Posted By: dannysbee
Biggest low block - 09/24/11 11:57 PM
What is the largest displacement you can get with a stock block low block.
Biggest low block
Posted By: 440Jim
Re: Biggest low block - 09/25/11 12:27 AM
I don't think the question has enough info, application, etc. And although I don't think it is a good idea for most applications, you can with enough effort and risk go pretty big.
I like the 4.250" stroke combos in the low deck. They fit nice with 6.535" long connecting rods and with a 4.375-4.380" bore, 511-512 CID is a nice motor.
I am sure you can fit a 4.50" stroke into the thing, but I don't like it. That would be 540ish CID with the limitations on bore with a stock block.
I like the 4.250" stroke combos in the low deck. They fit nice with 6.535" long connecting rods and with a 4.375-4.380" bore, 511-512 CID is a nice motor.
I am sure you can fit a 4.50" stroke into the thing, but I don't like it. That would be 540ish CID with the limitations on bore with a stock block.
Posted By: dannysbee
Re: Biggest low block - 09/25/11 12:57 AM
Jim it would be a low deck street strip car and trying to keep the torque up and the rpm down, 6500 max on the rpm, 3500 lbs and torqueflite with 3.54 gear. Heads B1 original with 2.25 headers 11 to 1 compression roller cam and NSS Indy ram intake with 800 eddys. I was thinking square 4.375 x 4.375 526 ci.
Posted By: dannysbee
Re: Biggest low block - 09/25/11 02:34 AM
Jim it would be a low deck street strip car and trying to keep the torque up and the rpm down, 6500 max on the rpm, 3500 lbs and torqueflite with 3.54 gear. Heads B1 original with 2.25 headers 11 to 1 compression roller cam and NSS Indy ram intake with 800 eddys. I was thinking square 4.375 x 4.375
Posted By: Cab_Burge
Re: Biggest low block - 09/25/11 03:18 AM
My pump gas 518 C.I. 400 block stroker(4.375 bore with 4.300 stroke) usually makes more torque than HP on pump gas 
Last time on the dyno it had a set of CNC ported Indy 440-1 with a single 1050 Dominator, it made more HP than torque with those heads on it 
B1 will probally flow more than the 440-1 do so you may see similar or better results, my car weighs 3450 lbs with me in it and has gone 10.03 at 133,5 MPH on Oregon non ethanol premuim pump gas with the air cleaner and mufflers on 4.10 gears and 12x29x15 slicks last time out 
don't be suprised if the peak HP is above 6500 RPM and peak torque, depending on the cam grind, is above 5200 RPM BTW, I used a real long rod(6.800 BB Chevy style and sizes) and a very short and lightweight Ross custom piston, 456 grams, piston only I also have a 440 block with a 4.275 stroke it is a high compression race gas brackewt motor with a bunch of good peices, it makes around 71 more HP on race gas with the same heads as the 518 did on pump gas
Last time on the dyno it had a set of CNC ported Indy 440-1 with a single 1050 Dominator, it made more HP than torque with those heads on it B1 will probally flow more than the 440-1 do so you may see similar or better results, my car weighs 3450 lbs with me in it and has gone 10.03 at 133,5 MPH on Oregon non ethanol premuim pump gas with the air cleaner and mufflers on 4.10 gears and 12x29x15 slicks last time out don't be suprised if the peak HP is above 6500 RPM and peak torque, depending on the cam grind, is above 5200 RPM BTW, I used a real long rod(6.800 BB Chevy style and sizes) and a very short and lightweight Ross custom piston, 456 grams, piston only I also have a 440 block with a 4.275 stroke it is a high compression race gas brackewt motor with a bunch of good peices, it makes around 71 more HP on race gas with the same heads as the 518 did on pump gas
Posted By: gregsdart
Re: Biggest low block - 09/25/11 06:31 AM
Quote:
Jim it would be a low deck street strip car and trying to keep the torque up and the rpm down, 6500 max on the rpm, 3500 lbs and torqueflite with 3.54 gear. Heads B1 original with 2.25 headers 11 to 1 compression roller cam and NSS Indy ram intake with 800 eddys. I was thinking square 4.375 x 4.375
If you plan on keeping the revs below 6500 or so, those heads are going to have way too much port area IMHO. Torque won't peak till about 6,000 rpm. My 528 pulls max hp at 6900 rpm with 440-1 heads, which are quite a bit smaller than the B1s. With the combo you propose, you would need at least a 6,000 stall converter to stay up in the power band.
You may make more ultimate hp with the B1 heads at 6500 rpm, but a well built motor with smaller heads will have already beaten you to the stripe by the time you get into the power.
If you plan on sticking with the B1 heads, allow them to rev to at least 7000 to 7200 rpm, and stay at 4.25 stroke for the sake of piston design. the pistons get pretty far out the bottom of the bores, beyond 4.25, and the ring pack starts to get too close to the valve notch, if I recall correctly.
Posted By: 440Jim
Re: Biggest low block - 09/25/11 10:20 AM
Quote:
If you plan on sticking with the B1 heads, allow them to rev to at least 7000 to 7200 rpm, and stay at 4.25 stroke for the sake of piston design. the pistons get pretty far out the bottom of the bores, beyond 4.25, and the ring pack starts to get too close to the valve notch, if I recall correctly.
That was what B1Ken was saying and he ran lots of 4.250" stroke low decks with B1 original heads.
+9.980 block deck height
-2.125 stroke/2 (4.250/2)
-6.535 rod length
-----
1.320 Piston compression height
If your block decks slightly lower, you will need slightly shorter pistons. And with the B1 valve notches, that CH works.
If you really want 572 CID, the RB block is the way to go (Megablock, World, etc).
