road race engine...

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Just build a cast crank 318, 6,000 rpm ain't **** for any amount of frequency.

Forged pistons are lighter than stock, use a set floating pin /bushed 340 rods for insurance. The cast crank isnt a problem, the skinny rods might be, hence the 340 rod insurance ...its the main caps imo, they are the weakest of all, still designed around a 273's limited power potential and little pistons. The front main caps have been known to crack under very extreme circumstances back when.. That may never be an issue these days, tighter balance, lighter parts...dampeners... maybe a hair better than a late 70's race version.

Just make sure all oil passages are sized correctly and not under, like many, and go full groove "hard bearings", as my friend always said..lol no soft dirt forgiving ****.
 
what rods are you thinking of NM that are lighter than the 360 rods
lots of difference in pins also
 
So the build plan is looking like: magnum block with all the oiling mods.High volume pump with a bigger pickup tube.Stock crank.Baffled/gated oil pan.scat I beam rods floating pin, KB-167 pistons,zero deck block,EQ cast iron magnum heads with as big of an intake valve that will fit-stock exhaust valve size,214/218-110 LSA cam,Hughes shaft mounted rockers,FI M1 intake,all topped off with a 14x5 airfilter to keep dust out.Then a set of longtube headers in either 1 5/8 or 1 3/4.
 
So the build plan is looking like: magnum block with all the oiling mods.High volume pump with a bigger pickup tube.Stock crank.Baffled/gated oil pan.scat I beam rods floating pin, KB-167 pistons,zero deck block,EQ cast iron magnum heads with as big of an intake valve that will fit-stock exhaust valve size,214/218-110 LSA cam,Hughes shaft mounted rockers,FI M1 intake,all topped off with a 14x5 airfilter to keep dust out.Then a set of longtube headers in either 1 5/8 or 1 3/4.
Pick an intake valve that isn't gonna be shrouded to death. What cam??
 
Header wise use ether the TTI stepped header or straight 1-3/4.
FWIW! Your baffled/gated oil pan should be a Milodon road race pan.
Also include a really good timing chain! Hughes Engines has a nice unit.
A 2.02 intake is mucho enough for the 318.
Look into a crank scraper & windage tray.
 
see what rocker arm specialists thinks about the shaft mount rockers, they will give you the straight shot check who mfg is, Hughes does not make
I'd also check with B3racingengines- he will also give you the straight shot and if the geometry is correct with those shaft rockers
On the Hughes cam, look up the cam in theHoward catalog AND cross reference the lift and duration with the Howard lobe list- see what you are getting
https://www.howardscams.com/sites/default/files/lobe list email 1-20-2014.pdf around page 8
If I was getting an endurance/ road race cam Mike Jones would be my go to with his Indy cam and GM R&D dollars into that application
The resulting inverse radius profiles are superior to Everyone elses
really easy on the valvetrain and no bounce on the close and they rev well
Also many threads about problem with HR so check it out
I see that Howards has a timing chain with an Iwiss chain (but maybe only for chevy) that's the chain you want if you go chain- check Manley and other quality vendors but I'm with YR on a gear drive
 
What we used to do in jr fuel
junkyard 354 Hemi, our cam and heads and 6 3 bolt Strombergs
tip the can, skinny tires lots of smoke- no slipper clutch sometimes shift trans
was FUN back in the day
Then our driver wanted to go after Garlits, put on the blower, top fuel
short chassis- got himself killed
Not fun
what's worse is I'm not coming up with his name and I feel bad all overagain like it was yesterday
gotta go paint the house
 
What do you think of this cam from Lunati
"Retro-Fit Hydraulic Roller. Good high performance street cam with slight lope. Works with all power acces- sories. Fair idle.; Advertised Duration (Int/Exh): 276/284; Duration @ .050 (Int/Exh): 210/218; Gross Valve Lift (Int/Exh): .492/.492; LSA/ICL: 112/106; Valve Lash (Int/Exh): Hyd/Hyd; RPM Range: 1200-5200; Includes: Cam Only"

I'm thinking it should give a broad power band, and on a 318 I'm thinking it would work up until about 6000RPM.
 
