Want to move from 781's to Aluminum
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Want to move from 781's to Aluminum

  1. #1
    Senior Member flatwater's Avatar
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    Default Want to move from 781's to Aluminum

    I'm sure this has been beat to death around here but... I want to get rid of my 781's and bolt on a lighter pair of heads. Boat is a 73 stevens v drive with a 454. Used for skiing only so just looking to lighten it up some (sounds like about 80lbs) from the cast to the aluminum. I have a few quesitons...

    Would I be able to reuse any of my gear off the old heads if I got a set of bare aluminum heads? Springs/valves etc, or will they all be differn't?

    And yes... cost is a factor... best bang for the buck heads that are on the market currently?

    Cam in the motor is hydraulic flat tappet.

    Any place I can find good used heads?

    If you need more info let me know..... don't mean to open a can of worms

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    I would ask Cstraub to give you a quote on a top end package...then compare it to something used, you might be a little closer than you might think.

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    Some guy obnoxious001's Avatar
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    Quote Originally Posted by flatwater View Post

    Would I be able to reuse any of my gear off the old heads if I got a set of bare aluminum heads? Springs/valves etc, or will they all be differn't?

    And yes... cost is a factor... best bang for the buck heads that are on the market currently?
    I think you will find that almost all of the aluminum heads that you may buy will use 11/32 valves, and originals in the 781's would have been 3/8" stems. Springs may or may not be able to be used, depending on diameter and installed height, but why put a fresh set of heads together with old springs?

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    AFR265, Dart 275, Brodix 270 or a set of take ZZ502 heads, Rovals, is what you need to look for.
    Chris Straub
    Straub Technologies

    3HP is an A$$ Whooping!!! JW

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    Senior Member flatwater's Avatar
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    Quote Originally Posted by cstraub View Post
    AFR265, Dart 275, Brodix 270 or a set of take ZZ502 heads, Rovals, is what you need to look for.
    Thanks for the feedback guys. Thanks Chris, I talked to you before about my chevelle on the team chevelle forums. Seems like I got my self into a tug of war between my car and my boat (both having big blocks that need some performance added). Just playing round with one is pricy enough, let alone two of them. I could put 2 pairs of brodix 270's to work very quick, however explaining the visa charge to my wife would be a whole other story.

    (this would be a great time for someone to chime in telling me they have a pair collecting dust in their garage that they want to get rid of)

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    Senior Member TNYoungblood's Avatar
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    There is nothing wrong with 781s. If this is just a river boat I wouldn't worry about the weight issue, but that is just me. If it ain't broke, don't fix it.

    Now if your lookin for more performance than a new top end would be the way to go. But then your talkin Heads, cam, lifters, and push rods. $$$$$$$$$

    I'd keep on skiing and enjoying the boat as is until upgrades are a must.

    JMO
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    Senior Member Lildave's Avatar
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    ^^^What he said! Don't worry about that 80lbs! Spend that money on beer and gas!

    If you are highly concerned about weight and you are going to stay stockish HP, I would put an aluminum LS1 or LS2 in it and sell the BBC to recoup some money....saving about 300lbs.

    How much is a mid grade set of BBC heads with all costs involved? (Heads, gaskets, bolts, pushrods, etc)...... $2500? $3000?

  10. #8
    Senior Member flatwater's Avatar
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    Quote Originally Posted by TNYoungblood View Post
    There is nothing wrong with 781s. If this is just a river boat I wouldn't worry about the weight issue, but that is just me. If it ain't broke, don't fix it.

    Now if your lookin for more performance than a new top end would be the way to go. But then your talkin Heads, cam, lifters, and push rods. $$$$$$$$$

    I'd keep on skiing and enjoying the boat as is until upgrades are a must.

    JMO
    I agree with you if it aint broke don't fix it....but it's all weight that I'm trying to get rid of. I have even thougt about running a small block, but I'm not that desperate.

    When I'm skiing behind he boat (only the wife driving) and running on the bottom 1/4 tanks of fuel, it's near perfect for weight.

    If I fill the tanks and have another person or two (and that's often) the wake will double in size (thus being hard on the ol knees).

    We totally enjoy the boat, just seeing my options for getting the ol girl a bit lighter.


