Opinions on this setup ? ?

[mferraro76]

Currently in the works: 318, bored .030 over, stock cast crank, stock rods, forged pistons. I am looking for a weekend driver with some snot. I was thinking about supercharging but the CR is prob gonna be too high (9.5:1 est) and i'll likely do a separate build specifically for that later.

i am thinking about adding the RHS heads and the RPM air gap intake. currently i have a 625 cfm carter, i could go bigger if needed. i can't decide if i should keep my current cam (purple shaft 284/284 dur, 484/484 lift, 108 centerline, 241/241 @ .050) or step down to something in the 1500-6000 range.

So, am i tapping into the capabilities of this block or am i using the wrong combinations?

also, would there be benefit to a better oil pan, windage tray, or other goodies while this thing is apart?

(other misc info: 3.23 rear, 68 sattelite, will prob use tti headers, already have mopar electronic ignition and would like to reuse, have beefed up 727)

 

[Meep-Meep]

With 9.5:1 CR I'd ditch the .484" cam. Personally I'd consider the factory 1973 340 cam or perhaps something with a slightly tighter lobe sep to increase max torque. For good street drivability I'd stick to a cam with about 112 deg of lobe separation and get the cranking pressure as high as possible without detonation, but the ideal CR and cyl pressures for good results will vary. Seems 9.5:1 and 170-180 PSI with iron heads, or a half point more CR when using aluminum heads is a good start. The 3.23 gear alone is reason enough for me to NOT use the .484" cam. 625 CFM will be plenty.

If you plan to spin it to 6000 RPM doing some basic oiling mods will be a good idea. However, the cam you will end up with may not allow for much time or produce much power at those engine speeds. Freeing up the suction side of the oil pump (i.e. larger pickup tube) and a bit more oil pressure is never a bad thing though. 50 PSI for 5000 RPM and 10 PSI per 1000 RPM after that. I like to put a windage tray in everything I build and that frees up some HP too. Running a low drag water pump and a clutch fan is good for a few extra HP too.

 

[Coronet 500]

Just a couple things, think about the 360 rods as the 318's are quite puny and don't use 2.02" valves with the small bore, 1.92" is the biggest I would go.

Agree about the 484/284 cam with that gear but I might go a little bigger than the 340 cam. That manifold is alot for a 318, turbo and supercharged engines prefer single plane manifolds if you go that way.

 

[mferraro76]

the rhs heads have the 1.92 intake valve, so no problems there. might talk to the machine shop and see what porting options exist for my current heads, and maybe save a couple $$ over new rhs heads. i'm not going to race, i don't plan on spending much time above 6000prm so i'll prob go with a cam in the 1500-6000, idle-5500 range or around that.

i saw an article where they supercharged the 318 and used a 223/232 at .050 cam with 556/589 lift, 113 deg separation. it had good numbers when dynoed with the s/c disconnected, so i thought i might go this route and then if i go s/c later, i already have the cam. only issue is heads and valvetrain accomodating that much lift.

i've heard the single plane/dual plane debate with forced induction, and really, if i do that, it might be a couple years before i get there, so i can always keep my eyes out for a different intake along the way. i doubt i will use this block for anything crazy, so new rods is something i will save for later, too.

advice taken with the windage tray and oiling psi, thats the help i need.

 

[IQ52]

Just a couple things, think about the 360 rods as the 318's are quite puny and don't use 2.02" valves with the small bore, 1.92" is the biggest I would go.

Agree about the 484/284 cam with that gear but I might go a little bigger than the 340 cam. That manifold is alot for a 318, turbo and supercharged engines prefer single plane manifolds if you go that way.

Why would you not use anything bigger than a 1.92" intake valve in a 318?

 

[mferraro76]

Why would you not use anything bigger than a 1.92" intake valve in a 318?

supposedly, the rhs heads with the 1.92 intake flow just as good as the edelbrok with the 2.02 intake...plus/minus a couple cfm.

from what i have read, there are conflicting views on whether the 318 bore can fit the valves. also, i'm sure there may be some engineers who can get into fluid dynamics and explain why a smaller valve may benefit certain engines.

 

[67 B-body]

supposedly, the rhs heads with the 1.92 intake flow just as good as the edelbrok with the 2.02 intake...plus/minus a couple cfm.

from what i have read, there are conflicting views on whether the 318 bore can fit the valves. also, i'm sure there may be some engineers who can get into fluid dynamics and explain why a smaller valve may benefit certain engines.

I can tell you without getting into alot of detail. Some engines need larger runners, some require smaller runners. This goes hand in hand with valve size. If you have an engine running at say 5500 rpm, and not built with high comp and high cyl pressures, you might not want to have LARGE flowing runners due to the loss of velocity. Larger displacement high comp, high cyl pressure can bennefit from larger runners / ports because they can effectively flow and maintain the needed velocity. Think about how an engine runs when you over carb it. Large CFM on a smaller CID engine will just fall on its face if you just smash the throttle,,, Why? not enough air moving "volume" to support the opening provided. The same applies to ports and valves.

 

[mferraro76]

ended up going with a lunati 262/268, rpm air gap, 2000 stall converter. not sure if i should pop on some new heads or grind the heck out of the old ones, but the stock have the tiny valves and softer seats - so i should do something.

thought about magnum heads - but $ for $, i thought it might just be better to go for the RHS x with SS valves, already assembled, no worries about changing pushrods, intake/header differences, machining...nice easy bolt on.

 

[Patrick]

Currently in the works: 318, bored .030 over, stock cast crank, stock rods, forged pistons. I am looking for a weekend driver with some snot. I was thinking about supercharging but the CR is prob gonna be too high (9.5:1 est) and i'll likely do a separate build specifically for that later.

i am thinking about adding the RHS heads and the RPM air gap intake. currently i have a 625 cfm carter, i could go bigger if needed. i can't decide if i should keep my current cam (purple shaft 284/284 dur, 484/484 lift, 108 centerline, 241/241 @ .050) or step down to something in the 1500-6000 range.

So, am i tapping into the capabilities of this block or am i using the wrong combinations?

also, would there be benefit to a better oil pan, windage tray, or other goodies while this thing is apart?

(other misc info: 3.23 rear, 68 sattelite, will prob use tti headers, already have mopar electronic ignition and would like to reuse, have beefed up 727)

Stroke it to a 391 and with the RHS heads, your cam a 2500 stall converter You'll a nice 400 horse thats easy to live with.