Just spoke to lunati and they recommended this cam, its one of the larger roller cams they make "Retro-Fit Hydraulic Roller. High performance street cam. Likes up- graded intake, carb and exhaust. Needs 2800 RPM stall converter in most cases. Requires 9.5:1 compression. ;Advertised Duration (Int/Exh): 282/290 ;Duration @ .050 (Int/Exh): 231/239 ;Gross Valve Lift (Int/Exh): .535/.550 ;LSA/ICL: 110/106 ;Valve Lash (Int/Exh): Hyd/Hyd ;RPM Range: 2200-6200"
 
What do you think of this cam from Lunati
"Retro-Fit Hydraulic Roller. Good high performance street cam with slight lope. Works with all power acces- sories. Fair idle.; Advertised Duration (Int/Exh): 276/284; Duration @ .050 (Int/Exh): 210/218; Gross Valve Lift (Int/Exh): .492/.492; LSA/ICL: 112/106; Valve Lash (Int/Exh): Hyd/Hyd; RPM Range: 1200-5200; Includes: Cam Only"

I'm thinking it should give a broad power band, and on a 318 I'm thinking it would work up until about 6000RPM.
I stuck that cam in a magnum 360 early this year... just got to get some time to get it on the Dyno, maybe over Christmas if It works out.

32BA4157-E966-49EB-B330-7DC2ED1C873E.jpeg
 
what rods are you thinking of NM that are lighter than the 360 rods
lots of difference in pins also
I was thinking SCAT I beams..... they run around 155 grams lighter each than stock rods. I'd not put TONS of power through them but the rally roads limit the torque you get on the drivetrain.
 
So the build plan is looking like: magnum block with all the oiling mods.High volume pump with a bigger pickup tube.Stock crank.Baffled/gated oil pan.scat I beam rods floating pin, KB-167 pistons,zero deck block,EQ cast iron magnum heads with as big of an intake valve that will fit-stock exhaust valve size,214/218-110 LSA cam,Hughes shaft mounted rockers,FI M1 intake,all topped off with a 14x5 airfilter to keep dust out.Then a set of longtube headers in either 1 5/8 or 1 3/4.
I'd really like to see you reconsider the heads and go with AL. Losing 80 pounds off of the front end is going to be a BIG deal for a rally car.

Trust me..... you're traction limited all over.. including side bite for cornering. So it will make the shocks/struts that much better to be able control the tire contact on the road. And with the engine in the stock position, and a RWD rally car's extreme 'tail-out' attitude, quick and large amounts of car rotation in twisty left-right-left linked corners (like on the Idaho NF roads) is going to be important, and if you add weight hanging out in front of the front wheels or behind the rear wheels, it is a killer for quick car rotation. My Starion was a nice short wheel base, but the gas tank hung way back behind the rear wheel, and overall the car was a tank. and I knew is was there when I tired to run fast through twisty corners. My 1.6L Arrow and 1.9L Opels were quicker everytime through the tight stuff than the turbo 2.6L Starion, which had a 275 to 125 HP advantage over the smaller cars!

Get that weight off!
 
Did you find a link in the lunati catalog for springs?
how much does that cam take?
IMHO you are going to end up with a custom grind
get a second opinion from Dart19666 and Mike Jones
either can give you more mid range and the same or better top end than Comp or Lunati
good to know autocross looking fwd to your results
 
The weight savings on the aluminum head would be nice, but all of the aluminum magnum heads are fecking chevy bullshit adapted to fit a mopar.They all have 2.02 and 1.60 valves and you have to run 3/8" chevy 1.6 rocker arms.In stock form the magnums have 1.92 and 1.625 and the combustion chamber and intake runner cc's are close enough that the magnums could easily be massaged to be better than the aluminum offerings.Doesnt seem worth it to loose exhaust flow, and have to run crappy chevy valve train when the damned heads cost $1000 a piece. There's plenty I can still do to get the weight of the front end.
 
do the magnums you are talking about have 8mm or 5/16 stems
if so they are not using sbc valves
we used to use +100 sbc valves in LA motors with the conversion guides or 5/16
some backset the studs in magnums and run I think BBC rockers or maybe ford
this also gives you room for larger pushrods
problem with the stock magnums is they crack- mine did
The aftermarket al heads should have better ports otb than the stock magnums
and 1.6 exhaust is plenty for a road race motor
you need to keep your velocities up - you are not building a drag race motor
keep at it
who has the list of roller rocker arm lengths
btw the stock magnum rockers work fine, some say to quite high lifts
 
like I said the stock magnum head has a bigger exhaust valve than the aluminum heads.Thats BS.Especially when our engines favor the exhaust stroke because of the long rod/short stroke.
 
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