Big bore 393ci
Thread Starter
TECH Senior Member
Joined: Mar 2004
Posts: 14,620
Likes: 17
From: BFE
Big bore 393ci Ok, call me nuts 
But being the anarchist that I am, I am contemplating doing the following:
LSX block (decked .015, 9.240)
4.155 bore
6.125 callies rods
3.622 nitrated crank
Wiseco pistons (1cc reliefs)
LS7 heads
LS7 intake
Custom cam
Target>7200 rpm with 200>250 shot N2O (dual stage)
Shooting for 700>750rwhp
393cid/6.44 L
Has anyone done something similar, what were your results?
What do you think? (besides that I'm nuts, obviously)
Mark
But being the anarchist that I am, I am contemplating doing the following:
LSX block (decked .015, 9.240)
4.155 bore
6.125 callies rods
3.622 nitrated crank
Wiseco pistons (1cc reliefs)
LS7 heads
LS7 intake
Custom cam
Target>7200 rpm with 200>250 shot N2O (dual stage)
Shooting for 700>750rwhp
393cid/6.44 L
Has anyone done something similar, what were your results?
What do you think? (besides that I'm nuts, obviously)
Mark
It will allow you to unshroud the heads to let them breath better, thus taking full advantage of the bigger bore. In addition to allowing for more stability in the higher revs. Theoretically.
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From: Western Burbs of Detroit
Big bore, standard stroke, HIGH RPMS, + Nitrous ?? Sounds wicked.................................
Mark your planned motor sounds like its going to be sick !! I'm sure with the way you match things up she should make 500 on motor or close to it. Best of luck.
Mark your planned motor sounds like its going to be sick !! I'm sure with the way you match things up she should make 500 on motor or close to it. Best of luck.
Thread Starter
TECH Senior Member
Joined: Mar 2004
Posts: 14,620
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From: BFE
Yes 500 should be atainable.
This is for a drag project on a 2950 lbs 00 Z28 shell.
A3, TH400, 8.8 dif (Ford custom), stall ???? (that will require professional advice)
I have to keep factory block (no Warhawk etc..), 1 power adder (multi stage allowed, no trans brake, no wheelies, dif in stock mounts (no 4 link), 10.5 tire (on ground patch).
Anything over 700 on juice should allow me low 9s or high 8s (after dialing).
60' is a bitch because it has to be dialed in perfect in order not to lift too much.
That is why I'm choosing this combo, high rpm to use more of the band a bit longer.
I am trying to lighten that car as much as possible without any radical tricks. I have to keep full trim inside (1 seat, carpet, original door trim, aftermarket guages allowed) but all else coming out.
I have to check on some things, like head studs length (since block will be decked to 9.240 deck to reach 0 piston deck height), gaskets (Cometics and I are gonna have some fun again), custom pushrods (that is going to be a PIA), keeping stock LS7 rockers (geometry is going to have to be spot on).
All in all, lots of little details, and budget is limited (as usual). It is going to keep me busy for this year at least (I'll be doing a lot of garage racing).
This is for a drag project on a 2950 lbs 00 Z28 shell.
A3, TH400, 8.8 dif (Ford custom), stall ???? (that will require professional advice)
I have to keep factory block (no Warhawk etc..), 1 power adder (multi stage allowed, no trans brake, no wheelies, dif in stock mounts (no 4 link), 10.5 tire (on ground patch).
Anything over 700 on juice should allow me low 9s or high 8s (after dialing).
60' is a bitch because it has to be dialed in perfect in order not to lift too much.
That is why I'm choosing this combo, high rpm to use more of the band a bit longer.
I am trying to lighten that car as much as possible without any radical tricks. I have to keep full trim inside (1 seat, carpet, original door trim, aftermarket guages allowed) but all else coming out.
I have to check on some things, like head studs length (since block will be decked to 9.240 deck to reach 0 piston deck height), gaskets (Cometics and I are gonna have some fun again), custom pushrods (that is going to be a PIA), keeping stock LS7 rockers (geometry is going to have to be spot on).
All in all, lots of little details, and budget is limited (as usual). It is going to keep me busy for this year at least (I'll be doing a lot of garage racing
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hell yeah that sounds sick,with a normal weight car it wouldnt be as nice,but if your under 3000lbs then that will be real nice.What about making it a solid roller and hitting close to 8k rpms??
Thread Starter
TECH Senior Member
Joined: Mar 2004
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From: BFE
I considered that, but it is not necessary and I would rather not be adjusting lash on a regular basis. Hydraulic is more maintenance friendly. I do not have a full shop. Just a tiny garage.
If I was going NA, that would be an option, but with juice, 7200rpm is plenty.
If I was going NA, that would be an option, but with juice, 7200rpm is plenty.
