A  step by step build up to building a Hyper-Pak.
 

First clean  the the block and check for core shift as well as cylinder wall thickness. The best way to check for core shift between the combustion chamber and cylinder bore "as much as 0.020-0.030 inch can be caused by manufacturing"

Mount the head to an empty block and outline the cylinder bores with a scratch awl  another thing to use is machinist dye for obvious core shifts. If possible you can use an abrasive disc to get the protrusions out. The slant six head is extra thick, therefore the heads can be safely milled up to 0.100 inch which will give your compression a dramatic boost from 8.4 to 9.2:1 ratio.

The crankshafts from 1961-1968 used a small pilot 1.960 od 1.530 id. They were a forged casting as well. Crankshafts after 68-76 used the large pilot 2.160 od 1.805 id and are all forged castings. Crankshafts after 76 were all cast crankshafts and are not recommended for high R.P.M engine builds.

Connecting rods from 1961 to pre 1976 are all forged and are excellent for a hp build up. A lot of horsepower can be obtained by installing oversize valves and blending the bowl areas. Use the bigger valves 1.70 intake and 1.44 exhaust which will give you roughly 5% over the stock valves. 1.62 intake and 1.36 exhaust. on the camshaft you can use the 71-76 camshafts which have a 244 duration and a lift of .406 intake and .414 exhaust. The settings for this camshaft are .010 intake and .020 exhaust.

You can use a 464/276 duration camshaft. Remember that when choosing the more radical cams anything over the 280 duration will require the pistons to be notched.

The valve springs  are Mopar Performance part # p4120249; these are single springs with a damper installed ht.1.67/1.70 od 1.50' wire diameter is .206 lift range for these springs are .430/.500" and are chrome.

Use a water cooled 4-barrel the original Hyper-Pak intake will not clear the power booster and master cylinder in the Dodge pick ups that have disc brakes.

The carb Holley 4 barrel 4160 series which is recommended for engines in the 150-300 displacement; it has a 390 cfm rating which will work well with street and strip usage.

Use a Chrysler big block lower gear and chain and ordered a sealed power top gear pn-223-338. A windage tray  will free up close to 15 extra horsepower. A  high-volume oil pump will give you 50 psi at all times which is more then adequate and well worth the money.

For the exhaust use split headers with dual 2/1/4 inch pipes that feed into Dynomax glass-packs. The A-833 4-speed backs the Hyper-Pak along with an 8/1/4 3:91 sure-grip.