Upgrades
#1
Thread Starter
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Joined: Aug 2021
Posts: 248
Likes: 99
From: St. Louis, MO
Hey all appreciate any input on some future upgrades - not getting to call out a specific season for these upgrade because I’m focused on the remaining bit of summer.
Had motor and drive rebuilt summer of 22’ so first full season with it. Did some tuning, props, and seat time which made a big improvement. Started at 73 and darn near touched 80 back in June, 79.7. It’s got 80 in it just don’t have a lot of opportunities to run it wide open in good water.
540 with Dart 310’s, CMI’s, Dart intake, and a 1050 Pro Systems. B1 with XR 1.50’s, 28p B1, IMCO lower standard -0. Made 640 tq @4700 620 hp @5700. Currently turn the boat to 5450 with this prop which is about 7-8 hp from peak.
Heads were just redone with valve job, springs valve’s etc. Initial thought was to sell these and get a set of AFR CNC w a cam swap. The raised intake ports make me nervous going from a .300 to .375. I doubt anything is going to line up. Alternatively, spoke w a head guy about working my Darts, doing 2.30 valves, port work, swapping to a Vic Jr intake and a new cam. That would be the easiest from a plug and play perspective. Probably not a huge $ consideration between new heads or working my heads but the raised exhaust hasn’t something I want to deal with. Has anyone swapped similar raised exhaust ports? Is it a pain or can it work?
Last piece is considering a new lower IMCO SC -2. This is on a 27 Fountain and seems others have had good success. My X is 18.5”. Assuming the boat likes a shorter drive, what kind of mph can be picked up?
No real goal in mind but would like to pickup 5/6 mph in a realistic world.
Thanks
Had motor and drive rebuilt summer of 22’ so first full season with it. Did some tuning, props, and seat time which made a big improvement. Started at 73 and darn near touched 80 back in June, 79.7. It’s got 80 in it just don’t have a lot of opportunities to run it wide open in good water.
540 with Dart 310’s, CMI’s, Dart intake, and a 1050 Pro Systems. B1 with XR 1.50’s, 28p B1, IMCO lower standard -0. Made 640 tq @4700 620 hp @5700. Currently turn the boat to 5450 with this prop which is about 7-8 hp from peak.
Heads were just redone with valve job, springs valve’s etc. Initial thought was to sell these and get a set of AFR CNC w a cam swap. The raised intake ports make me nervous going from a .300 to .375. I doubt anything is going to line up. Alternatively, spoke w a head guy about working my Darts, doing 2.30 valves, port work, swapping to a Vic Jr intake and a new cam. That would be the easiest from a plug and play perspective. Probably not a huge $ consideration between new heads or working my heads but the raised exhaust hasn’t something I want to deal with. Has anyone swapped similar raised exhaust ports? Is it a pain or can it work?
Last piece is considering a new lower IMCO SC -2. This is on a 27 Fountain and seems others have had good success. My X is 18.5”. Assuming the boat likes a shorter drive, what kind of mph can be picked up?
No real goal in mind but would like to pickup 5/6 mph in a realistic world.
Thanks
#3
Thread Starter
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Joined: Aug 2021
Posts: 248
Likes: 99
From: St. Louis, MO
#5
The AFR heads are nicer then the dart 310s, not 6 mph nicer though. The fact your Engine made more tq then hp, however teslls me your cam kinda on the small side or quite advanced or both. What are your cam specs, do you have the short CMIs with captains call where reversion is a concern?
#6
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Joined: Aug 2021
Posts: 248
Likes: 99
From: St. Louis, MO
I was given a couple different cam spec's although both sort of close..
114 cl, 109intake / 119 exhaust 622/646 lift
I also received another cam spec from them, so not sure which one is accurate.
241/253 @50 615/630
We're not on great terms, so unless I pulled the cam and somehow measure it i'll probably never know.
114 cl, 109intake / 119 exhaust 622/646 lift
I also received another cam spec from them, so not sure which one is accurate.
241/253 @50 615/630
We're not on great terms, so unless I pulled the cam and somehow measure it i'll probably never know.
Last edited by 540Fever; 08-29-2023 at 06:01 PM.
#7
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Joined: Apr 2010
Posts: 124
Likes: 38
From: Holland
The AFR heads are nicer then the dart 310s, not 6 mph nicer though. The fact your Engine made more tq then hp, however teslls me your cam kinda on the small side or quite advanced or both. What are your cam specs, do you have the short CMIs with captains call where reversion is a concern?
#10
My vote is a cam swap and whipple it....then you don't have to worry about how the heads flow....however I have not had my boat consistently running more than a few weeks over the last few years so I guess I'm the bad advice committee hahahaha
As others have said...I would leave it unless you're doing something drastic like adding a blower. You can honestly probably play with labbing props and get a couple more MPH and be cheaper than more engine mods on a perfectly good running engine
Just my opinions lol
As others have said...I would leave it unless you're doing something drastic like adding a blower. You can honestly probably play with labbing props and get a couple more MPH and be cheaper than more engine mods on a perfectly good running engine
Just my opinions lol





