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Im about to pick up a 454 from a 80's chevy dually. Whats the potential for this motor? Id like to get 300hp? Could i use 781 heads on the truck motor? Should I not buy this and wait for a PASS HI PERF motor?
BTW its going in a 17' Avenger
 

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Im about to pick up a 454 from a 80's chevy dually. Whats the potential for this motor? Id like to get 300hp? Could i use 781 heads on the truck motor? Should I not buy this and wait for a PASS HI PERF motor?
BTW its going in a 17' Avenger
Most likely it will have the exact same casting # on it and say hp passenger, if i remember right, all low deck mark IV block will have the hp passenger casting truck or car. It probably is a 14015445 block, There is a chance it will be a 4 bolt block.
 

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I was gonna say 781's are decent ovals....but after re reading your question...sounds like a block question...my bad. My old machinest told me you could tell a 4 bolt main block by looking at the size of a bolt/plug by the oil filter. Not sure if there is any truth in that. I have a feeling I am about to find out though.
 

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300 shouldn't be any problem getting out of a BBC :cool:

2 bolt or a 4 bolt you'll be fine!!!!!
 

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I was gonna say 781's are decent ovals....but after re reading your question...sounds like a block question...my bad. My old machinest told me you could tell a 4 bolt main block by looking at the size of a bolt/plug by the oil filter. Not sure if there is any truth in that. I have a feeling I am about to find out though.
No you are right mofo! The oil bypass plugs above the oil filter housing will normally give you a clue on the 2-bolt or 4-bolt main. And to add, the 781 oval casting head are good for well over a 300 H/P range depending on the rest of the build! Now we can both get slammed:)devil Mark
 

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Also as an add on if the engine comes out of a c-30 dually chances are it will be a 4-bolt depending on if it is a GMC or a chevrolet dually. believe it or not the GMC normally went to the extreme on engine and trans combos. Could be wrong and it wont be the last time but thats what I have always found! 2-bolt would be a 3/8 plug over the filter and a 1/2 plug on the 4 bolt. Outside of the peanut plug newer heads I have yet to see a block or heads for that matter that didnt say hi/perf passenger in the castings. M
 

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Im about to pick up a 454 from a 80's chevy dually. Whats the potential for this motor? Id like to get 300hp? Could i use 781 heads on the truck motor? Should I not buy this and wait for a PASS HI PERF motor?
BTW its going in a 17' Avenger
Depending on what you do to it, you should be able to make 300 HP standing on your head with a mild cam and 750 carb. As has been stated, out of a dually is more than likely a 4 bolt block. I guess the question is what it costs. It will probably have a cast crank, and depending on your budget and plans you may want to put a set of forged pistons in it which will be more likely to survive in a boat engine, as well as bumping the compression a bit. Are you planning on freshening it up, or just dropping it in with different heads?

The size of the pipe threads in the block above the oil filter are not a sure thing. I have a couple of 445 blocks here, (including a new one that has never been assembled), both 4 bolt blocks, both with 3/8" pipe threads above the filter boss. I had always heard that the early blocks were a 4 bolt if they had two large bosses above the filter.
 

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Discussion Starter #9
I'm looking to put a carb intake and a cam in it for this summer. Then over next winter do some head work and possibly freshen up the bottom end.*
I want to get the right block the first time around
 

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I was thinking that the BBC truck motors already made 300+ HP from the factory! The one in a friends TX turns a A impellor 4400 and the chart shows around 320 HP!
 

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IF you pull the casting numbers, you should be able to get an idea of the block details. For the power you are talking do not think it really makes a difference between 2 and 4 bolt mains. You will find a fair amount of discussion on that point. When you start upgrading the engine, do not forget to pay attention to the bottom end. It is easy to forget about it when you get into the "just a few more Hp" mode.
 

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Im about to pick up a 454 from a 80's chevy dually. Whats the potential for this motor? Id like to get 300hp? Could i use 781 heads on the truck motor? Should I not buy this and wait for a PASS HI PERF motor?
BTW its going in a 17' Avenger
Do yourself a favor, and flip it over and pull the pan and check to see if it is a 4bolt... thats easy. Your gonna have to replace the pan anyway no matter. Buy a 4 bolt ! - so that you can do whatever you want to it in the future.

The potential? Whatever your wallet can handle - Im sure obnoxious can out together an easy 600hp engine for ya out of that old truck block....
 

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Discussion Starter #13
Ok its decided im running a stock 1980's 454 this summer. I figured id need a new carb and intake. Im guessing a 750 carb and does it matter which intake i use? Do intakes make that much of a difference on a stock motor?
 

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It's simple to convert it to a 4 bolt if it's not.
By the caps and machine the extra holes.
Get it line bored/honed and off you go.
Don't confuse this with a real "truck" block with the taller deck.
They never came in light trucks.
 

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Ok its decided im running a stock 1980's 454 this summer. I figured id need a new carb and intake. Im guessing a 750 carb and does it matter which intake i use? Do intakes make that much of a difference on a stock motor?
I would look through the spam section for a good used intake and maybe even a carb! The late model BBCs had oval port heads that leave alot on the table and you may want to change to a different set of heads when you decide to build! And they may be rectangle ports and an oval port intake will not work on rec. ports! 750 carb will work well on the stock setup but an 850 will also so plan for the future! Just my .02!
 

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Discussion Starter #16
I would look through the spam section for a good used intake and maybe even a carb! The late model BBCs had oval port heads that leave alot on the table and you may want to change to a different set of heads when you decide to build! And they may be rectangle ports and an oval port intake will not work on rec. ports! 750 carb will work well on the stock setup but an 850 will also so plan for the future! Just my .02!
so will a rec port intake work on oval (peanut port) heads if i run an oval port intake gasket?
 

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got to use the rectangle gasket :))THumbsUp
 

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It's simple to convert it to a 4 bolt if it's not.
By the caps and machine the extra holes.
Get it line bored/honed and off you go.
Don't confuse this with a real "truck" block with the taller deck.
They never came in light trucks.
Most of the time you only saw the tall deck in a c-60 or bigger! Alot of 427 engines like that! To adapt a 2 bolt to a splayed 4-bolt is really not so uncommon but really depends on induction and intended usage! If you plan to run over 6k for extended periods then yes its worth it. M
 
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