FormerVendor
Joined: Nov 2001
Posts: 3,065
Likes: 6
From: Houston, Tx.
Done many deals like that for people that had to stay at a certain CID or lower for whatever reason or were trying to save money etc. You will make good power but less than a larger engine. Other than loosing power everywhere there is no real downside and the upside is you can make a much stronger NOS piston the more room you have for taller CH on the piston.
Bore and stroke combos won't really change your rpm band at all at this level though but the valvetrain and heads and intake will for sure. If you want more rpm you need an intake and heads and valvetrain combination that will do it before the bore and stroke even matters. We have 4.250 crank deals turining 7500 rpm with the FAST 92 manifold and the stock strokes don't turn any higher before loosing power but they do make a whole lot less power.
Bore and stroke combos won't really change your rpm band at all at this level though but the valvetrain and heads and intake will for sure. If you want more rpm you need an intake and heads and valvetrain combination that will do it before the bore and stroke even matters. We have 4.250 crank deals turining 7500 rpm with the FAST 92 manifold and the stock strokes don't turn any higher before loosing power but they do make a whole lot less power.
TECH Regular
Joined: Sep 2005
Posts: 453
Likes: 0
From: 415 Northern CA
A very unique motor combination indeed. After a season or two, you know you will start to think about punching it out to attain more cubes. That's the great thing about having the iron LSX block though, going as big or small as you want. The 393ci will definately rev quickly with that bore/stroke combo in there.
Thread Starter
TECH Senior Member
Joined: Mar 2004
Posts: 14,620
Likes: 17
From: BFE
Done many deals like that for people that had to stay at a certain CID or lower for whatever reason or were trying to save money etc. You will make good power but less than a larger engine. Other than loosing power everywhere there is no real downside and the upside is you can make a much stronger NOS piston the more room you have for taller CH on the piston.
Bore and stroke combos won't really change your rpm band at all at this level though but the valvetrain and heads and intake will for sure. If you want more rpm you need an intake and heads and valvetrain combination that will do it before the bore and stroke even matters. We have 4.250 crank deals turining 7500 rpm with the FAST 92 manifold and the stock strokes don't turn any higher before loosing power but they do make a whole lot less power.
Bore and stroke combos won't really change your rpm band at all at this level though but the valvetrain and heads and intake will for sure. If you want more rpm you need an intake and heads and valvetrain combination that will do it before the bore and stroke even matters. We have 4.250 crank deals turining 7500 rpm with the FAST 92 manifold and the stock strokes don't turn any higher before loosing power but they do make a whole lot less power.
So I figured trying to get the most with what I have.
I am not trying to brake any records, just "consistant" mid 9s will please me.
Interesting, you must be getting a real good deal on the LSX block then as well. Its like $2000 for an Lsx block. You could build bigger cubic inches for less money going in a different direction and it would also be less weight as well (all be it not much less..LOL). Good luck with the build it will be interesting to see your results.
Thread Starter
TECH Senior Member
Joined: Mar 2004
Posts: 14,620
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From: BFE
You are talking 408? Yeah i could do that. I already have a 370cid, but it means I would need heads to make the power I want and besides, big bore is more unique 
and I would be just a crank away from more cubes later on.
Some guy here wrecked his 07 Z06, so we vandalised/salvaged a few parts. Buddy of mine wanted the block, I zapped the heads and intake.I paid 1600 Dirhams (420$)
I wanted the whole motor, but sometimes you just have to settle for what you can get
and I would be just a crank away from more cubes later on.Some guy here wrecked his 07 Z06, so we vandalised/salvaged a few parts. Buddy of mine wanted the block, I zapped the heads and intake.I paid 1600 Dirhams (420$)
I wanted the whole motor, but sometimes you just have to settle for what you can get
You are talking 408? Yeah i could do that. I already have a 370cid, but it means I would need heads to make the power I want and besides, big bore is more unique and I would be just a crank away from more cubes later on.
Some guy here wrecked his 07 Z06, so we vandalised/salvaged a few parts. Buddy of mine wanted the block, I zapped the heads and intake.I paid 1600 Dirhams (420$)
I wanted the whole motor, but sometimes you just have to settle for what you can get
and I would be just a crank away from more cubes later on.Some guy here wrecked his 07 Z06, so we vandalised/salvaged a few parts. Buddy of mine wanted the block, I zapped the heads and intake.I paid 1600 Dirhams (420$)
I wanted the whole motor, but sometimes you just have to settle for what you can get
Sounds like a sweet build man, should make very good power on the squeeze.
What are the other cars (the fastest ones) in the class running now? Its always to shoot for faster than them and detune it a little bit.
Good luck on the build man.
What are the other cars (the fastest ones) in the class running now? Its always to shoot for faster than them and detune it a little bit.
Good luck on the build man.