Well finally made the trip to the dyno with one of the Panthers new power. (the red one, the blue one is JimV's 565) The twin is almost finished.



This engine started as a Merc 425, I kept the original internal forged crank and rods, added SRP pistons 9.6:1, new cam, Merlin fully wedge ported JimV heads, Holley Barry Grant 750 carb and Wieand Stealth dual plane welded and ported intake.
560 TQ @ 5250rpm and 590 HP @ 6250rpm



I will be rigging this week and hopefully also finshing the other later this week. I can't wait to get on the water!!!

Pretty! What speeds are you expecting with the new power?

I don't know what the real speed will come out to. Before I was running 71 with around 850HP (Merc 425's). now I will be running 1180HP.

850 HP / 71 MPH = 11.97 HP/MPH
So if you divide 1180 HP / 11.97 HP/mph = 98.57 MPH.

I know that the hull is not linear in speed gains and the TRS drives don't like it over 90, so with all that against me if I see 83-85 MPH I will be happy.

Niiice ! I saw you're in Grand Rapids, stay dry and don't use that boat on the streets.... Hope you are well and not too hard hit by the flood!

Thanks,
And I'm dry but they were not fairing so well north of me. I think they declared a state of emergency north of me.

Like what I see so far- keep us posted with more pics!

Some of my progress pics are in the SCARAB PICs thread

Bottom of this page

http://www.offshoreonly.com/forums/s...t=10712&page=6

and

http://www.offshoreonly.com/forums/s...t=10712&page=7

Speaking of the SCARAB PICS, are there only 5 to 6 scarabs on here? Of course mine is the "classic".

Let us know how fast you do go with all that juice. I'm just hoping for 60 next month. Were the engines dyno'd with the 750 carbs?

Yes they were dyno'd with 750's. I believe I would have been over 600 with 850's. I also chose to use the Wieand Stealth dual plane intakes rather than a single plane Dart. I was told that going the 850 single plane way I would lose low end torque and push out the usable HP to 6500, but I would be well over 600HP. If you look at the dyno sheet between 4000 and 5750 it flatlined the TQ, Also the torque never drops off.

JimV put this combination together for me. He welded up my intake runners and ported them to match the wedge inserted intake runners on the heads. (this is not port matching, this is a full all out head port job) this changed the runner volume from 320cc to 315cc which increases torque. He knows his s#it.

What I thought was strange was with the Merc 425's my jetting was 77 6.5PV in front 87 no PV in the back. I actually had to jet down to 76 6.5PV front 82 no PV back with this combination.

The other engine will be done first of next week, I plan on being on the water next weekend to start trying props.

I dont see the need for a dart single plane unless the displacement is big enough to get the velocity up. I have seen alot of interesting info on the edelbrock rpm air gap-I think I have an article on a comparison between the vic jr. and the air gap. Looks like your stuff is already matched up, but I was curious as to why the 750's on what seem to be tricked BBC's. I cant rember my jettting crap right now but the jets would indicate if you could go bigger without losing your low end. It has been awhile since I did engine work but I cant wait to get back in it. I wish I was closer to see the monster in person.