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Discussion Starter #21
Well I have ended up finding some! Wish I could have done a back to back on this engine on my own dyno but the original engine combo was built and dyno'd elsewhere, was at 600hp according to the original dyno sheet (408ci). I will be adding the exhaust plates and fixing up the chambers as they were very average and hope to pick up 30-50hp with the same combo (solid roller). And now have another customer interested to add intake and exhaust tongues to a low rpm 408 hyd roller 4V deal that I built and dyno'd that could be a very interesting back to back comparison if he decides to go ahead and not go to 3vs.
 

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Discussion Starter #22
I actually only seen gains with tongues on lower rpm stuff. On 6000 and up if ported i never seen anything on dyno in terms of gains. I know the actual prostock plate was said to gain 20 hp at 8500 plus rpm
Interesting, was that with intake and exhaust tongues or just one or the other?
 

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You could be right. We made plates for two bronco projects i did. One was 357 cubes the other was 408. Both seen gains with 1 3/4 tube size header on dyno and also thats the only factory header built to fit bronco. So we made a plste that transitions nice from the 4v exh flange to the 2v 1 3/4 size. Worked very well. View attachment 107841 Note the plate between header flange.
The Sandersons on my 414 bronco are 1 7/8"
 

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89, but it has 10" lift, about half frame and half body so gave more room for 400 and headers to fit. These are shorty headers also
 

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Ok that makes sense. These are 79 broncos. Could get upright headers thats it. The 357 seen about 11 hp gain with small header over 1 7/8. But it peaked at [email protected] Little pump gas unit for my buddies daughter.The 408 in pic was my sons. Its a 408 based on m motor. It made [email protected] and made about 8 hp less peak with small tube. However it picked up about 15 through midrange and gave it a better avrg. So for mud truck we figured it work better.
 

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Well I have ended up finding some! Wish I could have done a back to back on this engine on my own dyno but the original engine combo was built and dyno'd elsewhere, was at 600hp according to the original dyno sheet (408ci). I will be adding the exhaust plates and fixing up the chambers as they were very average and hope to pick up 30-50hp with the same combo (solid roller). And now have another customer interested to add intake and exhaust tongues to a low rpm 408 hyd roller 4V deal that I built and dyno'd that could be a very interesting back to back comparison if he decides to go ahead and not go to 3vs.
Was that 600 hp with factory cast 4v quench heads or had they been ported
 

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Discussion Starter #29
Was that 600 hp with factory cast 4v quench heads or had they been ported
They had been ported but the chambers were not done very well the valves were still shrouded, and they had Intake tongues already as well with the Parker Manifold.
 

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Ok that makes sense. These are 79 broncos. Could get upright headers thats it. The 357 seen about 11 hp gain with small header over 1 7/8. But it peaked at [email protected] Little pump gas unit for my buddies daughter.The 408 in pic was my sons. Its a 408 based on m motor. It made [email protected] and made about 8 hp less peak with small tube. However it picked up about 15 through midrange and gave it a better avrg. So for mud truck we figured it work better.
Mine is no where near 550hp. Factory 60 over M block with 400 crank (414), 2 V heads that I cleaned up a bit with untouched edelbrock torker. Using stock 3.55 gear with 40" swampers and auto so trying to get all the low rpm TQ as possible. Works good and gets 12 mpg with a holley and no overdrive. I tried to get the aussi 2v quench heads but gave up.
 
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