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TOPIC: 79 Conquest 280 leg gear ratios

79 Conquest 280 leg gear ratios 26 Aug 2017 15:08 #1

  • Johnny 5
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Would anybody have a reasonably accurate guess as to gear ratios in a 3250 w/5.7's and 280 legs? I'm thinking about picking up a pair of legs if I can get them for a good enough price and redo them ahead of time to minimize out of water time. Also looking for recommendations for a 383 ie: comp ratio, cam, and maybe Qjet replacement, I would like to go aluminum heads and intake to dump some weight from what seems to be a stern heavy boat. Oh Yeah and the f/g bimini is coming off.
Thanks in advance

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John, Laurie and official boat dogs Rosie and Peanut(Jose)
'79 Bayliner Conquest
twin 350's volvo 280's
Boston Bar BC/ Boat in Vancouver BC

79 Conquest 280 leg gear ratios 26 Aug 2017 16:23 #2

  • 2850Bounty
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Johnny 5 wrote: Would anybody have a reasonably accurate guess as to gear ratios in a 3250 w/5.7's and 280 legs?
The 280 is a 3 pc drive. Upper unit "Transmission", "Intermediate housing" and "lower gear unit".
Are you asking about the lower gear units?
If so, the over-all reduction for the GM 5.7L V-8 will need to be 1.61:1.
All of the transmissions are of the same gear reduction...... the lower gear unit is where the ratio change occurs.


I'm thinking about picking up a pair of legs if I can get them for a good enough price and redo them ahead of time to minimize out of water time.
NOTE: when mixing/matching AQ series drive components, you must follow the critical OEM shimming procedure.


Also looking for recommendations for a 383
Please read my posts in this thread.
www.baylinerownersclub.org/index.php/for...cs/80958-383-stroker

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Rick E. Portland, Oregon
2850 Bounty Sedan Flybridge model
Twin 270 HP 5.7's w/ Closed Cooling
Volvo Penta DuoProp Drives
Kohler 4 CZ Gen Set

79 Conquest 280 leg gear ratios 27 Aug 2017 05:20 #3

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Thanks Bounty, I was thinking complete legs not just lowers. I read the 383 thread I still need to get some $ figures for parts vs complete engines. I will get in touch with Blueprint engines about a cam substitution on on of the aluminum headed 383. Will also check with the shop that does my race motor machining fo complete engines as well as total costs for me to build them but as an individual my parts cost is going to be substantially higher than a volume purchaser. A pair of 406's might be feasible also but they have some issues that require mods to be done.

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John, Laurie and official boat dogs Rosie and Peanut(Jose)
'79 Bayliner Conquest
twin 350's volvo 280's
Boston Bar BC/ Boat in Vancouver BC

79 Conquest 280 leg gear ratios 27 Aug 2017 11:28 #4

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Johnny 5 wrote: Thanks Bounty, I was thinking complete legs not just lowers.
Ah...... I see!



A pair of 406's might be feasible also but they have some issues that require mods to be done.
If the 406 is a larger bore 400 cu in SBC, I would caution you regarding the Siamese cylinders posing an issue.

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Rick E. Portland, Oregon
2850 Bounty Sedan Flybridge model
Twin 270 HP 5.7's w/ Closed Cooling
Volvo Penta DuoProp Drives
Kohler 4 CZ Gen Set
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