48 degree blocks have some lifters relocated to give the pushrods a more direct path at wider intake spacing of the W7-W9 heads. You cannot use a 48 degree block cam in a 59 degree block and vice versa. Also most W7 - W9 heads have a 15 degree valve angle versus stock and aftermarket LA heads and the 59 degree W2 heads that use a stock 18 degree valve angle so piston to valve clearance may not be optimal. 48 degree W2 heads use the 15 degree valve angle.
You can put the W7-W9 heads on a 59 degree block but have to watch the pushrod angle and the intake port. Some intake port clearance may be needed to be ground for pushrod clearance depending on the rocker intake offset and thickness of the pushrod.
Here is some information from the Shady Dell website.
Shady Dell Speed Shop
Can I put W7, W8, or W9 heads on my factory 340/360 block or 59 degree R3 block?
This is probably becoming my most frequently asked question lately, since the marketplace seems to be flooded with W7/8/9 cylinder heads with MP discontinuing some of the W9s and a lot of used CNC ported heads popping up around the country.
The simple answer is YES. But as we all know, nothing when dealing with Small Block Mopars can be simple. This is going to be a complicated long, drawn out answer, but hopefully you will be able to follow along and I won't have to re-type this on a daily basis.
Let's begin with factory 340/360 blocks as the R3 is a slightly different animal in a few key areas. Any W7/8/9 head will bolt directly to a 10 bolt factory block. They all utilize the standard factory 10 bolt location. However some people get confused because they hear that many W7/8/9s have 18 head bolt holes. MOST do (but not all, some early W7s are 10 bolt only) Those extra 8 head bolt holes do NOT have to be utilized, you can just run the standard 10. However you will need to utilize a specific W7/8/9 longer head stud kit. Your basic factory, or W2/5 head stud kit won't work. As far as head gaskets go, just run your standard 10 bolt, Fel Pro #1008 composite or Cometic 10 bolt LA style Multi Layer Steel head gasket.
So bolting the heads to the block was not overly difficult. The next major obstacle becomes pushrod clearance. The W7/8/9 style heads generally have a much wider intake port runner tract than more normal 59 degree style heads. Generally, with a standard non offset lifter and a standard W7/8/9 rocker arm, you will have pushrod to intake runner wall interference. Certain rocker arms make this interference worse than others. Most Jesel brand rockers for instance will have less offset on the intake rocker than T&D rockers. Obviously the less offset, the more interference with the runner wall. As a general rule of thumb, standard off the shelf T&D rocker arms for W7/8/9 heads will have .550" offset on the intake rocker. All the ones sold through Mopar Performance have .550" offset. Now, T&D will custom make you any offset between .550" and .725", so if ordering new, you can get more offset. Jesel will also build custom rockers with increased offset, however most customers to save money want to use existing rockers that are floating around for sale, and most of these are not wild offset rockers. On everything I have tested to date, a .550" offset intake rocker WILL clear the inner runner wall on any CNC W7/8/9 head with a non offset lifter, but it is VERY close. The outer runner wall has to be notched VERY carefully by hand for clearance, and a 5/16" pushrod is all that will fit. A 3/8" pushrod will break through into the inner runner wall on most heads, and will require an epoxy fix.
To make the situation better, you can use an offset intake lifter. The problem here is that most lifter companies do not cater well to the Mopar crowd when it comes to offset lifters. In fact to the best of my knowledge, no Hydraulic or Flat tappet lifters exist in .904" Chrysler diameter. A couple companies offer an offset Solid Roller lifter, and generally speaking, when you are thinking of running a W7/8/9 head, you are probably already thinking of running a roller anyhow. One of the problems I ran into was the fact that the Comp Cams #892 "Super Roller" lifters don't fit 59 degree blocks? No way, no how. The rivet design on them will not clear the lifter valley area, even with intense grinding. You will most likely hit the water jacket if you try to make these rivets clear. The lifter I am currently recommending that everyone use is a Crane .903" Chevy Solid Roller lifter with a .210" intake offset pushrod cup, and then have Crane install Chrysler "V" Link bars on them. In a factory block, these will allow a 3/8" pushrod to be used. If you want to use a Hydraulic or Flat tappet cam, then I am recommending just use the standard non offset AMC style lifters, and a 5/16" Heavy wall pushrod like a Smith Brothers .080" wall Chrome Moly unit.
