full disclosure, these are my assumptions please correct me if you feel im in error or missing something obvious, thanks...
the boat has a merc 260 with a alpha 1 stern-drive. according to this web site the boat weighs 3000 pohttp://boatspecs.iboats.com/Thunderbird_--_Formula__F-20_SC__1981/bp/66b95338). it is my understanding that the previous and only owner never had the engine rebuilt, so it may be getting a little tired. but he did put in a msd 6460 ignition but the tach wasnt hooked up so i cant tell what kind of rpms the engine is able to muster, i will fix that tomorrow(looked it up on msd web site amazing with a search engine can do, lol). i believe a circa 1981 merc 260 should hit about 4200 rpms (asssuming its not overproped) i will know tomorrow if my engine will turn my aluminum 19 pitch prop to those rpms.
now because of my past inexperience with winterizing boat engines i happen to have a completely rebuilt merc 260 with a cracked block. so this is what i have laying around the house, a rebuilt set of heads, an intake and a holley 750 dbl pumper w a 1 inch spacer, model number 10569 that supposedly rejetted for the merc 260, but it was/is an auto carb and not a marine carb.
since these parts are free and easy to bolt-on, lets say i port and polish the heads and intake, put on 750 and the spacer(there is a 650 qjet, right now). and if spend some bucks on a freer flowing exhaust, i would think that these upgrades would be significant, particulary if the engine isnt up to snuff, right now.
so what is the realistic expectations for actual on the water performance difference(it is my understanding that a 20 percent hp upgrade on a boat this big isnt really gonna make a big difference)? any advice would be great, thanks...
the boat has a merc 260 with a alpha 1 stern-drive. according to this web site the boat weighs 3000 pohttp://boatspecs.iboats.com/Thunderbird_--_Formula__F-20_SC__1981/bp/66b95338). it is my understanding that the previous and only owner never had the engine rebuilt, so it may be getting a little tired. but he did put in a msd 6460 ignition but the tach wasnt hooked up so i cant tell what kind of rpms the engine is able to muster, i will fix that tomorrow(looked it up on msd web site amazing with a search engine can do, lol). i believe a circa 1981 merc 260 should hit about 4200 rpms (asssuming its not overproped) i will know tomorrow if my engine will turn my aluminum 19 pitch prop to those rpms.
now because of my past inexperience with winterizing boat engines i happen to have a completely rebuilt merc 260 with a cracked block. so this is what i have laying around the house, a rebuilt set of heads, an intake and a holley 750 dbl pumper w a 1 inch spacer, model number 10569 that supposedly rejetted for the merc 260, but it was/is an auto carb and not a marine carb.
since these parts are free and easy to bolt-on, lets say i port and polish the heads and intake, put on 750 and the spacer(there is a 650 qjet, right now). and if spend some bucks on a freer flowing exhaust, i would think that these upgrades would be significant, particulary if the engine isnt up to snuff, right now.
so what is the realistic expectations for actual on the water performance difference(it is my understanding that a 20 percent hp upgrade on a boat this big isnt really gonna make a big difference)? any advice would be great, thanks...