427 or 454?

[beached1]

Ok, here's my dilemma. I am currently running a fairly stock 454. Cast crank, cast flat top pistons, large oval port heads, TorkerII intake, Demon 750 dp, roller rocker arms, and Jacobs ign, Crower cam. I am in the proccess of having my engine balanced. My buddy who owns a machine shop and is doing this for me, has a set of balanced TRW pop up forged pistons (same bore) and a steel crank all ready to go if I wanted. The catch, it's a 427 crank. He's hooking me up with all this for free so it's no sweat off my back either way. The crank would be a trade. The owner of the forged steel crank wants my 454 cast. Both cranks are in good shape. If I were dropping this in a car, I wouldn't even hesitate. I would go with the 427. But in a boat? So, my question for all you motorhead jetboaters is, should I go with the higher comp, better pistons, and steel crank or is there no replacement for displacement?
I have a 20'6" Omega bow rider. Jacuzzi WJ modified by MPD with a B impeller.
Your opinions are appreciated. Thanks in advance,

[Heatseeker]

There is no replacement for displacement!
Also, I think you'll want the longer stroke of the 454, since torque is what really moves a jet boat.
Just an my opinion.

[1tricky1]

Testing, testing....tap, tap...is thing on? (my first post). I agree, no replacement for displacement. I've always been told jets love and need all the torque they can get!

[FoMoCo]

Wtacha going to do with the boat? tis my belief that shorter stroke especailly a Forged crank will last a lot longer at 6000 rpms than and cast crank 454!! I am running a short stoke 429 BBF turning a MPD prepped B+ impeller at 5400 rpms! 76 mph(no diverter or droop yet). I had a buddie turnin a little above 6000 rpms with 427 BBC, with a really good pump runnin 83 mph( no diveter or droop)!! the 427 was just a stock L72 with a cam change and a tunnel ram!
So I would put some thought into it!!

[Bense468]

You know they call the 427 a mystery motor. Because it produced more HP then they ever claimed it did. Is it an L88? I would go with it.

[spectras only]

Beached1 ,the difference in torque is miniscule between the 427 and 454.Depending on camshaft, your peak torque comes in at between 2800-4700! With the shorter stroke crank ,you can go higher RPM's safer ,so I would go for the steel cranked 427.I've had the 460 in my jetboat ,and after changing it to the 429 ,I didn't notice any difference in the holeshot [20.10 daycruiser].Even with a tight fresh pump you're at 4-5000RPM instantly,where you're at your max torque ,above that you need HP gains for top speed performance,which is no problem with 427's.The 429 in my [ex boat,just sold it] is still running strong[13+years]with the constant high RPM's most other jet boats experiencing.

[Costello]

At lets say 1 hp per cubic inch, what do you lose all things being equal here? 30 horsepower!! All things are NOT equal however; as you should be producing more power with the better pistons. On top of that with the balanced rotating mass, you will have less negative harmonics going on, which will result in better cylinder sealing, and ultimately longer ring life, not to mention much much easier on your bottom end bearings. To top it off, you will have the insurance of a better crankshaft less likely to fail with a) the balancing, b) better metallurgy. Scott Cone in his ATTITUDE Kurtis 501 won the TE 9 second Championship last year with a 427. http://free.***boat.net/ubb/wink.gif

[1tricky1]

I think I have an extra .02 here. Nothing against the 427. It can be an awesome engine in full race dress. But as much as you put into the 427, the 454 will be as good, and with more ci. and more torue. I agree with the others about a steel crank, it's nice to have. But I've seen cast 454 cranks spin close to 6,000 for quite some time with no problems. As long as the motor is built right and the crank is ground properly. You have quite a large boat capable of hauling a nice load of people and gear - torque is essential there. If your searching for tenths on the 1/4 mile with a light load, maybe the 427 would rev quicker. I guess it just depends on how you want to use the boat. I'd like to hear what you go with and how it works out for you. Good luck!

[beached1]

Hey thanks guys for your input. I'm really leaning towards the steel crank. I'm not looking to win any races with this hull at all. Unless someone in a canoe flips me off. http://free.***boat.net/ubb/wink.gif But I love to run around the river at about 4200/4500 all day. A steel crank would really help I think. I really wish it was a 454 stroke, but I'm hoping if I go with this 427 I won't lose any HP. I'm hoping the TRW pop ups will pick up the slack if any there. Hmmmmm.