Generation IV Internal Engine - Hp numbers for 438 ci. L92

I would like to hear some HP numbers for the following engine:

LQ9 2000 yr bored .10 over
eagle 4.200 in. crank, rod journal turned down
eagle 6.125 Honda rod journal
Weisco 11.70 compression
WCCH L92 heads ,compcams LSR valvesprings
Comp cams LSR 251/267 .624/.624
Comp cams short travel lifters
Yella terra 1.8 shaft mounted rockerarm
Elderbrock L92 intake Dr. J ported
Race Deamon 825 annular boosters

570-580 RWHP...M6

But don't you need at least 4.1" bore to use L92 heads?

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4.1=ls7 4.0=ls3

4.1=ls7 4.0=ls3

LS7 = 4.125 stock....right?

4.0 = LS3.........but if he goes .10 over to 4.010, will the L92 head work?

If he's doing a 438ci and using a 4.2 stroke, the bore has to be about 4.060 to make 435ci.

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570-580 RWHP...M6

But don't you need at least 4.1" bore to use L92 heads?

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4" bore is what is needed.

4" bore is what is needed.

Oh OK.

Your compression height on your piston is going to be very small. Hope you don't plan on any power adders. I would think you would need to run an aftermarket block for that much stroke.

335 hp

LS7 = 4.125 stock....right?

4.0 = LS3.........but if he goes .10 over to 4.010, will the L92 head work?

If he's doing a 438ci and using a 4.2 stroke, the bore has to be about 4.060 to make 435ci.

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LS3/L92 = 4.065-4.068 bore - maybe what you were trying to say?
or
LS2 = 4.00 bore?

LS3/L92 = 4.065-4.068 bore - maybe what you were trying to say?
or
LS2 = 4.00 bore?

A stock LS2 is 4" bore? oh, ok.

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Your compression height on your piston is going to be very small. Hope you don't plan on any power adders. I would think you would need to run an aftermarket block for that much stroke.

Yes the compression height would be shallow at 1.015 but there are many SBC engines running around with 1.000" pin height to use a 4.000" stroke and 6.000" rod in a stock 9.000" deck height block. The typical engine combo would be a 427-434cid. I understand the ring life will be shortened and oil control reduced. But I have never built that combo so I cannot say from experience.

Many will say not to use more than a 4.125" stroke with a 6.0L block due to the cylinder length. I wonder if anyone has some experience with a 4.200" stroke and one of these blocks. The smaller 1.888 Honda rods will certainly help with block clearance and rod to cam clearance. I would strongly consider the fact that ALL the heat treating of the crank journal on the rod throws will be gone when it is turned down .212". The crank should be re-heat treated after it is turned down. But that will become an expensive crankshaft once you consider the work to have it turned down and then heat treated again. Not to mention most will think it is crazy to spend that kind of money on an Eagle crankshaft.

The cam tunnel is not open as such to warrant any issue from the rods hitting them like on the regular SBC engines. Translation: no small base circle cams just because you want to use a long stroke/rod or an offset rod ratio.

I would def go with something of better repute for that build than an eagle IMO. IIRC we can get callies to grind the rod journal and rough or total balance the crank before it is shipped.

The cam tunnel is not open to warrant any issue from the rods hitting them like on the regular SBC engines. Translation: no small base circle cams just because you want to use a long stroke/rod or an offset rod ratio.

I would def go with something of better repute for that build than an eagle IMO. IIRC we can get callies to grind the rod journal and rough or total balance the crank before it is shipped.

Any comment on the cylinder length John?

What would you call that underside area beneath the cam in an LS block anyway?

Man it is hard to say. I would say the amount of piston coming out and the possible amount of rock from that iron block would more than shy me away from trying to do it without some sleeve to make sure itll work right. Thats alot of real estate

If i were to guess on parts, i would call that the arm pit...lol.

Man it is hard to say. I would say the amount of piston coming out and the possible amount of rock from that iron block would more than shy me away from trying to do it without some sleeve to make sure itll work right. Thats alot of real estate

I would be hesitant as well just based on the ground work laid out by others that have done the longer 4.125" stroke combos in stock GM blocks. Now assume we are talking about a block with a longer sleeve/cylinder in it, what would you say is the max stroke would be before we see interference with that "underside" arm-pit area below the camshaft tunnel? And let us assume stock LS/SBC rod journals of 2.100".

(Don't mean to hi-jack here but this discussion may be relevant to the build.)

Had to edit my post. The tunnel is open but not as such that is causes a problem like the SBC did when say using a long rod 406 (that is what i meant). but as in the LS7/LSX block you could run up to a 4.250 stroke (we build a 468 LSX with a 4.185 * 4.250 stroke) and not have a problem with the standard large pin 2.100 rods. If you want to run more or are having questions, then maybe the small journal would be better fitted but it is just at 2" or the honda journal then. Realistically anything longer than that would take the warhawk probably or the RHS (if its out) the Dart Billet or the LSX tall deck (when it comes out). To try and build that many more CI out of a standard deck is reaching the limits of what even the LSX can do at the moment

Had to edit my post. The tunnel is open but not as such that is causes a problem like the SBC did when say using a long rod 406 (that is what i meant). but as in the LS7/LSX block you could run up to a 4.250 stroke (we build a 468 LSX with a 4.185 * 4.250 stroke) and not have a problem with the standard large pin 2.100 rods. If you want to run more or are having questions, then maybe the small journal would be better fitted but it is just at 2" or the honda journal then. Realistically anything longer than that would take the warhawk probably or the RHS (if its out) the Dart Billet or the LSX tall deck (when it comes out). To try and build that many more CI out of a standard deck is reaching the limits of what even the LSX can do at the moment


Good stuff John! Thanks for the info.:cool:

I would like to hear some HP numbers for the following engine:

LQ9 2000 yr bored .10 over
eagle 4.200 in. crank, rod journal turned down
eagle 6.125 Honda rod journal
Weisco 11.70 compression
WCCH L92 heads ,compcams LSR valvesprings
Comp cams LSR 251/267 .624/.624
Comp cams short travel lifters
Yella terra 1.8 shaft mounted rockerarm
Elderbrock L92 intake Dr. J ported
Race Deamon 825 annular boosters

I don't think those heads are that good on such a small bore either but they could work. Your other stuff seems alright. You probably can't really make a piston work in that deal for any kind of street type engine though and no power adders.