360 Head and Cam choices for my Challenger

[cudazappa]

Well, Uncle Sam has bequeathed unto me some tax breaks, and since the $$$ has been slow lately this is likely the last I'll be spending on my car this season.  So I'm trying to get this right "for now" but leave an upgradable platform for future seasons.  (Please don't laugh, it sounded much cooler in my head before I typed it).

The car is my 71 Challenger.  Its pretty much a stock weight car.  904 trans with stock 318 converter, 3.23SG and 26" tall tires.  It is a driver, so I don't want to create something I couldn't drive 320 miles to Carlisle in relative comfort.

Right now this is what I have:

75 360
.030 over KB107s ~9.5" compression
Eddy Air Gap
Holley 670
70 340 manifolds and 2.5" dual exhaust.

I'm really torn between head selection as I'd like to get new assemblies, so I'm thinking the Indy AeroHeads, but after some searching, of course, there are some less than favorable reviews. If I AM going to get them, then I'll be getting their 915-587 kit with 2.02/1.60s (or put simply, these are the ones I'm seriously considering)

And of course, the heart of the combo, the camshaft. I'm thinking something along the lines of a Comp Cams xe268h

I'm sure I could probably gain some power band usage with a different converter, but there's another area I'm really a novice about.  I'm also concerned about the bang for the buck here, too.  Especially since the 904 will be replaced with a manual trans later in life.

I expect the engine to live in the 2000-6000 RPM window as it will see lots of driving duty to, during, and after autocrosses.  And the goal is to hit Lime Rock Park in June (maybe) and / or September (likely)

Any ideas, comments are appreciated.

[femtnmax]

CudaZ:  I've gone thru the same questions.  Your axle ratio and tire diameter is exactly the same as mine.  Soon as the snow melts I'll let you know how my car runs.

For cast iron exhaust manifolds should use a split pattern cam.  The XE268H sounds like a decent duration, though they say the 'rpm' comes in at 2500 rather than the 2000 your looking for.  BUT...when you go 4 speed that will drop your first gear ratio and help off-line performance.
One of the big complaints of the Comp cams is almost all are ground to fit chevy lifter diameters.  On the other hand Comps lobe/valve lift is not pushing the limits (old style somewhat conservative for longer valvetrain life).  Some say to reach for a cam matched to Mopar larger .904 lifter diameter.  Others say there is risk using the 904 lobes because these more aggressive cam lobes require the lifter bores be correctly located in the engine block, and factory tolerances were not all that precise. 
You could consider both Lunati and Bullet/Ultradyne...
I know from personal experience the Lunati cams lobes are ground smoother than the Comp lobes.  To me this is one sign of better quality.
For Lunati, their 60402 cam would work very well, has 112 LSA for smooth idle and broad torque curve.  Maybe slightly conservative, but should have excellent street manners and good valvetrain life (not wild valve lift) with 1.5 rocker arm ratio:
http://www.lunatipower.com/Product.aspx?id=1544&gid=287

For heads, as I bought parts for my 360 years ago I bought Edel RPM magnums to ge the increased rocker arm ratio and slightly better combustion chamber shape...they seem ok....but after cam break in I removed all the rocker arms to inspect the rocker/valve tip contact pattern.    Two cylinders (both intake and exhaust valves) have the contact pattern at one edge of the valve tip only, not laying across the width of the tip.  I thought maybe it was the rocker arm; but why BOTH int & exh valves on certain cylinders??  This has me questioning the angle the holes were drilled for the rocker arm studs.  I'm going to run it, have no choice, no mega $$ to do differently.
So maybe stay away from the magnum style heads for that reason, plus 1.5/1.6 rocker arm ratios are now more available for shaft mounted rocker arms (they are better than stud mount any way you look at it). 

Word has it TWO companies are working on performance cylinder heads for small  block mopars, supposed to be released end of this year or next.  I'd like to run what I have for a couple years then upgrade to something better if it is available.  IMO if AFR offered a SB mopar head I'd really take a look.

