You're best guess please.

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Outasite

Outasite

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Replacing my 671 blown 340 (around 450hp) With a new 408. Hoping you fellas can tell me what to expect. The build is 99 magnum block,.030 over decked to 9.574 line honed,studded with Hughes girdle.eagle forged crank,Scat H beams wth ARP 2000 bolts.Icon 34cc dish pistons,under Cometic .050 MLS gaskets.Ontop is out of the box Trick flow 190s,and Harland sharp 1.6 rockers.
Blower spec hyd roller cam from Bullet,114 degree lobe center at around 590 lift,and moral lifters.Blower just fresh from a Dyer rebuild (671) running @ 6% overdrive should net 9-10 PSI compression ratio is 9.2 static and dynamic is 7.15 The only dyno is 90 miles and$1500 per day and was told "we don't do Mopars" best guess on HP Thanks!

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With 9.2 compression and no blower I'd say the engine might get to 325 hp. With the somewhat modest 10 psi I'll say 525 hp. But you could easily push up the boost another 5 psi and get well into the 600s. Since this seems to be a well built engine with the right combination of parts, you could turn up the boost and it would still live. Have you considered using methanol for fuel to keep the boost air temp down and run more boost? How will you be using this engine? Can we see the car?

Are you planning on testing it somewhere? Can you find another dyno shop with a mopar bellhousing or maybe take it to the track sometime?

Regardless of how it turns out, nothing sounds as good as a roots type supercharged engine like yours!
 
MinnesotaMopar said:
With 9.2 compression and no blower I'd say the engine might get to 325 hp. With the somewhat modest 10 psi I'll say 525 hp. But you could easily push up the boost another 5 psi and get well into the 600s. Since this seems to be a well built engine with the right combination of parts, you could turn up the boost and it would still live. Have you considered using methanol for fuel to keep the boost air temp down and run more boost? How will you be using this engine? Can we see the car?

Are you planning on testing it somewhere? Can you find another dyno shop with a mopar bellhousing or maybe take it to the track sometime?

Regardless of how it turns out, nothing sounds as good as a roots type supercharged engine like yours!
Click to expand...
99% street.pump gas only.super sniper 2X4, 1 7/8" headmans into 3" to rear bumper.64 valiant 2800# Dana44 4:27 changing to 3:54.

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I think there are programs for that. I had a coworker who would input the cam, etc and his program would estimate it. I'm guessing that is why @rumblefish360 may be asking...or he is a genius with no need for such a tool!
 
ACME SS said:
I think there are programs for that. I had a coworker who would input the cam, etc and his program would estimate it. I'm guessing that is why @rumblefish360 may be asking...or he is a genius with no need for such a tool!
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That’s the primary reason for the super sniper setup.Very programable. Complete timing control boost retard,Air fuel ratio control,cooling fan etc. I’m 71, learning curve may be a little testy for me! The book is pretty thick! But from what I’m reading a decent tune can be done “on screen”
 
408 with trick flow heads is probably around 500 hp itself plus you'd think 150-200 hp for the blower, which be 650-700 hp.
 
Typically take hp NA then double for every atmosphere (~14psi) of boost. Roots blowers add a bunch of heat but they are cool. So 500hp NA and add 14psi should get you up to 750hp for easy rough numbers. Should be able to math it out, make a ratio to get close
 
Thanks to all that have replied.My old setup was super reliable.Want this to be similar .I want to keep it below the point of block issues!
 
Just for comparison this racer brown,is in my current 340 .Jim came up with this in 95, it's been great!

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ACME SS said:
I think there are programs for that. I had a coworker who would input the cam, etc and his program would estimate it. I'm guessing that is why @rumblefish360 may be asking...or he is a genius with no need for such a tool!
Click to expand...
NOT a genius! Smarty pants maybe…..
Though I will say my dyno guessing attempts here have been, well, not so good.

A desk top dyno that sent a bad program, if your honest and accurate in inputting the specs needed.
 
Your engine is very similar to mine but you have more cubes, 340 to 408 and a little more static compression. Your cam is similar but not exactly the same as mine. Mine was a custom job by Steve Morris Racing. All of that being said I have between 650 and 700 Hp so I am going to guess you will be between 700 and 750 HP. A stout piece but well within what a block can take. I started out with my timing locked at 28 degrees and worked it up to 31 degrees. My 340 seems to love that and I am hesitant to advance it any more as like you, I wanted some dependablity as well. That is going to be a fun ride for sure.

Jack
 
Was it overdriven 6% on the 340 and made 9-10psi? If so it won’t make the same boost on a 408 with better heads. Likely 6-7 psi. With your cam, heads and 408 on 10 psi I’d guess 630-670 for a dyno number.
 
Jack,thanks for the reply.Was looking at my paperwork on my 340 today.I built that in 1995 and have had -0- issues with it.Not a ton of miles, but two tons of fun.Kept it to 6/7 psi and just never touched it.what kind of boost do you run,and do you have manifold air temp.I’m going 6% over so thinking I mite want to look at temp in the plenum.Oh, timing back then didn’t understand that boost don’t like timing.And was running as much as 35% total,but also a fair dose of 100LL most of the time.
Bob
 
TT5.9mag said:
Was it overdriven 6% on the 340 and made 9-10psi? If so it won’t make the same boost on a 408 with better heads. Likely 6-7 psi. With your cam, heads and 408 on 10 psi I’d guess 630-670 for a dyno number.
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Was 6% under on the 340 @6-7 Going 6% over on 408 hoping for near10
 
TT5.9mag said:
Was it overdriven 6% on the 340 and made 9-10psi? If so it won’t make the same boost on a 408 with better heads. Likely 6-7 psi. With your cam, heads and 408 on 10 psi I’d guess 630-670 for a dyno number.
Click to expand...

Outasite said:
Jack,thanks for the reply.Was looking at my paperwork on my 340 today.I built that in 1995 and have had -0- issues with it.Not a ton of miles, but two tons of fun.Kept it to 6/7 psi and just never touched it.what kind of boost do you run,and do you have manifold air temp.I’m going 6% over so thinking I mite want to look at temp in the plenum.Oh, timing back then didn’t understand that boost don’t like timing.And was running as much as 35% total,but also a fair dose of 100LL most of the time.
Bob
Click to expand...
I don't know exactly how much I am underdriven because it's been a while since I changed my pulleys. ( I have 5 of them) It is underdriven but close to 1 to 1 (maybe 41-40 pulleys) and I am making 9 lbs of boost. My "X" heads are ported as far as they can go with 2.02 valves. I had changed my top pulley to get 12 lbs once. That lasted about and hour before I broke my harmonic balancer. Sure was a fun hour though. lol Live and learn.

Jack
 
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