    Quote Originally Posted by Lildave View Post
    ^^^What he said! Don't worry about that 80lbs! Spend that money on beer and gas!

    If you are highly concerned about weight and you are going to stay stockish HP, I would put an aluminum LS1 or LS2 in it and sell the BBC to recoup some money....saving about 300lbs.

    How much is a mid grade set of BBC heads with all costs involved? (Heads, gaskets, bolts, pushrods, etc)...... $2500? $3000?
    You may have a valid option here. The LS1 is a 5.7 and the LS2 is a 6.0 correct? I guess the 6.0 is still considered a small block? I haven't played with any 6.0's. I'll keep my eye open for an aluminum deal. I'm ok with giving a bit of HP for some weight savings, but going to a small block is a whole nother story. Thanks for the tip!
    Last edited by flatwater; 04-15-2014 at 05:17 AM.

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    Senior Member TNYoungblood's Avatar
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    Quote Originally Posted by flatwater View Post
    I agree with you if it aint broke don't fix it....but it's all weight that I'm trying to get rid of. I have even thougt about running a small block, but I'm not that desperate.

    When I'm skiing behind he boat (only the wife driving) and running on the bottom 1/4 tanks of fuel, it's near perfect for weight.

    If I fill the tanks and have another person or two (and that's often) the wake will double in size (thus being hard on the ol knees).

    We totally enjoy the boat, just seeing my options for getting the ol girl a bit lighter.




    You may have a valid option here. The LS1 is a 5.7 and the LS2 is a 6.0 correct? I guess the 6.0 is still considered a small block? I haven't played with any 6.0's. I'll keep my eye open for an aluminum deal. I'm ok with giving a bit of HP for some weight savings, but going to a small block is a whole nother story. Thanks for the tip!


    I don't see going to a Aluminum set of heads makin that much difference, might be wrong

    There are a set of Brand new Aluminum BowTie heads on the parts thread 4sale you might check out
    WFLC The REAL #321 Kentucky Drag Boat Association 2016 NJBA 10.0 High Points Champ

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    Senior Member Lildave's Avatar
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    LS1 is an aluminum 5.7 that's about 325hp depending on what it comes out of.

    LS2 is an aluminum 6.0 that's 400hp.

    They are both Gen 3 small blocks. They are actually the same block....and I'm pretty sure the same stroke. I believe the difference is bore (sleeve) size.

    An iron block 6.0 truck engine would still save you 200 plus pounds and be much cheaper than the aluminum version.

    Before this starts a BBC vs LSX riot.....this is if weight is his main concern and he's going to be lets say under 500ish hp.

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    Senior Member TNYoungblood's Avatar
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    Senior Member flatwater's Avatar
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    Quote Originally Posted by TNYoungblood View Post
    I don't see going to a Aluminum set of heads makin that much difference, might be wrong

    There are a set of Brand new Aluminum BowTie heads on the parts thread 4sale you might check out

    I have been keeping my eye open... guess i missed that one, I'll go check er out. thanks

    Quote Originally Posted by Lildave View Post
    LS1 is an aluminum 5.7 that's about 325hp depending on what it comes out of.

    LS2 is an aluminum 6.0 that's 400hp.

    They are both Gen 3 small blocks. They are actually the same block....and I'm pretty sure the same stroke. I believe the difference is bore (sleeve) size.

    An iron block 6.0 truck engine would still save you 200 plus pounds and be much cheaper than the aluminum version.

    Before this starts a BBC vs LSX riot.....this is if weight is his main concern and he's going to be lets say under 500ish hp.
    I'd say I'm only running 450hp now. I'll have a better idea after I dig into the motor a bit more. 500 is lots for what I'm doing. Anymore and I'm affraid my arms would get ripped off before I got out of the water. It's tough playing tug of war with a big block!

    Quote Originally Posted by TNYoungblood View Post
    LOL

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    Senior Member desrtrat256's Avatar
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    Quote Originally Posted by cstraub View Post
    AFR265, Dart 275, Brodix 270 or a set of take ZZ502 heads, Rovals, is what you need to look for.
    Chris, What is your take on the dart 275? I have tried to research them but seems there is very little info or build sheets using them. Curious of their limitations.

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