Posted By: 440Jim
Re: Biggest low block - 09/25/11 10:29 AM
Quote:I am sure it can be done, but...
I was thinking square 4.375 x 4.375
Things get marginal IMO.
B1 head valve layout and piston valve relief with compression height and ring pack location.
More stroke likes a longer rod, to avoid pulling the piston out the bottom of the cylinder at BDC, but uses even less piston CH. So the piston ring pack design will be the part that needs the most work, but calculate all the others (clearing the piston to crank counterweights).
Posted By: 440Jim
Re: Biggest low block - 09/25/11 10:52 AM
Here is the piston to crank counterweight calculation, put in your own dimensions.
Another example:
CWmax = 2(6.535 - 4.375/2 - 0.990/2 - 0.180 - 0.050)
CWmax = 2(6.535 - 2.1875 - 0.495 - 0.180 - 0.050 )
CWmax = 7.24" dia
But the 6.535 rod with that stroke might not be a good idea. And it would need a piston CH less than 1.258"
Quote:
As far as counterweights hitting the piston at the bottom of the stroke, the typical problem is the piston pin boss, ie metal below the piston pin. This thickness varies a lot from one piston design to the next. My Ross 99496 pistons have 0.150", Wiseco K296A35 have 0.220", my Venolias have 0.180". Everything must be checked at assembly for clearance, but this is the math:
CWmax = Counter Weight max dia
Pthick= Piston thickness below the pin
Pin = Piston pin dia
Rod = Rod Length
CWmax = 2(Rod - Stroke/2 - Pin/2 - Pthick - Clearance)
For example:
CWmax = 2(6.535 - 4.25/2 - 0.990/2 - 0.180 - 0.075)
CWmax = 2(6.535 - 2.125 - 0.495 - 0.180 - 0.075 )
CWmax = 7.32" dia
That happens to be the dia of the "cam cut" on a Callies 4.25" stroke crank counterweight for a BB Mopar.
Depending on the bobweight the counterweights can be cut down pretty far. I cut my Callies 4.250" down to 7.14" with a 2185 gram bobweight.
The rest of the counterweight can be larger since it isn't at BDC. My Callies was cam cut from the factory at 7.55"/7.32", but I cut it down to 7.14" dia (round) and balanced at 2185 gram bobweight. The balance shop went between the lathe and the balancer to get this close, don't just use my dia with other cranks and bobweights.
Another example:
CWmax = 2(6.535 - 4.375/2 - 0.990/2 - 0.180 - 0.050)
CWmax = 2(6.535 - 2.1875 - 0.495 - 0.180 - 0.050 )
CWmax = 7.24" dia
But the 6.535 rod with that stroke might not be a good idea. And it would need a piston CH less than 1.258"
Posted By: abodiesonly1
Re: Biggest low block - 09/25/11 01:47 PM
I think Koffel's has or did have a 553" low deck with B1's on it for sale. 
Posted By: 440Jim
Re: Biggest low block - 09/25/11 04:16 PM
Quote:Is that a factory block (4.375" bore) or an aftermarket block (4.500" bore) ???
I think Koffel's has or did have a 553" low deck with B1's on it for sale.
I agree Koffel's is worth talking to about B1 engines.
Posted By: AndyF
Re: Biggest low block - 09/25/11 05:15 PM
Koffel has a low deck, stock block, 553 for sale on their website. $20K price. Motor looks like it was built with some really good parts.
http://www.b1heads.com/engines.html
http://www.b1heads.com/engines.html
Posted By: Twin Turbo Mower
Re: Biggest low block - 09/25/11 08:13 PM
I have a indy block 4.5 bore 4.375 stroke. My old setup had a 6.535 rod. The psiton was as jim said 1.258 compression height. It did work but the pistons did rock at the bottom of the bore. I am going with a longer rod this time around 6.7 and a 043/043/3 ring pack. Pic is of my old vs new piston. The new one is 1.093 compresion height.
Posted By: 440Jim
Re: Biggest low block - 09/26/11 01:48 AM
Quote:Was that with B1 valve reliefs or standard/Indy head valve reliefs?
I have a indy block 4.5 bore 4.375 stroke. My old setup had a 6.535 rod.
As you have found, more stroke should have a longer rod, and that makes the piston shorter and puts the oil ring in the pin. But that is not a show stopper, just a compromise if that is what you must do. The B1 valve reliefs require the top ring farther down, so the ring pack gets tight/lower.
Posted By: joshking440
Re: Biggest low block - 09/26/11 01:49 AM
you can get 572 in a lowdeck
Posted By: 440Jim
Re: Biggest low block - 09/26/11 01:55 AM
Quote:The poster is talking about a stock block, and with a limit of around 4.380" bore, 572" is hard to come by... especially with B1 piston valve reliefs.
you can get 572 in a lowdeck
Posted By: joshking440
Re: Biggest low block - 09/26/11 02:16 AM
didnt see the b1 reference sorry
Posted By: Twin Turbo Mower
Re: Biggest low block - 09/26/11 03:41 AM
The old set was cut for -1 heads the new set is cut for 572-13 heads. But as stated I went with a thiner ring pack for the new set as well. I heard a guy in arizona bought a 4.5 crank and put it in a low deck but I can not remember what heads he used or if the block was stock.
Posted By: Vintage
Re: Biggest low block - 09/26/11 04:05 AM
I like the 4.25" stroke in the low deck. We have one with B1BS heads on it that makes a hair under 800 hp and we only dynoed it to 6700 rpms it was still climbing.I don't think the orig B1s are gonna like the lower rpms as much as a smaller head would. But I do like this engine combo it has gone 9.60s @139.9 shifting at 7000..
But I do like this engine combo it has gone 9.60s @139.9 shifting at 7000..