Moparts Tech Archive

Small Block

SB Head Summary

I'll start it off with a topic that never seems to end, at least for me. CYLINDER HEADS. In the past year or so I have gained a large amount of knowledge about SB Mopar racing cylinder heads and continue to learn more and more daily. Last year at this time I had a set of POS 2.02" J heads and had run 12.97 @ 109 MPH. I wanted to step up. I knew the key to making more power was all in the heads. So I started doing some investigating.... there were several options out there in my budget. Edelbrock, Indybrock, used W-5's, or W-2's. I knew I wanted something trick and aftermarket. No more factory cast iron. I talked to board members, went back and read alot of old magazine articles etc etc. Tried to gain as much info as possible before making my decision. At the time everyone was all hyped up about the new INDYBROCKS. Supposedly the greatest new head out there, the price was good, the flow was awesome, everybody and their brother was buying them. at the time they were all the rage on moparts. Anyhow, I had a shot at a set of Ported W-5's that were off a low 9 sec tube chassis car. I talked to some people, they said W-5's had problems and that I should look before I leap. Also I felt that the flow #'s from them were more than my 360 could handle. Kill all bottom end power etc etc. (I was a misguided sole LOL) So I chose not to buy them. THEN came a defining moment in my life. I was up at neighbors house and they had new issue of Mopar Muscle magazine there, that I had never read before (OK I admit I am not a subscriber I read their copy to save $) Anyhow, THERE IT WAS...... "Porting The magnificent W-2" By Steve Dulcich. Step by step, detailed instructions on how to home port W-2 heads along with flow #'s from each step of the way. That was all it took. Soon after I ordered up one single W-2 Head form Mancini and went at it with the grinder. Ordered some valves and sent it up to Dwayne to see if I was a hero or a zero. Flow #'s came back and I had over 300 cfm. I was on cloud nine that night. This was the first flow test I ever had done of a cylinder that I had ported. My #'s were real close to the final #'s achived by Steve D. I was pleased. Bought the second head and ported it to match. Got myself some W-2 rockers, a used W-2 Strip Dominator, and some 2" Hooker headers. Threw this all on a 12.5:1 360 Shortblock with stock rods, stock crank and KB pistons. Fired it up, drove it around for a while, destroyed some trannies and had some fun. I thought the motor was nasty. Was kind of preparing it for it's first trip to the strip when I "accidentally" punctured the POS Moroso 8qt. oil pan. So I ordered a new 7 Qt. Milodon. Woudl'nt fit. Coudl'nt get the damn thing on the car with the engine already in. So engine came out, while it was out I just wanted to tear it down and see that the shortblock was OK. Unfortunately the high HP and RPM had taken it's toll. # 2 + 4 Main caps had BAD walk and the bearings had lost their crush. BADLY, as in I don't know how they were not spinning. The cylinder walls were showing signs of wear, the rings were gapped for heavy nitrous loads, etc etc. "mrw5" had gotten it in my head during Chryslers @ Carlisle where I first met him BTW, that my stock rods were not going to live under W-2 heads and that they were time bombs. Well MY rod's and bearings looked OK, but at about this time we were tearing down a buddies 340 that also had stock rods, and they all came out ovaled badly, no crush and also on verge of spinning. That pretty much solidified that I was not putting stock rods back in my motor. Sooo I am left with H beam rods, well if I'm putting H beams in I have to get it balanced. Well If I'm getting it balanced I'm not putting a 360 crank back in. So 4" crank it is. Stroker was done in 2 weeks and on Aug 24 we finally made it to the track to see how the W-2's would perform. Keep in mind the quickest the car hhad ever gone prior to this was 12.97 @ 109, with a 1.92 60' First pass off the trailer it went 12.20 @ 89 MPH. Left good, When I hit high gear no fuel. went back to pits, everyone says it pulled the left front tire off the ground..... I'm like well that's a good sign. But no fuel kind of sucks. mrw5 had already tried to warn me, the mechanical pump was'nt going to cut it. Luckliy I had second line plumbed for Nitrous use. It was a 3/8 hard line with Holley Blue Pump and reg. We hooked it to 870 Race Demon and away we go........ result? 11.2 @ 119 mph......... Oh so good. Messed around some but never really got better than 11.18 @ 121. Then got ahold of 451 Jim's 950 Hp carb. Bolted it on and went 11.02 @ 123. Oh yeah....... next pass paydirt 10.91 @ 123. Messed around and got a 10.88 @ 124.10 In less than 10 passes I had gone from an almost 13 sec car to a 10 second car. Took the car back month later with Dominator and went the 10.75 @ 125.24 in a 15 mph head wind. My 6.80 in the 1/8th converts to 10.67 by NHRA correction factor. I would have loved to know what it would have ran with no wind. It had more in it, as I had 14 passes on the motor total and it basically got quicker every pass toward the end. The limiting factor was # of passes, me shifting too early, and the Camshaft. Later Dyno test showed the motor was still pulling at 7000..... ANYHOW........ There was a message to this story, and it was that "It's all in the heads"

What Started off with me picking up a copy of Mopar Muscle magazine ended in 9 months later transforming a 12.97 car in to a 10.75 car. I think it's a pretty neat story. ANYHOW now taht we know, how important a role good cylinder head sare in an engines performance, Let's discuss aftermarket heads shall we?

