issues after engine swap

[jcdubbu]

Recently finished a very frustrating engine swap on a 78 seaswirl. Went from stock 305 to a 350. To my surprise after connecting the water hose and a little adjustment on the timing she fired right up and purred like a kitten. Problem is when she gets up to 3000rpms she seems to miss a bit and act like it she is starving for fuel. Mechanic said he thinks it's starving for air and the carb and intake need replacing because they were the orignals from the 305. Carb was gone thru and adjusted. Using fresh gas from an auxiliary tank. He also said I need a new rotor. Im currently running a Mallory YL624JV distributor and it's only a few years old. Any ideas on some possible issues to check? TIA

 

[Scott Danforth]

change your cap and rotor.

 

[Howard Sterndrive]

Is it a 2 barrel or 4 barrel carb?

starving for air? no. Might be starving for fuel, but not just as a result of the new displacement.
The fuel requirements for getting on plane with your boat are no different between a 305 and a 350 until you open the throttle wide. Your boat takes a certain amount of fuel to make the HP required to get it on plane. If fuel mixture were the issue, you might hear some lean pops or backfires and you could simply throttle up slightly slower and the carb would know no difference from the old engine. (sorta)

I would triple check firing order and timing, look for vacuum leaks, make sure choke is opening fully, general linkage and visual inspection. .

 

[jcdubbu]

It is a 2 barrel carb and it doesn't backfire or pop...More like its bogging down. I will replace rotor and cap and check. As far as vac leaks I would think it would idle inconsistent but like I previously mentioned it runs beautifully until it gets to 3000rpms. I will double check for any air leaks. If anyone has any other suggestions please let me know. Thanks

 

[Scott Danforth]

Sounds like the carb has dirt in it if it bogs down at 3000 RPM.

 

[Howard Sterndrive]

2 barrel may be an issue. That 5.7 may need more than that carb can give it. I think there *may* have been a 2 barrel marine 350, but 99% of them are 4V.

 

[jcdubbu]

Anyone know where I can get a new cap and rotor for a Mallory yl624jv distributor? Having troubles locating one?

 

[Wildman4x4]

http://www.jegs.com/p/Mallory/Mallory-Distributor-Caps-Rotors-and-Accessories/748653/10002/-1