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legend 117
08-11-2005, 07:00 PM
hey guys got this thing bone stock down to dist points,with a 14.25x21 mich stainless steel prop and one person 0f 200lbs running 4600rpm at 52 mph non gps,any tricks to improve speed other than repower?have been told install new vortex heads,4bl carb and intake and special thunder bolt ign.thanks for your help and one last thing looking for seat back cushion behind drivers seat it is white with black bead!

onesubdrvr
08-11-2005, 07:29 PM
hey guys got this thing bone stock down to dist points,with a 14.25x21 mich stainless steel prop and one person 0f 200lbs running 4600rpm at 52 mph non gps,any tricks to improve speed other than repower?have been told install new vortex heads,4bl carb and intake and special thunder bolt ign.thanks for your help and one last thing looking for seat back cushion behind drivers seat it is white with black bead!
If Memory serves me correctly, that package gave 185hp, a Vortec engine (v-6) with 4bbl puts out 220, pretty healthy increase, good for about 3-4 mph. Also, prop test, prop test, when you think you've got the right one, prop test some more.

So you have to decide if the $ is worth it (you're gonna pay atleast $500.00 for the heads, $200 for the manifold, $350.00 for the carb (someone please check me on my prices))-previous prices are new estimates. So a little over a grand, so is it worth the 4mph? What about exhaust, do you have through hull or hub only?

Wayne

mikev
08-12-2005, 11:20 AM
i put the edelbrock 4bbl intake and carb on mine about 500 got me 400 rpms more and a couple of miles an hour biggest bang for the buck. after that repitched the prop and got it lab finished. for 2 more mph. i wouldnt do much more than that waste of money and from what i understand thru hull exahust on a v6 wont gain you anything. this is what i want to do next 350 v8 (http://www.1800runsnew.com/gmpp.htm)

smokediver
08-13-2005, 01:27 PM
i put the edelbrock 4bbl intake and carb on mine about 500 got me 400 rpms more and a couple of miles an hour biggest bang for the buck. after that repitched the prop and got it lab finished. for 2 more mph. i wouldnt do much more than that waste of money and from what i understand thru hull exahust on a v6 wont gain you anything. this is what i want to do next 350 v8 (http://www.1800runsnew.com/gmpp.htm)
I did the 4.3 to 5.7 conversion ... check out merc.'s remanned engines . they are turn key ....

wiltok
08-15-2005, 07:13 PM
I have the exact same boat getting the same numbers. I've hit 53 on the GPS. What is interesting is that I'm getting those numbers running a 19" pitch prop. My RPM is at the upper end of the range - 4800. I tried a 21" and it reduced my upper RPM's and lowered my top speed. What is your WOT rpm and what brand prop?

legend 117
08-15-2005, 08:39 PM
i have a 14.25x21 mich stainless steel i just bought of iboat.com(only 178.00)i was thinking of trying a 4 blade 14x19 but wasnt sure if it would over rev,trimmed out i am running 4400-4600 rpm.how much rpm can this engine take?also if any one has prop ideas or props i can try let me know!p.s boat came with a 14.5x22 raker and only turned 4000-4200 running about 49-50mph.lastly if some one has 4bl carb and manifold set up please let me know!
I have the exact same boat getting the same numbers. I've hit 53 on the GPS. What is interesting is that I'm getting those numbers running a 19" pitch prop. My RPM is at the upper end of the range - 4800. I tried a 21" and it reduced my upper RPM's and lowered my top speed. What is your WOT rpm and what brand prop?

The Hedgehog
08-15-2005, 09:36 PM
We did a through hull conversion on my father's 1990 4.3 last winter. Nominal speed increase as the 2bbl is the bottleneck. This winter will put on an Edlebrook Performer manifold/cam combo, some head work, demon carb and a few other goodies. We are expecting between 235-250 hp with the nice nimble feel of the v-6. Should be fun. If you want to go radical there will be plenty of room for a procharger.

Let me know if you are considering a through hull conversion. There are a few steering obstacles you need to know about.