The 454 is not the torque monster many give it credit for. It like the 460
ford suffer from bad runner design and restrictive intake and exhaust
design. That is why many performance marine engines are based on 427's
stroked to a 482. A far better design of bore vs stroke and much more
efficient heads. Also why many jet boats rand 455 olds and 428 fords.
The 340 in my cuda is bored 30 over, stock stroke, with ported and polished
heads and performer rpm cam and i dynoed it at 433 hp and 450 lb ft @ 3900
rpm. The 383 in my duster is 425 hp and 495 ft lb. And my dads 440 is 455 hp
and 550 lb ft @ 3200. That stroker small block should easily be at those
numbers. High torque and low hp means that the engine develops power down
low. Hp is not measured just a calculation of torque and rpm. I cant
remember it right off the top of my head though.
Sent from my Verizon Wireless Droid
-----Original message-----
From: e b <[email protected]>
To: UnifliteWorld <[email protected]>
Sent: Tue, Apr 10, 2012 18:19:39 GMT+00:00
Subject: RE: [UnifliteWorld] 27" Express Cruiser motor trannie swap
a brand new 454 big block GM MAG crate marine engine is rated at 392 HP at
5000 rpm and has 447 ft lbs of torque at 4000, your figure of 500 ft lbs at
2500 rpm seems off to me even with a stroker crank, id love to see the dyno
figures on the motor, 500 ft lbs is certainly doable for a small block, but
3500 or 4000 rpm seems more realistic.
Date: Tue, 10 Apr 2012 09:53:56 -0700
From: [email protected]
Subject: Re: [UnifliteWorld] 27" Express Cruiser motor trannie swap
To: [email protected]
John,
I don't know what engine my boat had when new. I bought it 12 years ago and
it had a 1978 Chrysler Marine 360 in it at that time. The boat is a 1970,
so it most likely had a 318 or 340 in it when new. The transmission was the
VD with 1.5/1 reduction and appeared to be original. As far as I know, the
27 Express Cruiser was available with a single small block, a single big
block, or twin 318's. I've not heard of twins larger than 318's.
The twin set up I saw in Sitka did not have a reduction gear on the
transmissions so it would have more fore and aft room for the engines. I
think it had 13x11 props on it, or something in that range. I remember
shuddering at the thought of trying to work on the outboard sides of the
engines.
I did not have to change the shaft angle or length when I changed
transmissions. I just moved the engine back about four inches and used a
three inch longer shaft coupler. The VD will take a fair amount of to
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