SoCal Jet Boats
Tech Talk => Engine Mechanical / Electrical => Topic started by: beerjet on April 30, 2007, 10:05:57 PM
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Well as some of you know . My lake boat turned race boat doesnt keep up on the race course . I have no idea what is in the engine either since I bought it from a dealer here locally 5 or so years ago and since then it's gotten a new timing chain (since the old one was as loose as a bicycle chain) push rods, balancer , carb , 2 intake manifolds , converted the distributor from points to electronic .
First off , anyone recomend a cam for the circles .
second , I was hoping to cut cost by reusing the crank and rods. Buying all new valve train and of course all the machine work to both block and heads then just goin with new pistons and higher compression .
Third would be, doin a 496 . More money . More parts . Need more time . Maybe a new top end package of my choice . Almost guarranteed to push me into the 80's .
So basically I need your realistic input on both , and yes money is an object . Race gas was factored in and with the compression I want it a go.
Am I being a cheap ass or is the first possible.
-beerjet-
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Yea you're being a cheap asss, but I'm a cheaper asss. Wait a minute I have to think about what I just typed. ::)
My carb guy (who's been into every form of racing for 50 years - usually connected to the winner's circle recomends Schneider cams for jet boats. They have a JB3 and a JB4 cam, which one you pick is based on your compression. But wait a minute, I think I recall you telling me you had a roller cam in your engine. Hmmmm. ???
Keep that loose Cheby the way it is and bolt a blower on it. It can handle the blower because of all that blow-by your pistons have. ;D
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hey bj it cost money to go fast how fast do you want to go ??? if it were mine screw the 496 its all torque go with the468 its cheaper and builds just as much power, torque will come with the power you want to go with a 1/4 stile cam lots of duration and lift get the power quich not have to work up to it put and msd 6al in it and a single plane manifold and a good holley for the crank and rods get ahold of castillos this guy rocks from stock to billet he can help and he understands the budget for head work one of two people out this way mendello or my guy wayne either way kick ass but not cheap i wouldnt run anything that is supposed to be for a jet boat cam wise mine is a one of howerd cam full roller not cheap but does the trick get the cam then work on the compression becouse thats the easy part just my thoughts
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hey bj it cost money to go fast how fast do you want to go ??? if it were mine screw the 496 its all torque go with the468 its cheaper and builds just as much power, torque will come with the power you want to go with a 1/4 stile cam lots of duration and lift get the power quich not have to work up to it put and msd 6al in it and a single plane manifold and a good holley for the crank and rods get ahold of castillos this guy rocks from stock to billet he can help and he understands the budget for head work one of two people out this way mendello or my guy wayne either way kick ass but not cheap i wouldnt run anything that is supposed to be for a jet boat cam wise mine is a one of howerd cam full roller not cheap but does the trick get the cam then work on the compression becouse thats the easy part just my thoughts
Money is no object said what ??? ;D
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you can throw some more $$$$$$$$$$ at this engine or just do the 496 and be done. however you said you are on a the cheap plan, did you figure out the oil pressure deal?? since its not knocking i think you should tear it down and see what you are working with and go from there. parts are cheep for the chebby rebuild what you have put some new pistons and a good balance and new cam done for what 1500. now how much is that 496 stroker kit. hmmmmm, easy hp just my .02
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As a newbie to this site I'm going to start giving input slowly, but I think this is a good place to start.
I would rebuild the bottom end with quality parts, match the cam/compression and spend as much as I could afford to have the cylinder heads ported by someone that knows how to do it correctly. Anybody can bolt together a good engine with over the counter performance parts, but to make serious gains the cylinder heads are the best place to start. ;D
Keith
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just because you got big cubic inches donsent always mean lots of horse pwr try building the motor to turn higher rpms the horse pwr gains will follow
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just because you got big cubic inches donsent always mean lots of horse pwr try building the motor to turn higher rpms the horse pwr gains will follow
why not run a small block then?
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OK. Take the engine apart and inspect and measure all the parts. See what's in there, maybe your engine has a forged crank in it ;D If it needs to be bored out then bore it out, if it don't need to be bored leave it. Bigger cam. See what's been done to the heads, are they rectangle port? etc... HP requires air ;D If you want any kind of real HP your Chevrolet is going to need rectanglular port heads ;) Your intake manifold is a good one, same with your carb, get MSD box if you can afford it - if you don't have it already...
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The heads are oval ports that already have some serious port work done and that is my main area of concern . I realize that the power is made in the cylinder heads so I'll see where that takes me . Thanks for all the input guys . Anything else you might have left out.
-beerjet-
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I don't know if your engine's heads are open or closed chamber but every pro engine builder I've talked to or one of my driends have talked to - they all said the BBC needs the rectanglular ports or it will be limited by the heads. I'm talking about serious high end engine builders. An engine is an air pump and the BBC oval port heads are limiting the air intake. You can have oval port and rectangular port BBC heads, you also can have closed chamber or open chamber, closed chamber = generally higher compression and somewhat restricted, open chamber = generally lower compression and lots of flow and lots of room to port.
I'm willing to bet you could get a pretty good penny for those heads you got (especially with a fresh rebuild) and for a few hundred more you have the best. There's a reputable shop here that has/had a pair of rect. port open chamber fully rebuilt for $900.00. You can find aluminum for around $1400.00 Like I said from what I was told over and over again was you can't make serious power with a oval port head and that the oval port heads weren't worth porting. The probable (?) exception is probably aftermarket aluminum oval port heads..02
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you could run a small block. thats when you look to strock the motor because a 454 ci small block wiil out rev a 454 big block.
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Best case senario is I go with the 308 or 310cc pro1 darts top end package . Pray for me people .
-beerjet-
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for the same price I am building a 383 stroker all forged internals and aluminum heads vs. a cast internals and cast iron BB. I also saved 260 pounds over the BB. Since I have forged crank,H-beams and forged pistons and a little money left over i am also throwing a 200 shot of nitrous. Desktop dyno estimated around 500-550 HP at 6000rpm without spray :-\ Hopefully thats accurate. Also its a high reving broad torque curve.
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Best case senario is I go with the 308 or 310cc pro1 darts top end package . Pray for me people .
-beerjet-
just do it or i'll get u a subscription
(https://www.socaljetboats.com/index.php?action=dlattach;topic=681.0;attach=1777;image)
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you could run a small block. thats when you look to strock the motor because a 454 ci small block wiil out rev a 454 big block.
He doesn't have a Ford. ???