[boydsdodge]

Is that 360 together or are you listing the parts you have on the self?
If apart then I would get the block square, my 73 360 block was out from corner to corner and it will help get the compression equal.
I don't know how well this cam is going to work but when we (my engine builder and machinist) went through the needs of my car and engine we came up with a Roller Mutha Thumpr for the cam to use.
You might want to take a look at that one, But you will need the engine apart to do some block clearance grinding in the lifter valley for the lifters.
I loved TTI's in both my cars, I used to run the 69 340 manifolds in the swinger but when I went to the Edelbrock closed chamber heads I had to get a set of headers because you can't bolt iron exhaust to the Eddy's.
It was a cost at first but they are great and fit better then the Iron.
A set of Eddie closed chamber heads, TTI's, the Mutha Thumpr and your intake and you should be having a blast.
You will need adjustable rockers and new push rods. Don't forget to set the rocker geometry up on the valve ends. Also the Eddy heads will always need a valve job.
Did I just Blab on or what?

[cudazappa]

I'll say I'm spending some money on something I know I'll be reusing, the Milodon Oil Pan and windage tray and accessories.  Oh, and the intake, too.

The more and more I think about it, I think this is just going to be a mild 360 and make the next one a stroker.

I'm going the iron head route because its half the cost of the aluminum.  That allows me to afford the Milodon pan and also my Firm Feel steering box.  I know it hurts me right now, but there is some definite "needs" for the car.

Parts listed are my constraints.  If anybody wants to trade me straight up for a larger carb or good headers (my 340 manifolds were cheap because they've been noticeably repaired) I'm game.  No disrespect, because if I could afford the GREAT stuff, I wouldn't be asking for as much help.  But as I said, I've thought about it, and this engine looks to be a pretty mild mover, but definitely a step (or 3) above the 2bbl 318 now.

I looked at the Lunati cam.  It looks mild, but then I do realize I'm running a tight converter and "tall" gears.  It looks better than the Comp Cams alternatives (268H and 270H), even though it will cost more.  Thanks for turning me onto that one!

[Aussie Challenger]

Have a look at the RHS-X heads, out of the box they flow fairly well and much cheaper than eddies, they also benefit from the later combustion chambers.   

[cudazappa]

Have a look at the RHS-X heads, out of the box they flow fairly well and much cheaper than eddies, they also benefit from the later combustion chambers.   

I was really excited until I saw they were bare heads.   Having the valve work done (plus new valves) puts them close to the assembled Eddy Head cost.  *sigh*

[Aussie Challenger]

I have heard that the RHS-X still out perform the eddies out of the box and cheaper and the eddies usually need checking over before use to be on the safe side, poor quality control.   

[cudazappa]

I have heard that the RHS-X still out perform the eddies out of the box and cheaper and the eddies usually need checking over before use to be on the safe side, poor quality control.   

Well, after some pricing the finishing work, the RHS heads will be cheaper than the eddys.  Not by much though, so it still means they are out of the budget this year. 

[HP2]

I'd say to look at the Lunati Voodoo or Hughes cams as they will provide the most lift for a given duration of most of the off shelf cams out there. Also consider that you can look at a cam that peaks slightly less than your intended rpm range since it is advisable to shift 500 rpm higher than you cam's peak, so you may want to look at a 1500-5500 cam. This better keeps it in the rpm range as you run up/down the rpm range/shifting and the lower rpm range may help with autocross power.

For heads, that's a bit tougher. Mopar is no longer making iron small block heads. Obviosuly X and J heads are good choices but aren't always easy to find anymore. and can either be overworked or expensive. One of the best small block iron heads Mopar made more recently was the 576 castings in the 90s. These were a high swirl design like the 302 and 308 heads, without the associated cracking problems. They were made as a direct replacement for performance 360 and 340 heads, but never really caught on much. They could be origianlly found under any of these part numbers, P5249574, P4529269, and P5249768. I think before they disappeared they were also under P5007950. You might luck out and find some stashes of these somewhere. They were designed as a direct bolt on to LA engines and I think there were also comparable Magnum version that used the stud mount rockers. These heads would flow as well as out of the box as an untouched W2 or aluminum Edelbrocks and they were cheap, like $500 a pair. If you can find some of these, they will work much better for less work than porting up a set of regular 915 360 heads.

If you don't want to scrounge around for any of the above units, Hughes still offers their oval track sportsman iron heads, which are a pretty stealthy set up for flow without looking highly modified, with 2.02 intakes, $596 each complete. Another less expensive option is their LA Iron Rams, $412 each for 1.92 valves or $487 for the 2.02 valve version.

