The motors started life as 500 efi's.The motors are now 555 cubic inchs, have afr 357 cnc heads with Vortech Superchargers, and make a little more power than the 850 (that I call them)however when someone looks in hatch and sees the stock 500 efi intake they do not believe the power they make. They actually made a little more than 1000 in both horsepower and torque. However I am unable to turn them to 5800 rpm in the boat regardless of the prop used which is were it made over 1000. I really believe the 500 efi intake are not able to flow enough volume to support the rpms I would like. I can put on a pair of 31's and spin 5700 or I can spin 34's 5600. My engine builder warned me about this and it will likely get changed before next year

My x dimnesion is 18" and I am running SCX uppers with -2 sc lowers with 1.3? gears ( the scx uppers are geared a little different so I do not now the exact number). Prop is Mercury labbed 34 maximus with 15 1/4" diamater.

The only problem I have had with drives is during the middle of this summer one drive developed a shifting problem. We tore the upper apart and the gears looked brand new (encouraging). The shifting problem turned out to be Imco puts a rubber plug in the hole above the shift shaft. The plug is to long and after a little wear on the cone clutch it would no longer shift. I cut the plug in half and it has been problem free since. The drives are 2 seasons old and have about 180 hours and close to 7000 miles on them. The first season of these drives they had 850 horsepower and 800 foot pounds of torque (about 100 hours and 4000 miles). i guess with all this talk about breaking these lowers we will tear them down over the winter and have a look.

I should also mention that i really believe in Torco #6 drive fluid in these drives. I believe when you use like mercury High performance gear oil that it is so thick that it get slung away from the gears and flows slowly and can not get back into contact with gears (kind of forms an airpocket around the gears) where as the torco flows very similar to water even cold. I have no proof of this but have had great results after changing.

The boat has been 117.9 MPH and this was during August. When the water and air temp cools down I really expect this number to grow.

If you have any more questions I will try my best to answere them.
Allen

good running boat... you should sell it to me for 50k!

29 Scarab..thanks for the comeback..i have also experienced the same problem with my motors..i had them done by MRD in L Island and dynoed by Richy Zul and they have solid lifter cam shafts ..they pulled them to 7000 rpm and made 900 hp, but once put in the boat with cmi elbow tops...tried different props and could only get 6000 rpm without rev limiters installed..i also tried a set of 32 maximus and didn't like them at all..lost about 3 mph. Hering is the only prop i will run right now. i am in the process of ordering 3 7-blade herings for my application. should have my boat complete for the key west poker run...

Id love to man!!!! Get that 26 dialed in and lets do it!!

Its not conducive to chatting...too much for you.

I don't care about that now. I will have intercoms for everyone so we can all wear headsets, and idle, and be able to chat. I will radio you from my CB and ask if you still have the hatch off and the pogo sticks extended.

U will name it Death Bed....and your CB handle will be The Grim Reaper.

(MS170)


back on topic:

what is the latest with the boat?

Tyler picked up new piston last night. He has the Stbd motor torn down to bare block and has the #4 hole honed. He will put back together MON/TUE...and ship back to RF...fingers crosssed. I talked with Lil R...he spoke to Dave @ CMI and headers will be shipped back to RF on Tues. As of now it looks like we are still on pace for another trip to Reggies Casa this coming weekend. OH...and truck should be ready on Monday. Please dont blow it up this time. p:

So what really went wrong with the engine and the header for that matter ?