Extension box on a 29
#1
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Extension box on a 29
I'm sure this topic has come up before, but I have a fairly detailed question.
I have a 1995 29 that came with a stock HP500 carb.
back in 2006, I built the motor with a ProCharger and with a few burnt pistons later finally tuned it to what ran 713 Hp on the dyno and 78 MPH on GPS with a XR upper, std lower and 28" Bravo. Actually got 79.6 twice, but never quite to 80
I took the Proharger off a couple of years back as I was trying to sell the boat, but not having much interest in it, so I redid the interior last year and decided to keep it
I pulled the motor last fall to have a look at the components and freshen her up. Everything seems pretty good, except that the original roller cam has some wear on the flank of#7 exh. So I am replacing it with a bit lumpier unit to see if it'll squeak 750 hp on the dyno.
Never had external steering on it, but I think its time. But have been wondering about either a shorty drive or an extension box with raised X dimenson.
Shorties seem a bit pricey, but according o CP Performance, I can get a Mayfair ext box with add-on dual ram steering for about $4300
Does anyone have any experience with speed numbers and handling before and after with an extension box?
Thanks
I have a 1995 29 that came with a stock HP500 carb.
back in 2006, I built the motor with a ProCharger and with a few burnt pistons later finally tuned it to what ran 713 Hp on the dyno and 78 MPH on GPS with a XR upper, std lower and 28" Bravo. Actually got 79.6 twice, but never quite to 80
I took the Proharger off a couple of years back as I was trying to sell the boat, but not having much interest in it, so I redid the interior last year and decided to keep it
I pulled the motor last fall to have a look at the components and freshen her up. Everything seems pretty good, except that the original roller cam has some wear on the flank of#7 exh. So I am replacing it with a bit lumpier unit to see if it'll squeak 750 hp on the dyno.
Never had external steering on it, but I think its time. But have been wondering about either a shorty drive or an extension box with raised X dimenson.
Shorties seem a bit pricey, but according o CP Performance, I can get a Mayfair ext box with add-on dual ram steering for about $4300
Does anyone have any experience with speed numbers and handling before and after with an extension box?
Thanks
#3
scarab
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A good friend of mine had a 1999 29 scarab with a single 502 with a whipple and he tried the stern jack and he only got 1 mph out of it but he did not do the shorty lower unit. Hope this helps
#4
I put a -1 imco on my scarab 22 and it made a big differnce in handling and gained a little in top end, do not have to trim up real high and runs better in the chop. I am running close to 600 hp and i run a 30 labbed bravo 1. I did have to go to a 4 blade when i went with the imco . I do have drew marine sidewinders on the drive to help the chime walking. I have done 82.5 on gps .
#5
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Thanks for the feedback guys.
I'm thinking that it would be alot of money and testing of high dollar props to make it right . All that and may only see a couple of MPH!
Will have to ponder the idea some more........
I'm thinking that it would be alot of money and testing of high dollar props to make it right . All that and may only see a couple of MPH!
Will have to ponder the idea some more........
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I would call and talk to someone like IMCO. Tell them what your idea is and what you have. Measure your x-dimension before you call though, cause they will ask. I talked to them when I was looking at putting a shorty on my old boat. They were very helpful.