BJR Racing
Well-Known Member
First we'll start with a 318 block (rebuilder) as they are plentiful, then we'll get a 360 crank and turn the mains down to 318 specs. this runs about $200.00 to do. We are going to use the factory 6.123 rods, and low compression 318 pistons which are 1.72 compression height. Next we are going to align hone and deck the block to clean and square deck all 4 corners. Price will vary as to your local. This is more info on what to do and not priced as price can vary. So now we have a block that measures 9.570 after decking .030. As most used blocks are generally out .020 to .030 from core settleing and thermal cycles, some may be taller as they are only castings. Now this is where we are 9.570 actual deck height less the rod lenght, and the compression distance, and stroke. Half of 3.58 is 1.79 on stroke.
9.570-1.79=7.780 minus rod lenght of 6.123= 1.657 less the compression distance of 1.72= .063 above the deck. Now we'll take a corteco head gasket of .055 which now we have .008 above the gasket. Or for racing use a .022 mopar gasket and have .033 more compression for a total of .041 above the gasket.
Next we'll go to the heads, for a 349 CI we'll need the 360 heads to get enough port volume and air flow. By my calulations we'll need 166 cc's of port volume and 266 cfms to supply enough air and we'll be useing the 1.88 intake valves and 1.60 exhaust valves to help keep the port velocity up. This is fairly easy to get when mildly ported. As for the chambers they have been in the .095 to .105 in chamber depth stock, at the area where the quench would be. So now we have a positive deck of .041 with the gasket in place, or .008 depending on which gasket is being used. In this case we'll use the thinner gasket so we'll be .041 above the deck. Now the deck is .095 less the positive deck of .041 and we now have a quench of .051 so we'll deck the heads to true them up, generally this takes .010 to .012 so now we have a total quench of .039 to .041 which is what most would like to have as total quench. This now yeilds 12.21:1 this is why this is a race setup, the thicker head gasket will yeild about 11.5:1. If it doesn't take as much to deck the heads or the block then this will change to a lower compression and be more streetable.
Next we'll go to the camshaft, for our example were useing a comp cams .540 /300 drag race cam with 255 @ .050. For this cam the pistons will have to be notched, so we notched them .200 as the pistons are forged and are .400 thick. This is about as far as you can go safely. We'll be useing 1.6 ratio rockers so the lift is .576 but the lash is .026 and we have to subtract .010 for the loss of valve lift due to the grind for mopars. Now we have a actual net lift of .540. So with the valve reliefs we should have .100-.130 valve to piston clearence depending on the gasket thickness.
Next we'll go to the intake manifold, this I leave up to the end user for what they want. But for our application we used the M-1 intake as we had it, from another engine. And we'll top it off with a holley carb 850 cfm with 83 and 88 jets and no power valves.
Next we went to the exhaust as we used hedders the were from dyno-max as they were inexpensive and could get them locally. They were the 1 5/8 street type as we didn't want to get to large as we only have 349 CI's and the bore won't support much more, and neither will the heads.
So now to some this up we have a 318 with a 360 crank and stock rods and pistons of the forged type. Stock type heads with work done and a M-1 intake and a street type hedders. A good cam and valve train and oiling system to support this type of engine. The preliminary tests have shown 578 HP @ 6500 and 507 TQ @ 5000, and 506 FT. lbs. @ 4500. So it has a nice broad torque curve. Even in lessor trim it should still have over 500 HP and 450 in torque and be streetable.
Our cost in this engine with all machine work and parts we have $4,400.00 invested. A cast piston version with less cam would be roughly $500.00 less. Not bad for a engine like this when a crate engine costs about the same and wouldn't have the quality or the power.
But it does show what can be done with available parts and some time if your a do it your selfer, other than machine work. I'm guessing that you may be able to save $1,000.00 or more.
This is for information only and just something that we wanted to play with.
9.570-1.79=7.780 minus rod lenght of 6.123= 1.657 less the compression distance of 1.72= .063 above the deck. Now we'll take a corteco head gasket of .055 which now we have .008 above the gasket. Or for racing use a .022 mopar gasket and have .033 more compression for a total of .041 above the gasket.
Next we'll go to the heads, for a 349 CI we'll need the 360 heads to get enough port volume and air flow. By my calulations we'll need 166 cc's of port volume and 266 cfms to supply enough air and we'll be useing the 1.88 intake valves and 1.60 exhaust valves to help keep the port velocity up. This is fairly easy to get when mildly ported. As for the chambers they have been in the .095 to .105 in chamber depth stock, at the area where the quench would be. So now we have a positive deck of .041 with the gasket in place, or .008 depending on which gasket is being used. In this case we'll use the thinner gasket so we'll be .041 above the deck. Now the deck is .095 less the positive deck of .041 and we now have a quench of .051 so we'll deck the heads to true them up, generally this takes .010 to .012 so now we have a total quench of .039 to .041 which is what most would like to have as total quench. This now yeilds 12.21:1 this is why this is a race setup, the thicker head gasket will yeild about 11.5:1. If it doesn't take as much to deck the heads or the block then this will change to a lower compression and be more streetable.
Next we'll go to the camshaft, for our example were useing a comp cams .540 /300 drag race cam with 255 @ .050. For this cam the pistons will have to be notched, so we notched them .200 as the pistons are forged and are .400 thick. This is about as far as you can go safely. We'll be useing 1.6 ratio rockers so the lift is .576 but the lash is .026 and we have to subtract .010 for the loss of valve lift due to the grind for mopars. Now we have a actual net lift of .540. So with the valve reliefs we should have .100-.130 valve to piston clearence depending on the gasket thickness.
Next we'll go to the intake manifold, this I leave up to the end user for what they want. But for our application we used the M-1 intake as we had it, from another engine. And we'll top it off with a holley carb 850 cfm with 83 and 88 jets and no power valves.
Next we went to the exhaust as we used hedders the were from dyno-max as they were inexpensive and could get them locally. They were the 1 5/8 street type as we didn't want to get to large as we only have 349 CI's and the bore won't support much more, and neither will the heads.
So now to some this up we have a 318 with a 360 crank and stock rods and pistons of the forged type. Stock type heads with work done and a M-1 intake and a street type hedders. A good cam and valve train and oiling system to support this type of engine. The preliminary tests have shown 578 HP @ 6500 and 507 TQ @ 5000, and 506 FT. lbs. @ 4500. So it has a nice broad torque curve. Even in lessor trim it should still have over 500 HP and 450 in torque and be streetable.
Our cost in this engine with all machine work and parts we have $4,400.00 invested. A cast piston version with less cam would be roughly $500.00 less. Not bad for a engine like this when a crate engine costs about the same and wouldn't have the quality or the power.
But it does show what can be done with available parts and some time if your a do it your selfer, other than machine work. I'm guessing that you may be able to save $1,000.00 or more.
This is for information only and just something that we wanted to play with.
