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  1. GN7 On the Dyno
    What A/F ratios are you guys seeing that work well for a Naturally Aspirated BBC? My engine seems to want a richer mixture on the ramp up to WOT, (about 3/4 throttle) then it actually does at WOT itself. Is that normal?
  2. GN7 On the Dyno
    I hooked up an AEM wideband setup in order to monitor/tune my engine. 476 BBC, 9-1, aluminum oval port heads, dual plane intake, 850 quick fuel marine, Berkeley jg A- impeller fresh from MPD, 5400rpm wide open. at around 3400-3600 I'm bouncing between 12.1-12.6 on the meter, wide open it was...
  3. Jet Boats
    So picked up this boat a couple weeks ago. 1983 17' Targa, full stringers, berk E pump, has a fin, kinda of a cool little boat. I have owned outdrives and outboards before, this is my first jet. Took it out to Inglebright the other evening for a little cruise and the steering feels really...
  4. Jet Boats
    Hey all, about to rebuild my 350 engine that's running a 671 Weiand blower and wanting to know what compression ratio to build it to. It is in a family jet boat that does a race or two a year so it needs to run on 96 or 98 pump gas, has 76cc cast heads, comp blower cam #12404-4 but I would like...
  5. V-Drives
    Curious what compression ratio (and cam specs) you guys are getting away with on pump gas? I am in the process of building a 468 chevy for my Hondo and trying to decide what kind of compression I want to end up with. I want to be on the edge of pump gas, don't mind blending, but do not want to...
  6. GN7 On the Dyno
    What is a safe CR for a pump gas 496. I have been told from 10.5:1. Then another said it would rattle at the CR. What is safe for 91 pump gas? About to order pistons and want to stay safe. This is for a lake boat with a little NOS. Thanks for your help.
  7. GN7 On the Dyno
    At cruise 4,000rpm 2.5-3# of boost, 145* intake temp below blower, Im high 12`s ( 12.8-13.0) Add more fuel to be safe?
  8. V-Drives
    I have a 20ft eliminator mini day cruiser with a turbo 400 and a 461 bbc. built for lake putting and ski time. I have a 12/14 3 blade prop. my racing days are over so the best gear for the all-around would be appreciated. Thoughts?????Thanks in advance! Mark
  9. Parts for Sale
    I decided to not use these on my boat need them gone make resonable offer. Call 765-210-1124
  10. GN7 On the Dyno
    I was wondering what octane I would get away with running if I went with another set of L88 427 pistons just ones designed for the open chamber heads this time around. Could I buy C12 and just mix it a little with 91 pump gas. If so what ratio. These are the pistons I'm thinking of going...
  11. GN7 On the Dyno
    Ok, trying to figure out compression ratio on a proposed build, maybe need an education on the subject. Have a couple assumptions I need help with. Inch to cm conversion is inch x 2.54? Volume of a cylinder is: stroke x 3.14159 x 1/2 bore squared, right? Of course must add in head gasket cc...
  12. Parts for Sale
    Not for sale No longer available for sale Please delete. Thank you
  13. GN7 On the Dyno
    I have #150 on the compression gauge and trying to pick out a new cam. The cam makers always want compression ratio. Is there a way to determine this? Thanks Scott
  14. GN7 On the Dyno
    This is a really general question, I'm just looking to keep my motor "safe" or ideal. And help me get my motor jetted right. It's not a balls out race motor. I have a 496 with a GM 671 blowing about 5psi and two holly 750cfm 4150s. Just say 6500max rpm. I just run premium yes I know it...
  15. V-Drives
    What is optimum air fuel ratio cruise and wide open throttle on a pump gas normally asperated EFI big cubic inch motor? 540 inch , 598 etc. thanks in advance for the info.
  16. GN7 On the Dyno
    Well not exactly variable. it has more compression the longer it runs. No carbon emissions. it stays in the engine. :)
  17. Parts for Sale
    Alright folks, up for sale is a very clean Mercruiser Bravo I outdrive, complete and in good condition. I will be getting some pictures of it tomorrow sometime. I needed one and ended up with two.... Story of my life...:duh: It is mid to late 80's and is a solid 9 out of 10. 1.50:1 ratio, no...
  18. V-Drives
    Hi all, my first post. I have recently purchased an 18'6" Everingham shallow vee boat Looking for suggestions on step up ratio and prop. Motor will be injected LS3, 620hp @ 6,300 & 576 ft lbs @ 5,100 thanks in advance Roger
  19. Outdrives
    Can someone explain any tradeoffs in gear ratio vs prop pitch? Example, adding power to a not ideal ratio (too steep) could be overcome by propping with a longer pitch... But is there some issue that limits this? Cavitation or something? Otherwise they wouldnt sell other gear ratios I guess ?
  20. GN7 On the Dyno
    Very good read on the subject. Increasing CR vs boost pressure
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