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-   -   468cid vs 454cid.. How much HP difference? (https://www.offshoreonly.com/forums/general-q/39438-468cid-vs-454cid-how-much-hp-difference.html)

Waterfoul 12-23-2002 08:07 PM

Yet ANOTHER use for duct tape!! Gotta love Duct tape. Hmmmm..... sounds like a topic for a new thread!! Check the General Discussion soon......LOL!!!

Mike

KAAMA 12-24-2002 10:02 AM

Just for assurance...
 
bt, Just for a precausion, I think it would be WISE to PM Tinkerboater and ask him how he does it step-by-step BEFORE you begin to do any of these bore notching mods! Tink has done several of these and is a wizz at it! I think excersize a little wisdom to at least talk to someone who has done it a few times BEFORE you get started. That way he can help you to avoid any unforeseen pitfalls and make these mods a sucess!

blue thunder 12-24-2002 10:21 AM

Oh no... don't worry Kaama. I have it all figured out. Just got done with the second engine. Had a hellova time getting all the way to the bottom of the cylinder with the die grinder, but its done now. Had to go in from the crank side. Whew, what a job that bore notching is!! Boy I hope this works!! :D :D

BT :cool:

(PS, I haven't decided if I'm gonna do it yet. Still pondering. ;) )

blue thunder 12-24-2002 10:56 AM

Seriously though Kaama, I was just looking closely at this area on my blocks and they already have notches. More of a step I would say then what JimV showed. Is bore notching simply smoothing this step into more of a chamfer?

Thanks for the advice,

BT :cool:

Allan4 12-24-2002 11:37 AM

KAAMA, thanks for the reply. Looks like I will bypass this effort. Later:D

KAAMA 12-24-2002 01:03 PM


Originally posted by blue thunder
Seriously though Kaama, I was just looking closely at this area on my blocks and they already have notches. More of a step I would say then what JimV showed. Is bore notching simply smoothing this step into more of a chamfer?
Yes, the factory may have done it on your block(s), but it as you say more of a; "stepped" or more of a machined look to it and appears to be crude at best. Doing the bore notching with a die grinder you can make it wider and deeper and do a much better job by radiusing it out much better and making it a smoother transision of air flow.

Allan4, I understand. They're your engines---you can certainly do as you wish with them. You guys with 454's are always looking for a little extra power and this is a very good, inexpensive and reliable way of doing it without adding any complications to the mechanics of an engine. Anytime you can increase the correct kind of air flow within an engine without adding parts is like getting FREE HP. Of course it's your decision, I was just hoping to see you guys benefit from something like this and get the most out of your 454's. :)

Waterfoul 12-25-2002 08:00 AM


Originally posted by blue thunder
Seriously though Kaama, I was just looking closely at this area on my blocks and they already have notches. More of a step I would say then what JimV showed. Is bore notching simply smoothing this step into more of a chamfer?

Thanks for the advice,

BT :cool:

Yes, making it into a nice, smooth, radiused chamfer. That's the goal here. Trust me, it's easy!!! Just remember to use the HEAD GASKET you're going to use as a template.

Mike

birdog 12-25-2002 08:59 AM

Do you think it's even worth doing on 468s ?
Free HP sure is nice !!!!!!1

blue thunder 12-25-2002 09:38 AM

Since my engines already have the fly cut notch, and because of the .060 over, do you guys still think it is worth 30hp? Trying to weigh the risk to potential benefit.

BT :cool:

KAAMA 12-25-2002 05:40 PM

birdog and blue thunder, not trying to be short here, but at this point it would probably benefit you guys if you went back and RE-READ all of my posts within this thread.

Blue Thunder, The "fly-cut bore notch" that comes from the factory is CRUDE at best and I have already addressed it in a previous post within this thread.

Birdog, yes you will definately benefit from a bore notch with a 468 and I have pretty much already addressed it in a previous post within this thread.

Not convinced yet? Call "JimV" at (616)735-0800 9m-5pm. EST. Or PM Tinerboater and discuss it with him. It's a true and cheap horsepower maker! :)


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