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Discussion Starter #1
Im looking for some info on what i should build. I have a older weiand 14-71 and a 250 mega blower. Im looking to build two motors, both for the lake and looking to have them as relaiabale as possibale. The 14-71 I know will have to be under driven.I have herd alot of diferent sugestions on 502 vers the 496 for the 14-71, but I would like to get some more inpute on the best rout. If anybody can help, please let me know. Thanks
 

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A 14:71 on a 509 is just overkill for a pleasure setup. It takes a lot of power to spin a 14 then underdriving it to get low boost levels can cause other problems, but only if you spin it very slow. You should build a 540, 572, or 600 for that 14:71 even if its for pleasure use. I think it would be a better combo.
 

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awww, i smell a rat here! lol :)...our friend Cave built a blown motor for his boat & now u dont want to be left behind!!! LOL :)...anyways...IMO go with the 540 or larger for the 14-71 & have fun :)...a 468 for the 250 would work out great :)

FastRat
 

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awww, i smell a rat here! lol :)...our friend Cave built a blown motor for his boat & now u dont want to be left behind!!! LOL :)...anyways...IMO go with the 540 or larger for the 14-71 & have fun :)...a 468 for the 250 would work out great :)

FastRat
We are all Keeping up with Mike Jone's :D

14 71??? Josh you trying to burn stuff up eh.:D:)devil:D I'd go huge if I were to spin a 14 71 on gas. Now are you going Alky?
Not you personally:D The engine...
 

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"It's HONDO, honey"
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awww, i smell a rat here! lol :)...our friend Cave built a blown motor for his boat & now u dont want to be left behind!!! LOL :)...anyways...IMO go with the 540 or larger for the 14-71 & have fun :)...a 468 for the 250 would work out great :)

FastRat
Ya but a 540 is a lot of rotational mass and remember it's bored from the same block as a 396 :)sphss. I vote 454 or 496.

Someone post up the different Gen #'s and the standered Cubic inche displacement that goes along with them. I can't seem to find this?
 

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Discussion Starter #6
Runing gas with intercooler. I have been tolde alky would be easyer on the motor but Im not wanting to fuel up that often and I herd it would be more maintance. Also wondering how big of carbs I would have to use?
Ass far as cave going blown, he just finished his before me. Iev had the blower, just had to finde the boat. Now I can figure out what motor to build. I dont plan on useing the 14-71 to its full potential, its more so for the shock facktor of its size. Trying figure if Im waisting time with such a big blower. Im looking for about 900 to 1000 ponies on gas blowen with intercooler wether its the 14-71 or smaller.
 

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Discussion Starter #7
awww, i smell a rat here! lol :)...our friend Cave built a blown motor for his boat & now u dont want to be left behind!!! LOL :)...anyways...IMO go with the 540 or larger for the 14-71 & have fun :)...a 468 for the 250 would work out great :)

FastRat
Of coures I dont want to be left behinde!:D I think we might have to call are selfs the Low Blowen crew.
 

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Discussion Starter #9 (Edited)
I have a few 454 blocks marck 4's just siting around. That doesn't meem I need to use them. I also have a line on a agen 6 bored 125 over ready for the parts to go in for $350 and I believe a Bowtie or Siemese? 502 or 509 marck 4.
 

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Discussion Starter #10
Also a litle birdy tolde me if i use a big blower it wonte have to work as hard therefore lasting longer.
 

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I have a few 454 blocks marck 4's just siting around. That doesn't meem I need to use them. I also have a line on a agen 6 bored 125 over ready for the parts to go in for $350 and I believe a Bowtie or Siemese? 502 or 509 marck 4.
usuually if your going blown, over .060 on a gm block, I would have the block sonic checked. the blocks vary quite a bit, but I would be skeptical of building at .125 over. LIke said earlier, the amount of powre required to spin a 14-71, far outways the boost youll be looking for in low boost application, therefore too big.. 1000hp on pump gas, I feel youll need to go 540 at least, 600 ci would be better, to get plenty of power w/low octane. carb sizes really depend on the boat size,gears,cubic inch,boost/overdrive,rpm,etc..Good Luck..
 

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Hondo Jet
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I agree on the 540 or bigger suggestion. I started with the same 1000hp goal and the big cubes make it much easier. And if you have E85 in your area you won't need an intercooler. I just got my 540 done and it turned out stronger than I had hoped with a puny little 871. I can just imagine what it would do with a big ole 14 on there:)

 

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just a ski boat with bark
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I agree on the 540 or bigger suggestion. I started with the same 1000hp goal and the big cubes make it much easier. And if you have E85 in your area you won't need an intercooler. I just got my 540 done and it turned out stronger than I had hoped with a puny little 871. I can just imagine what it would do with a big ole 14 on there:)

Cool deal so how much boost were you able to run with the E85 with only 8.3:1 compression. I figured since methanol likes 11.5:1 and ethanol has similar properties to methanol I figured you might go 10-10.5:1 compression.
 

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Hondo Jet
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Whats E85?
E85 is ethenol gasoline blend....~85% ethenol and the rest pump gas.
E85 if you can get it in your area has about 105 octane rating. It likes high compression up to 16:1 I've heard. Ethenol is oxygenated and does not have the same btu's of energy content so you need to use roughly 30% more of it than gas.So to run it youv'e got to set up your fuel system to deliver the goods at all throttle positions...not just the mains.
 

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Hondo Jet
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Cool deal so how much boost were you able to run with the E85 with only 8.3:1 compression. I figured since methanol likes 11.5:1 and ethanol has similar properties to methanol I figured you might go 10-10.5:1 compression.
Well your right on with the comp ratio. I intentionally detuned this motor so that I could put it on pump gas if needed. Well I doubt that's going to happen, all I need to do is shave the heads and I can be at 10:1+
Even with the low static comp. and saftey tune 32 degrees advance pullin 1 degree out per pound of boost. It made good #'s total boost is ~12 pounds. This motor is detuned:)
 

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just a ski boat with bark
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Well your right on with the comp ratio. I intentionally detuned this motor so that I could put it on pump gas if needed. Well I doubt that's going to happen, all I need to do is shave the heads and I can be at 10:1+
Even with the low static comp. and saftey tune 32 degrees advance pullin 1 degree out per pound of boost. It made good #'s total boost is ~12 pounds. This motor is detuned:)
Understand leaving it so you could take some boost out and run pump gas if required. Excellent power for 12lbs or boost. :)devil
 

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Ya but a 540 is a lot of rotational mass and remember it's bored from the same block as a 396 :)sphss. I vote 454 or 496.

Someone post up the different Gen #'s and the standered Cubic inche displacement that goes along with them. I can't seem to find this?
My 540 is a derived from a Gen 6 502 block which is not the same block as a 396 or 454. Different blocks from different years had different cylinder wall thickness. The 502 block (cast with a 8.2L) started its life stock with a 4.467" bore so a 33 thousanths (.033") cleanup brought it to a nice 4.500" safe for that block by design. The 4.250" stroke brought it to 540cid. There are plenty of aftermarket and GM "Bowtie" blocks out there that can safely go big bore (over 4.500"). I like the big bore stroker motor. Lots of Torque!

My opinion: Go Big, keep the compression down and let the blower work.
 
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