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Thread: big block vs. small block

  1. #1
    auto
    Ok, now that we had such fun with oil pans, let's try this one. I've noticed that nearly all flats run big blocks, usually the more brutal the better. But I've run into a few guys who run small blocks and really like them - better throttle response, they say. They can also be built to make as much power an anyone with grey hair wants. So what's the consensus?

  2. #2
    blowngas
    auto:
    Ok, now that we had such fun with oil pans, let's try this one. I've noticed that nearly all flats run big blocks, usually the more brutal the better. But I've run into a few guys who run small blocks and really like them - better throttle response, they say. They can also be built to make as much power an anyone with grey hair wants. So what's the consensus?It's really a matter of preference---I have a brotherinlaw that has a light mid sixtys stevens with a 327 chevy, 4 bl, 3 blade prop, and he uses it for a ski boat and cruising when no chop, mainly skiing--great boat, all orginal,fun, runs somewhere around 50s--I have a mid seventies heavy hull hondo that will beat u to death in any kind of chop--so we turned it back into the race boat it originally was---(Blown on gas BBC)--and for something different, you can build a 400+ cu in small block that in a very light (race boat) run with the big blocks (pro-mod 7.0 bracket)--its all a matter of choice and the option is up to u----

  3. #3
    FLYTE RISK
    Go to www.dragboats.com or njbaracing.net.. look at results for the 8.0 850 bracket class. Color me gone TomHolm donovan small block or iguess ya could call it a small block.. that boat FLIES litterally sweet ride........ Much cheaper to build a small block but what you gonna do withit?????

  4. #4
    HM
    I have a blown 350 Chevy in my 18' 72 Mandella Long Deck. It dyno'd at 758 HP and 638 lbs of torque (torque is is noticeble higher now that I am running with the timing locked out). The boat will do easily over the 100 mph mark now. Redline is 7200 RPM and torque peaked at 5290 RPM. You will notice the RPM's are high, and will be significantly higher than a big block with similar HP and torque. These much higher RPS numbers mean lower engine life in the long run (or even the short run!).
    If I were to do it over again, I would go big block. I think big blocks give the v-drives the torque curve that is more easily attained than the small blocks, and have a more likely chance of running pump gas, and all at lower RPM's. I have to run race fuel (or at least av gas with the boost retard adjusted appropriately).
    Not neccesarily cheaper to own a small block. I have about $30K in mine - blue printed and dyno tuned.
    My opinion is in regards to recreation boating. Don't get me wrong - I love my little blown mouse and am very happy with the performance. I think I would be more secure in the life of a big block over the small block.

  5. #5
    LVjetboy
    So what about the weight difference Holy? How much more hp (and life reducing stress) would you need to add to that BB to get the same speed you run with a SB? Considering that adding an extra 200 lbs is like adding another pax?
    jer

  6. #6
    Kurtis500
    Who cares about the chevy stuff...buy a HEMI!!
    I think you will find that the BBC has the boat hardware market by 10 to 1 over any other motor. Including the small block. You can find the parts and replacement parts you need much easier, and in variety. I have a 383 CHrysler in my flat and can tell you finding parts like headers or mounts is a little more difficult to find.

  7. #7
    Jordy
    LVjetboy:
    So what about the weight difference Holy? How much more hp (and life reducing stress) would you need to add to that BB to get the same speed you run with a SB? Considering that adding an extra 200 lbs is like adding another pax?
    jer If you think about it in the scheme of things, 200lbs is just adding another person. Granted it's a lot of weight if you're racing 1/4 mile and trying to cut 1/100th's off your time, but as a lake boat I'd think it would be insignificant. Hell, one of the fastest runs I've ever had in my boat was with 3 people in it (we almost broke 60 wink ). Just my $.02

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