First I'll make some generalizations here. EVERY FLOWBENCH IS DIFFERENT. HOWEVER: Most Shops use a SF-600 and the Following #'s are GENERALIZATIONS of Flow characteristics as I have seen them in the various SB Chrylser heads. They may not be exact #'s from a certain bench.

Stock 273/318: These are a small port 1.75"/1.50" valve head. Very poor flow characteristics for racing purposes. ~135 cmf intake flow. Can be had in both open and closed chamber versions. Many later versions inculded swirl port etc. IMO Any head with a small port like this is not a great candidate for racing use. TOO Many people get caught up in this 308/302 "magic Swirl port" head game. Fact is, they are OVERRATED. If you want to make HP don't waste your time with 318 heads I don't care if they are "swirl port" heads or not. JUNK unless you have forced induction.

Stock 340/360 "J" head. I'm talking 596/915/587 castings etc. 1.88/1.60 valves. Larger port desing than 318/273 heads. All open chmabers, USUALLY in the 70-72 cc range. Flow #'s are around ~185 cfm stock. Best upgrade, Have machine shop cut for 2.02" Intake valves and do a 3 angle Valve job with 70 degree bowl cut. This alone without tocuching the rest of the ports, should bring a "J" head into X head territory, and beyond. "Fast One" is our resident Factory Iron head expert, and he has gotten over 280 cfm out of a fully ported Iron head. IMO this is about as far as they will go. Other drawbacks inlcude weight (iron), large open chambers, a poor flowing exhaust port, and lack of flow above .600" The exhaust port is probably the Iron head greatest weakness. You can make the intake port flow ungodly #'s if you want, but if you can't expell all the burnt Hydrocarbons, the guy in the other lane is gonna WIN. This is why guys resort to WELDING up the exhaust on factory iron heads for better exhaust flow. ALOT of work. For all out racing unless a factory iron head is required by rules, this is not the best way to go.

Stock "X" head: See above. Out of Box, they'll go in the ~215 cfm range, which is about what a J head will do with a 2.02" Bowl cut.

"T/A" Head: See above. These require offset T/A Intake rockers. No great advantage. Leave these for the restoration crowd.

Edelbrock: Two versions, open chamber and closed chamber. Aluminum, very light weight. 2.02"/1.60" Stainless valves. As cast they will flow ~240/180 cfm. Potential exists for 285-290 cfm intake flow with alot of port work. (Read $$$) They accept stock intake manifolds, stock style rocker gear, and Stock header bolt pattern. The low and midlift flow #'s of a fully ported Edelbrock will flow right with a W-2 until the big lifts, where the W-2 pulls away. .600" is where the W-2 Shines and the E head dies. It is all about the Bowl size/shape and short turn. Nothing the E head can do about it, it was not cast as a race head, therefore it does'nt have the greatest short turn in the world. Similar porblem with the factory Iron heads, they die at .600" lift and nothing you can do about it. For the $ the E head is a great choice.

INDYBROCKS: Indy Cylinder heads modified version of the Edelbrock head. Relocated pushrod holes. Requires offset Indy Rockers. Uses stock intake and headers. The initial enthusiasm has worn off, when guys started putting these on flowbenches and found they were no better than fully ported regular E heads at a higher cost

Brodix B1-BA: Cast Aluminum. 59*. Closed chambers. Uses stock intake, Stock rockers, stock headers. Fully ported will flow ~300/220 cfm. More $ than E heads or W-2. Not very popular most likely due to cost. Overall a good head that is better than an Edelbrock, but no greater than W-2.

Brodix B1-BA-MC: Cast Aluminum. 59* Closed chambers. The MC stands for Moved centerline, and is designed for a bore larger than 4.10" Offset race rockers required.

