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Hey Barry

old man on the lake

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Is it possible to build over 500 HP with gen iv and 781 heads on pump gas with decent Tq at 3000 RPM . Buddys wife and kids got him on a budget so we are trying to figure it out.
Application is Schiada 19 w/ t400 ski/lake dealeo.
What would you suggest?
Thanks in advance,appreciate all your threads on RDP.
 

djunkie

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I don't mean to speak for Barry but that should be totally doable. May not be able to run on 87 octane but with 91 it should be possible.
 

obnoxious001

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Is it possible to build over 500 HP with gen iv and 781 heads on pump gas with decent Tq at 3000 RPM . Buddys wife and kids got him on a budget so we are trying to figure it out.
Application is Schiada 19 w/ t400 ski/lake dealeo.
What would you suggest?
Thanks in advance,appreciate all your threads on RDP.
Sure,, 500 HP should be relatively easy.

I would suggest something in the lower 9-1 compression range,, forged pistons, maybe KB Icon or Probe to help with the budget. A mild flat tappet cam should make that power and help keep costs lower as well.
 

old man on the lake

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Thanks Barry.
Intake ?
Cam ?
Carb. ?
Head clean up ?
Block is clean @ + .30
Might need to get crank. Stroke ?
Exhaust will be Harman Logs

Thanks again.
 
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RaceTec

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Sure,, 500 HP should be relatively easy.

I would suggest something in the lower 9-1 compression range,, forged pistons, maybe KB Icon or Probe to help with the budget. A mild flat tappet cam should make that power and help keep costs lower as well.
Don't forget our RDP discount! We can help you out for sure... I might even have a set of our old stock that I can give you a great deal on once you figure out your combination...
 

obnoxious001

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Thanks Barry.
Intake ?
Cam ?
Carb. ?
Head clean up ?
Block is clean @ + .30
Might need to get crank. Stroke ?
Exhaust will be Harman Logs

Thanks again.
A good dual plane intake,, Performer RPM Airgap or similar should work well to 5500 rpm, which is a good limit for a BBC that you want to last a long time.

I can get a camshaft ground for you once you have all the parameters.

Carb,, probably 750 CFM Holley is going to be fine, unless you want to turn higher rpm. What have you already got?

You shouldn't have to do head work if you are trying to keep it cheap,, and aren't looking for every last horsepower. Stainless steel valves would be recommended.

If you have to buy a crank, then possibly rethink your combination and build a stroker,, 489 cu in is what you get with the .030" and a 4.250" stroke, but then you have kind of tossed the budget out the window,, so maybe just a good used steel 454 crank.

If you need to run the Harman logs, as in, already have them, can't afford to buy others,, make sure that the risers and exhaust tips are for 3 1/2" hose, not the smaller 2 7/8"
 

old man on the lake

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Barry if I can con him into a stroker how much more torque should be expected?
We have a 750 so thats great.
Looking at cranks, it seems that 4.25 Scat are the same $. Rods seem a little more but not much.
Barry it seems a way to get added HP and Torque for not much more money.
Do the 781s have enough to support 489" ?
Trying to build this motor with $2500 in new parts.
Have blk,heads,carb,exhaust( they are the 3" )alternator,starter,linkage,ignition.
Need rotating asseb.bearings,gaskets,intake,valves,springs,keepers,cam,lifters.

Am I dreamin?
 

obnoxious001

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Barry if I can con him into a stroker how much more torque should be expected?
We have a 750 so thats great.
Looking at cranks, it seems that 4.25 Scat are the same $. Rods seem a little more but not much.
Barry it seems a way to get added HP and Torque for not much more money.
Do the 781s have enough to support 489" ?
Trying to build this motor with $2500 in new parts.
Have blk,heads,carb,exhaust( they are the 3" )alternator,starter,linkage,ignition.
Need rotating asseb.bearings,gaskets,intake,valves,springs,keepers,cam,lifters.

Am I dreamin?
If you are really trying to stick to $2500 in parts, better make yourself a list and add up everything. I don't think you can do the stroker on that budget unless you use a cast crankshaft and I beam rods. Not my usual choice but could work for a mild lake boat at reasonable RPM, and possibly still get away OK with the 750 carb.

It's only a 29 cubic inch gain, at one horsepower per inch,, 29 HP?
 
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