Reply With QuoteI'm interested to see what people say it is. I've got a 455 that wouldn't pass 3500 rpm..
Todd
Here's the story, boat belongs to a buddy of mine, just bought it, but appearently is only hopping up to 3000 revs.
Details...16.5' Baja, 350 Olds, 2bbl carb 2 bbl intake, log manifolds, HEI ignition, Berk pump, and I would guess an A impeller. I should be able to look at it this weekend, and tell you a little more. According to the test drive, there didn't seem to be any engine increase from 3/4 throttle to wide open, but testing conditions were not the greatest (choppy waters).
My inexpensive suggestions were to upgrade the manifold and carb to a 4 bbl to increase the airflow and maybe even go with a B cut impeller. I'm know alot more could be gained by getting into the engine itself, but that might be later.
He will be reading this -so please be nice. Hell, he's a jetter now too.
I'm interested to see what people say it is. I've got a 455 that wouldn't pass 3500 rpm..
Todd
It has to be a carb, air or timing issue. My mild 455 spins at 4800, so it shouldn't be too hard to get a little more out of this 350. I'm thinking about getting an adapter to run a 4 bbl on a 2 bbl intake to see if that gains anything.
Wet Dream:
Here's the story, boat belongs to a buddy of mine, just bought it, but appearently is only hopping up to 3000 revs.
Details...16.5' Baja, 350 Olds, 2bbl carb 2 bbl intake, log manifolds, HEI ignition, Berk pump, and I would guess an A impeller. I should be able to look at it this weekend, and tell you a little more. According to the test drive, there didn't seem to be any engine increase from 3/4 throttle to wide open, but testing conditions were not the greatest (choppy waters).
My inexpensive suggestions were to upgrade the manifold and carb to a 4 bbl to increase the airflow and maybe even go with a B cut impeller. I'm know alot more could be gained by getting into the engine itself, but that might be later.
He will be reading this -so please be nice. Hell, he's a jetter now too.Well I suppose you could start with a simple dual plane intake and a simple 650 vacuum secondary carburetor. It would be the best bang for the buck considering your set-up. Ensure that a good tune-up has been performed; spark plugs, cap/rotor, timing etc.
Once you get a new air/fuel system such as carb and intake, you might be surprised on what she will do for ya.
If you wanted something a little more aggressive, add a double pumper 650 in place of that vacuum secondary. You will get a better throttle response but in turn your gas mileage will suffer. If gas mileage is your concern, then sell the boat, because jets are the worst!
-Ty
Look at your Air filter (spark arrestor) clean the holy cr*p out of it! Most people don't everpay attention to them. They get dirty just like other filters & will dramaticly cut your RPM since the engine can't get the air it needs. You can do all the upgrades you want but if the basics aren't done first they will never matter!
Good Luck
With a factory equiped 2 barrel, I'm guessing that this particular 350 Olds, is probalby putting out somewhere in the 250-270hp category when orriginally installed. That kind of HP isn't going to spin an A impeller very fast at all, especially figuring that if those HP numbers are close to right, their probably being made around 4k RPM. The bottom line, if it's an A impeller, you'd probably want to cut down to a B to let the motor spin up a little bit. In a 16.5' boat, you could even cut it a little lower if the need arose.
Looking away from the pump/motor setup. The list of things you should check is pretty simple.
Check timing at idle, and WOT. You should be running around 32 degrees of advance at WOT. Since it's an HEI in a boat(not typical factory equipment) you might find something lower for your total advance. Since you can currently only spin to 3kRPM, you need to ensure that your advance all comes in before 3k.
Once you have verified the integrity and functionality of the distributor, put a strobe(timing light) all each of the plug wires while under load and make sure you aren't dropping any cylinders as the RPM increases.
Do a plug check where you run the boat at 3k RPM, then slow down just enough to be in control before turning the key off. Coast to a stop, then pull the corner plugs. 1,7,2,8 and check your mixture. Too rich will usually rob you of RPM. Adjust mixture accordingly.
Oh yeah and just for S**ts and giggles, make sure the throttle plates open all the way when the pedal is to the floor. There could be something wrong with the linkage (especially if its the Morse combo deal with throttle and gate on the same lever) which is precluding you from allowing enough air into the motor to pull more RPM.
It would be good to know all of this for certain before spending money on changes which might be undermined by a pre-existing condition in another system.
The only way to check the impeller size is by pulling the bowl and checking the small diameter against the Berk Impeller Charts Hopefully the boat has a JE/F pump so the bowl is outside the transom and easily removed. You can also check the tag on the pump where the serial number is located over the thrust bearing housing. It will give the model and impeller initially installed in the pump. The impeller could have been changed, but its another place to look. The info would look like JC-A, or JE-B, or JE-A, with the first two letters designating the pump model, and the hyphenated third letter being the impeller cut.
Once you go through a basic check on the state of tune for the motor and get info on the current impeller, the suggestions given on this thread can be a lot more meaningful and accurate.
Good luck and let us know what you find out,
Chris
Set timing to 36* total. Some guys lock the distributor out and use a start retard, it adds alot more throttle response and low end. I wouldn't bother with trying to put a 4bbl adapter on that intake. If he plans on keeping the 2bbl setup, flatbroke has the tuneup down.
Do you know what number the cylinder heads are, or what the block casting number is?
I wouldn't suggest a double pumper unless the engine was built up. Double pumpers have a rich idle circuit, they are not meant for mild engines. A vacuum secondary carb is a better choice for a mild engine.
http://www.realoldspower.com
Bill, I have a real nice Holley marine 650 cfm. $125
rktpwrd:
Set timing to 36* total. Some guys lock the distributor out and use a start retard, it adds alot more throttle response and low end. I wouldn't bother with trying to put a 4bbl adapter on that intake. If he plans on keeping the 2bbl setup, flatbroke has the tuneup down.
Do you know what number the cylinder heads are, or what the block casting number is?
I wouldn't suggest a double pumper unless the engine was built up. Double pumpers have a rich idle circuit, they are not meant for mild engines. A vacuum secondary carb is a better choice for a mild engine.
http://www.realoldspower.comNot to rein on your parade, but the 650 Double pumper out of the box is rich, yes, but it can be de-tuned with some minor tweaking so his motor would respond to this.
Just my 0.02
Well I got a way better idea that don`t cost jack! Check the fuel filter first! If boat sat up, siphon fuel outa da tanks! Put in a set of plugs. Get an intake, block off heat risers and smack on a 650, but go with the vacuum secondaries cause this baby don`t sound like its made for speed rather bang for buck. I think you should styay that way.
Gotta love those bench racing fags!
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