Mopar Commando: Cast Aluminum. 2 versions small port, and a large port. Come bare, with roughed in 2.02"/1.60" seats. Cast in rocker stands, uses stock rockers, stock intake, and stock headers. Very little actual use or flow/dyno testing. "Carl" is teh only person I have even heard of using these, however he is achieving excellent results. More $ than E heads, on par with B1-BA's price wise. VERY underated head IMO

INDY 360-1: Rectangular Port, closed Chamber. Aluminum copy of Batten's old W-2, only with revised chambers and rectangle ports. Uses INDY Rockers, Stock exhaust, and a W-2 style intake. INDY Inflates the Flow #'s on these heads, and they come cast with a poor valve Job. Fairly expensive as well. Most sold in "kit" from. Actual Flow #'s from a set fo Fully ported (by INDY) heads on a SF-600 showed 321 cfm @ .800"!!!! However, cfm @ .600" was only 299 and at .500" it was 269 Making it worse than a fully ported W-2 at the lower lifts.

INDY 360-2: Cast Aluminum, Oval Port version of the 360-1. See above, plus the Oval port version is said to flow less than the rectangle port version.

Mopar W-2: Cast Iron, many different Combustion Chamber versions, open, closed, 65cc, 55 cc etc etc. 48* versions, 59* versions. ALOT of options. Cast in rocker stands (econo version) Race rocker stands (all but econo) Standard length valves, or Long race valves. All come with roughed in 2.02"/1.60" seats. Bare castings. Out of the box flow 268/175 cfm. Require a W-2 bolt pattern intake, W-2 Offset intake rocker arms, and a W-2 style header flange/adapeter plate. With full port work, flow in excess of 315/220 cfm. They have an excellnt short turn out of the box, and will flow all the way to .700" with proper short turn blending. The Econo versions are economically priced in either $320 each (std length) or $350 each (long valves) Also a very $ friendly head IF you don't have good rockers/intake to begin with. If you are not palnning on running over .600" lift cam, the E head will flow right with a W-2...... The W-2 exhaust port being slightly better IMO.

Mopar W-5: Cast Aluminum, bare castings, no longer produced. 59cc closed heart shaped combustion chambers. Roughed in 2.02"/1.60" seats. Have BAD reputation for casting and valve seat problems. Some true, most misconceptions. Several different castings over the years. Out of the box with a 3 angle VJ will go: ~280/160(?) The exhaust is terrible as cast. Potential exists for 340/245 cfm with FULL port and large valves. The Secret to the W-5 is it's low and mid lift Flow #'s. BEST 59 degree head out there. Requires Race W-2/W-5 offset rocker setup, W-2/W-5 Intake, and W-5 headers.

Mopar W-7: Cast Aluminum, bare castings no longer produced. Closed Chambers. MANY different versions avail over the years, some 59* heads some 48* heads. Requires a "Lazy W" Rocker arm setup. W-7 intake and W-7 headers. Few people run the W-5, even fewer run W-7's.....

Mopar W-8: Now were are into exotic stuff. 48 Degree R-3 Race block required. W-8 Rockers (JESEL, T&D ect.), W-8 Intake, W-8 Valve coers, and W-8 headers required. Bring your check book. Most get CNC ported, and will flow in the 365 CFM range.

Mopar W-9: Again 48* R-3 required, W-9 Intake, W-9 Rockers, W-9 headers. Do use standard valve cover unlike W-8. Again CNC porting will be in the 365+ cfm range. valve size on a head like a W-8 or W-9 will be in the 2.18" range and you will be running a BIG bore motor to deshroud the valves.

Mopar P-7: Cast Aluminum. NASCAR Winston Cup head. Requires R-5 Race block. P-7 rockers, P-7 intake, P-7 headers, P-7 valve covers.

Mopar P-5: Now we have reached the Pinnacle of all SB Chrysler heads. The one we all wish we had the $ to afford. Designed for NHRA Pro-Stock Truck applications. Cast Aluminum, Hemi Combustion Chambers. R-4 race blcok or Aluminum Block required. P-5 valve covers, P-5 rockers, P-5 headers, P-5 sheetmetal intake all required. Better bring your Visa, and hope you have a DAMN high credit limit. LOL

Hopefully I hav'nt left out any of the major heads.... This is just kind of a brief summary of the various heads avail. for SB Chryslers today. To summarize, IMO W-2 is best bang for the buck, but it might be overtaken by the large port Commando's If I can ever get my hands on a set. Edelbrock is bettern than Factory Iron any day, but not as good as Commando's. W-5 is best 59 degree race head, with teh B1-MC on it's caot tails and INDY 360-1 lagging behind. And the only REAL serious race heads are all produced by MP in the form of W-8/W-9 and P-7. The P-5 is soo exotic I don't even think they are avail to the general public. For the guys who are thinking about building a 10 sec or quicker SB Chrysler, this should give you some idea of the direction to turn. And Lastly if you actually sat at your computer and read this entire novel, I commend you. You just lost 10 minutes of your life you will never gain back

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