 

[cudazappa]

I'd say to look at the Lunati Voodoo or Hughes cams as they will provide the most lift for a given duration of most of the off shelf cams out there. Also consider that you can look at a cam that peaks slightly less than your intended rpm range since it is advisable to shift 500 rpm higher than you cam's peak, so you may want to look at a 1500-5500 cam. This better keeps it in the rpm range as you run up/down the rpm range/shifting and the lower rpm range may help with autocross power.

For heads, that's a bit tougher. Mopar is no longer making iron small block heads. Obviosuly X and J heads are good choices but aren't always easy to find anymore. and can either be overworked or expensive. One of the best small block iron heads Mopar made more recently was the 576 castings in the 90s. These were a high swirl design like the 302 and 308 heads, without the associated cracking problems. They were made as a direct replacement for performance 360 and 340 heads, but never really caught on much. They could be origianlly found under any of these part numbers, P5249574, P4529269, and P5249768. I think before they disappeared they were also under P5007950. You might luck out and find some stashes of these somewhere. They were designed as a direct bolt on to LA engines and I think there were also comparable Magnum version that used the stud mount rockers. These heads would flow as well as out of the box as an untouched W2 or aluminum Edelbrocks and they were cheap, like $500 a pair. If you can find some of these, they will work much better for less work than porting up a set of regular 915 360 heads.

If you don't want to scrounge around for any of the above units, Hughes still offers their oval track sportsman iron heads, which are a pretty stealthy set up for flow without looking highly modified, with 2.02 intakes, $596 each complete. Another less expensive option is their LA Iron Rams, $412 each for 1.92 valves or $487 for the 2.02 valve version.

Thanks for that input!  I found a core set of 308s at a reasonable price from another member for sale.  I'll go with the Hughes sportsman machining.  It'll be on the expensive side of what I had planned to spend (Around $900 by the time I'm finished, but I had planned on $700), but I think it'll be even better bang for the buck than aeroheads should the deal go through.  I'll give Hughes and Lunati calls when I know what I'm doing with heads about cams...

[cudazappa]

Well, looking at the Hughes site some more and what do I find, the RHS-X heads!!!

Linky

Guess I might go after these after all!  This is at my limit for spending (which means: will have to wait a couple weeks after I've got all the other expenditures underway) but is what I'm looking for.

Aussie Challenger, sorry for doubting you.  HP2, thanks again for reminding me about Hughes!

[Aussie Challenger]

cudazappa  no problems, I should have mentioned about Hughes in my original reply. I have been checking and think the RHS-X might be my answer so just sharing with a fellow CC.com member, thats what we are here for to help each other, everybodys build is different.       

[cudazappa]

No problem.

I've been doing the compression calculation thing with my new pistons and block at a nominal 9.6" deck height.  62cc heads are going to be TIGHT.  I'm looking at 10.3:1 compression!!!  ACK!!! with 67 cc heads they'd be 9.8:1 and I think I can get by with pump premium with that compression... *sigh*

[femtnmax]

Is the RHS 67cc combustion chamber the old open chamber style with NO quench built into the combustion chamber??   For street use I would really recommend having some amount of quench.
What is your piston top to engine block deck measurement?  What cam intake closing angle were you using?  A later intake closing will lower the dynamic compression ratio.  Speaking of that, what dynamic compression ratio did you end up with.
I use KB silvolites handy compression ratio calculator, if your not already doing so.
http://kb-silvolite.com/calc.php?action=comp

[cudazappa]

Is the RHS 67cc combustion chamber the old open chamber style with NO quench built into the combustion chamber??   For street use I would really recommend having some amount of quench.
What is your piston top to engine block deck measurement?  What cam intake closing angle were you using?  A later intake closing will lower the dynamic compression ratio.  Speaking of that, what dynamic compression ratio did you end up with.
I use KB silvolites handy compression ratio calculator, if your not already doing so.
http://kb-silvolite.com/calc.php?action=comp

thanks.  Well, I'm using the KB107s I bought from you!  The engine is FINALLY getting torn down next weekend.  I hope to get a deck height measurement then.  I did all the calculations using a deck height of 9.600"  I know a production engine WILL vary.  I can set up a tool to measure accurately.  I just can't machine an engine, ya know?  LOL  I already got the prices for the hot tanking, overbore, and new cam bearings.  What's decking now adding to the process?  LOL

I think the best thing to do is call and talk to Hughes.  At this point I might just get the sportsman valve job on the original 75 heads.  Maybe I'll get lucky and they'll be 587 castings...  But I think they're 974s.