Looking for a Mercury HP 420 Engine Setup
09-29-2015 | 03:54 PM
#1
Thread Starter
Registered
Joined: Nov 2014
Posts: 41
Likes: 0
From: Germany
Looking for a Mercury HP 420 Engine Setup
I have a 454 short block from a HP420 engine. The block will be honed to 00:30. Currently, I am still looking for matching innards. Which heads which camshaft, etc. At the end it should go mainly to top speed and the engine should still run at +/- 700 tours idle.
I'm looking for a cheap but durable setup at maximum power. :-) The whole set comes with a Bravo One drive in a 22 foot boat with 3600 lbs.
Sorry for the bad translation into English.
Mike
I'm looking for a cheap but durable setup at maximum power. :-) The whole set comes with a Bravo One drive in a 22 foot boat with 3600 lbs.
Sorry for the bad translation into English.
Mike
09-29-2015 | 07:13 PM
#3
Registered
Joined: Nov 2004
Posts: 14,068
Likes: 3,668
From: On A Dirt Floor
Duplicate the 420 pretty much exactly and just swap the flat tappet cam for a hydraulic roller with near specs.
That should get you a 700hr reliable package with a bunch of nuts for a 22ft boat.
That should get you a 700hr reliable package with a bunch of nuts for a 22ft boat.
09-29-2015 | 11:56 PM
#4
Charter Member # 55
Joined: Oct 2000
Posts: 20,232
Likes: 2,482
From: Omaha/LOTO
This is the stock cam http://www.cranecams.com/product/car...detail&p=24005
There are much better choices if you go to a roller cam.
There are much better choices if you go to a roller cam.
09-30-2015 | 06:43 AM
#6
Registered
Joined: Apr 2006
Posts: 10,042
Likes: 712
From: Toledo Oh
Parts list?? Its a decent bottom end, forged crank, dimple rods. REplace the top end, with decent alum heads, roller cam and intake... whaalaa, you just picked up an extra 100+ reliable well mannered horsepower.
09-30-2015 | 09:21 PM
#7
Charter Member # 55
Joined: Oct 2000
Posts: 20,232
Likes: 2,482
From: Omaha/LOTO
The 420 is a 454 with GM Rectangular port(118cc) heads,
GM forged crank and rods, TRW forged Pistons with 8.75 Comp Ratio
Crane cam that I listed,
Holley 800cfm carb and Gil Exhaust.
I think a Dart Intake Manifold was used but not 100% sure.
GM forged crank and rods, TRW forged Pistons with 8.75 Comp Ratio
Crane cam that I listed,
Holley 800cfm carb and Gil Exhaust.
I think a Dart Intake Manifold was used but not 100% sure.
10-01-2015 | 02:38 AM
#9
Thread Starter
Registered
Joined: Nov 2014
Posts: 41
Likes: 0
From: Germany
Found a setup online:
Cam Style Hydraulic flat tappet
Basic Operating RPM Range 2,800-5,800
Intake Duration at 050 inch Lift 228
Exhaust Duration at 050 inch Lift 236
Duration at 050 inch Lift 228 int./236 exh.
Advertised Intake Duration 298
Advertised Exhaust Duration 306
Advertised Duration 298 int./306 exh.
Intake Valve Lift with Factory Rocker Arm Ratio 0.530 in.
Exhaust Valve Lift with Factory Rocker Arm Ratio 0.551 in.
Valve Lift with Factory Rocker Arm Ratio 0.530 int./0.551 exh. lift
Lobe Separation (degrees) 114
Intake Valve Lash 0.000 in.
Exhaust Valve Lash 0.000 in.
Computer-Controlled Compatible No
Grind Number H-228/312-2S-14 T1.2
Cam Style Hydraulic flat tappet
Basic Operating RPM Range 2,800-5,800
Intake Duration at 050 inch Lift 228
Exhaust Duration at 050 inch Lift 236
Duration at 050 inch Lift 228 int./236 exh.
Advertised Intake Duration 298
Advertised Exhaust Duration 306
Advertised Duration 298 int./306 exh.
Intake Valve Lift with Factory Rocker Arm Ratio 0.530 in.
Exhaust Valve Lift with Factory Rocker Arm Ratio 0.551 in.
Valve Lift with Factory Rocker Arm Ratio 0.530 int./0.551 exh. lift
Lobe Separation (degrees) 114
Intake Valve Lash 0.000 in.
Exhaust Valve Lash 0.000 in.
Computer-Controlled Compatible No
Grind Number H-228/312-2S-14 T1.2