Now to make matters worse, W7/8/9 heads do not oil the rockers through the heads, like you are used to on LA style heads. W7/8/9s use pushrod oiling with individual mount rocker arms that are mounted to a large one piece rocker stand in pairs of rockers. The only other option to oil these types of rocker arms is to have spray bars TIG welded in your valve covers and spray bar oil the rockers. This works well with Jesel type rocker arms that spray the rocker arms as it is for oiling, but T&D rockers, which are a fully pressurized rocker body, need modifications to be spray bar oiled. My personal recommendation is to use spray bar oiling as a last resort. Pushrod oiling is the preferred method to oil W7/8/9 rocker arms.
Pushrod oiling rocker arms on a stock factory 59 degree LA engine block can get tricky. If you are using AMC style Hydraulic or Flat tappet lifters, it will work OK. Basically all you are doing is putting on a head/rocker combo that pushrod oils like a Magnum head conversion. The problem comes when you start running large lift solid roller camshafts. You can drop a solid roller lifter right in your factory LA block, and it will get some oil to the top end, but the engine generally will have excessively low oil pressure, and bearing damage will be imminent. There are two ways around this. One is to have your lifter bores bushed, with bronze bushings and run a small .035" oil feed hole in the bushings. The bushings job is basically to act as an oil restrictor, to restrict the amount of oil that is being bled off around the lifter. Also another thing you run into on factory blocks more so than on R3 race blocks, is that the lifter bores have 100,000+ miles on them in most cases, and the bores are usually not located properly in regards to angularity. So bushing the lifter bores corrects both of these problems. The downside? Cost. Having your factory lifter bores bushed is generally a $450-$600 machining operation, depending on the shop doing the work, and not every shop owns the proper BHJ fixture for bushing Small Block Chrysler lifter bores. However there is a second and less expensive way out of this predicament. You can install copper tubes in both the lifter oil galleys. Both passenger side AND drivers side. Then you can drill your .035" oil feed holes in the copper tube in each lifter bore, and the tube is what acts as your oil restrictor. Mopar Performance has sold the lifter bore tube and peen package for more than 20 years to block off all oil to the lifter bores. We are just putting a new twist on this old idea. With the tubes installed, your oil pressure will be back up to normal levels and your bearings will thank you for it.
As far as R, R1, R1A, R2, and R3 race blocks are concerned, the only differences that you need to be aware of, is the fact that the inner row of extra head bolts, and their bosses will need to be HEAVILY milled/ground off for link bar clearance on a solid roller lifter application. This is a time consuming and tedious task, that has to be done VERY carefully or you will break into the water jacket. Also, even the R3 block will still require you to either bush the lifter bores or tube the galleys to restrict the oil to the roller lifters, there is no way around this. The oil feed holes in the lifter bores are just too large out of the crate.
And there you have it, those are the basics of installing a W7/8/9 cylinder head on a 59 degree engine block. Now for the part most people don't think about/know about. MOST W7/8/9 heads have 15 degree valve angles. Stock LA heads utilize an 18 degree valve angle. This creates obvious problems when trying to just bolt a W7/8/9 on a standard 18 degree shortblock/piston combo. There is no easy way around this other than just having Custom 15 degree relief pistons made. Besides the fact, that W7/8/9s have wider valve spacing than most LA heads, and they usually utilize larger diameter valves as well. All of these factors necessitate that custom pistons be used under a W/7/8/9 head. The good news is, that with today's CNC technology, Custom pistons are not nearly as expensive as they were only 10 years ago. Today, most piston companies will do a fully custom piston combo for around $150-$200 extra. Well worth the cost, when you consider the added power gain of using a large "W" series cylinder head. For more info, and differences of W7/8/9 heads see the W7/8/9 section of the FAQs.
