
Date Joined: 26/10/09
500 holley
500 holley are ok ,but if it still needs more fuel if it leans out you can always rejet the carbie .by removing the front cover bowl it is pretty ezy to change the jets
Rod P
Posts: 725
Date Joined: 20/05/08
I actually removed my old
I actually removed my old hollies when i changed motors over (actually i think i still have them out the back) and refitted Rochester carbies. Honestly better economy all round. Mostly because they have a saller first stage.
Indiana
Posts: 307
Date Joined: 15/12/09
Rod P on the money !
Holley's are over rated !
Ski boat I had would not do the goods on Holley's at all.
Fitted a Rochchester and it cured all the problems and provided far better economy.
" IF YOUR NOT GOING TO EAT IT ......PUT IT BACK WHERE YOU CAUGHT IT"
Faulkner Family
Posts: 18026
Date Joined: 11/03/08
are the rochchester a 4
are the rochchester a 4 barrel or 2 ?. worth a thought
RUSS and SANDY. A family that fishes together stays together
Rod P
Posts: 725
Date Joined: 20/05/08
4 barrel i think but much
4 barrel i think but much smaller on the first stage. Sunny would have a better idea. I just did what i was told to by my mechanic..
Indiana
Posts: 307
Date Joined: 15/12/09
4 Barrel
Yes Russ , Rochcester's are 4 barrel.
You should be able to get an adaptor plate from your 2 barrel Holley to a 4 barrel
mount.
" IF YOUR NOT GOING TO EAT IT ......PUT IT BACK WHERE YOU CAUGHT IT"