Carb questions

[Patchman]

I would throw some more timing at it just to see if it likes it.  I'm betting it would like 38-39 total.

While it is possible it might like that much timing, I would be very carefull to monitor the motor closely for signs of detonation.  IMO (which is almost worthless compared to Tim's mechanical knowledge) that sounds like a lot of timing for a basically stock 350 running on 90-93 octane fuel under the constant load found on an outdrive type boat. Mercruiser recommends 32 degrees total maximum if you go by the chart and add intitial. I ran 10 degree initial and about 32 total on the 350 in my Glastron with 93 octane and it seemed to like it & I felt pretty safe. The problem with an enclosed engine compartment is you can't really hear a problem if it's knocking a little until it's too late so just pay attention if you kick the timing up that much.

Disturbed is thinking it's time for that 350 to go down the track! :smile16: :smile16: :smile16:

 

[Disturbed]

I would throw some more timing at it just to see if it likes it.  I'm betting it would like 38-39 total.

While it is possible it might like that much timing, I would be very carefull to monitor the motor closely for signs of detonation.  IMO (which is almost worthless compared to Tim's mechanical knowledge) that sounds like a lot of timing for a basically stock 350 running on 90-93 octane fuel under the constant load found on an outdrive type boat. Mercruiser recommends 32 degrees total maximum if you go by the chart and add intitial. I ran 10 degree initial and about 32 total on the 350 in my Glastron with 93 octane and it seemed to like it & I felt pretty safe. The problem with an enclosed engine compartment is you can't really hear a problem if it's knocking a little until it's too late so just pay attention if you kick the timing up that much.

Disturbed is thinking it's time for that 350 to go down the track! :smile16: :smile16: :smile16:

:smile14:

36 degrees shouldn't hurt anything if you're running 93 octane.  Are those Vortec heads aluminum?  Most are right?  As a general rule, you can use aluminum heads and get away with another 1. of compression before detonation.  I would put it on 36 and see if it made any improvement.  If it does, see how much more it will take.  (you might want to get some 100LL for safety's sake)  Just keep in mind that the more timing you throw at it, the harder it will be to turn over and start.  Once you find out where the max performance is at, back off a couple degrees and adjust fuel as necessary to eliminate the risk of detonation.

* Disclaimer: This is what I would do.  Not suggesting that anyone should do anything that I would do.  :smile30:

 

[Patchman]

I don't think SBC can handle all that! Sounds like you are thinking of SBF! :evil:

 

[customtouch]

I would throw some more timing at it just to see if it likes it.  I'm betting it would like 38-39 total.

While it is possible it might like that much timing, I would be very carefull to monitor the motor closely for signs of detonation.  IMO (which is almost worthless compared to Tim's mechanical knowledge) that sounds like a lot of timing for a basically stock 350 running on 90-93 octane fuel under the constant load found on an outdrive type boat. Mercruiser recommends 32 degrees total maximum if you go by the chart and add intitial. I ran 10 degree initial and about 32 total on the 350 in my Glastron with 93 octane and it seemed to like it & I felt pretty safe. The problem with an enclosed engine compartment is you can't really hear a problem if it's knocking a little until it's too late so just pay attention if you kick the timing up that much.

Disturbed is thinking it's time for that 350 to go down the track! :smile16: :smile16: :smile16:

I think so!!  A true racers attitude, Trying to squeeze that last tenth of a second out of the family station wagon!!!  LOL!! :grin:

 

[jimmyray0682]

Right now mine are aluminum factory pull offs. But this winter a set of trick flows are gonna find there way on it.

 

[Patchman]

Right now mine are aluminum factory pull offs. But this winter a set of trick flows are gonna find there way on it.

Nice! :smile17:

 

[jimmyray0682]

Another question. I just bought a set of world product heads. Gonna have them milled down to 60cc combustion chambers and go with an lt4 hot cam. The guy I bought my heads from threw in a victory Jr intake. I have a performer rpm. Which one should I go back with? I know the dual plane will give me low end. But will the bump in flow and compression compensate for the single plane?

 

[Patchman]

With it being an I/o I would think the dual plane is still probably the better of the two. It won't do you much good to put an intake that favors high RPM. You probably won't reach that high with your hull and prop combination. If you are willing to change the prop, you can probably get it there. But as with anything you will loose out on the other end. :smile30:

 

[Disturbed]

With it being an I/o I would think the dual plane is still probably the better of the two. It won't do you much good to put an intake that favors high RPM. You probably won't reach that high with your hull and prop combination. If you are willing to change the prop, you can probably get it there. But as with anything you will loose out on the other end. :smile30:

Sounds plausible to me.  :smile30:

 

[FL350]

I run into this all the time with customers. Your dual plane performer is the way to go!  It will flow excellent with those heads and give you way better performance than the victor in your application. Also don't forget if you run a carb spacer, get the open one.  A common mistake I see is when people put those 4 holers in there, and that defeats the purpose. CSR makes a nice billet 1 1/2 that does great on a 4150 carb.

 

[jimmyray0682]

That's kinda what I was thinking. The dude I bought the heads from had it laying around and threw it in. So got a victory Jr intake and some 1.5 roller rockers for sale now.