doggiedave

Good afternoon, I have 1987 23 scorpion limited, original engine was a 260hp/350. I had a 406 smallblock n/a that i'm replacing with another 406 that will be equiped with world products ported heads comp hyd-roller, stainless marine semi-dry exhuast, and a 177 weiand blower at 6psi. any idea about what kind of top speed I can expect? my last prop was a mach 14.5/ 23 4-blade how much more pitch will the new motor pull last go I gps at 70 on the right water. the drive is a cobra 1.50, the x-dimension I believe is a little deep, not sure any suggestions on this set-up, thanks

scorpion king

Sounds really cool! My Dad has a 83 230 with a N/A aluminum headed 406 running that same 23 marage + and has a lot of prop slip I think around 18% ,runs like a basterd cat though I just with we could geter dailed in ,I had the same hull with a 427 and have similar problems with slip ratio at 20% ,I have been thinking of trying t revolution 4 blade just to get a better hook. I love to see some pictures of that animal

Scorpion Paul

I have a 210 Scorpion That was a 260/350 That I just replaced with a 355 balanced forged bottom end 10/to1 comp. Dart 67cc iron eagles w/vortec chambers Comp Cams XE262 cam and valvetrain. I also installed a Schieffer 11 pound flywheel and The throttle response is great.Weind intake thru hull exhaust, was messing with a weber 750 that I just couldnt get right .She only has 5 hrs on it so im not pushing it yet but I have run 53mph on gps at 4400 with a 23p lazer II. I scrapped the weber and put a Holley 600 and had to winterize it before i had a chance to check it out. I do agree the x dimension is a limiting factor on the speed. What are you guys running for timing. I have been cautious because of the compression kept it at 33 for now.

doggiedave

Thanks for the responce. will keep you posted. I'm still collecting parts to finish the build, have to do it on a budget. next stop is a 850 sea demon blower calibrated carb. then off to the machine shop. I've taken an interest in your build let me know how your prop change works. I could blow out my prop on hard aceleration when coming on a plane with the last engine. so I anticapate a prop change will be needed with the additional hp I hope to build with the blower motor

scorpion king

I run around 32 Degrees of timing also ,but I have 9.2:1 and 87 octane fuel .I had a bad experiance with my Dads 230 Scorpion a couple years ago ,We built a Edelbrock headed 406 with flat tops and I really did not think about it having 64cc chambers and flat tops as being high compression at the time ,We just timed it as we ran it setting it ahead untill it pinged and then backed it off untill it stopped. Burnt a piston so we changed to a forged set and I set the timing this time with a light at 32 ran it and it pinged so we set it by ear again and it seemd to run great ,the next day I checked it with my light and it was only 22 degrees thats when I figured it out that low octane and 32 degrees of timing did not go well together so we changed the set up and put a dished piston in it that yeilds 9.7 and it runs great on pump gas at 32.As Far as carbs the best I have run to date is a Predator ,I thought I had a problem with mine so I switched it for the 900 BG (shown in the picture) turned out it was not the carb it was a tight Exhaust valve.Acted just like a vacume leak and a Predator will not work with any vacume leak. .