I currently have comp magnum .470 .470 cam. I was told this cam would seem small in a stroker 318 when stroked with a 4 inch crank. I like the sound of this cam which is why I liked it in my 318 mild build. I'm told cubic inches swallows up duration and turning the 318 into a stroker it would'nt sound the same. I would like my motor to sound like it's got a cam in it when it's assembled, so I would like a cam that has a choppy sound or sounds nice and loppy. The engine still has stock valve train, so I'm sure I can't go extreme and It is a street car. The springs are comp cam springs that cam with the magnum .470 cam I am not sure how much lift they are rated at, I think .500 I may be wrong. Anyway this is what I have to work with. 3.55 gears,hughes 2500 stall,headers,650edlebrock,performer intake I am going to change to air gap,mopar performance ignition,318 heads pocket ported and blended gasket matched with 1.88 intake 1.60 exhaust,mopar performance thin head gasket,the block is bored .40 over, and a 4 inch stroker kit, with 23cc forged dish pistons. I have looked at the xe275hl comp cam but I think I would need adjustable valve train and machine work for retainers. I'm not sure though. I know it's a street car and maybe xe275 may be to big anyway I just want somthing that sounds awesome. Any help would be great.
If you have the springs that Comp recommends for the 470/470 cam, they would be the Comp 901-16 springs and Comp does not recommend anything over .480" lift on those springs. If you set the 901 springs at the recommended intalled height of 1.65" they will coil bind at about .550" lift. You can run the XE275HL camshaft with the stock rocker arms if you use the 822-16 lifters. If you go to the high performance 867-16 lifters, then you have to use adjustable valve train because those lifters use only .002-.004" preload. With the XE275HL you must machine the cylinder heads to use the recommended 995-16 valve springs because they are dual springs and won't clear the valve guides as machined on the stock head.Generally, with the pocket ported 318 heads and the 1.88/1.60 valves, the heads will stall around .450" lift, and a 392 ci small block is going to want more flow than your 318 heads will provide. Can you still use the 318 heads on your stroker? Absolutely. They will work OK on the street but will limit the horsepower potential of your stroker. Comp Cams has the Thumpr camshaft line and Hughes Engines has their Whiplash cams just for the sound you are after along with good street manners. Perhaps your best bet would be to contact them and get their recommendations.
Thanks for the info. I will get better heads one day, but it's still just a street car. I would like to take it to bandameer one day just to see what it will do. I will call Hughes or Comp to get there input. Thanks again.
I'm assuming it's a LA series 318ci. The almost 6000ft elevation at Bandamere track is a big HP killer for naturally aspirated engines, regardless of cubic inches or cylinder heads. You could get a decent set of LA 360ci iron heads that will flow a lot better with you 392ci stroker than the stock style small valved LA 318ci head, The Magnum 5.2/5.9ltr heads flow much better, but you need to do some changes to your, push rods, valve train & intake to use them... You can see some threads on the subject use the -Search- in "blue" in the grey section near the top of the page in between -Active Posts- & -My Threads- .... Good luck. Budnicks
"Fill Your Library Before You Fill Your Garage" Good Luck "Budnicks"
Head wise, I would go with a set of RHS LAX heads. They flow better than any factory head and are very inexpensive. They would work excellent out of the box on your stroker or you could have them modified a bit. Indy Cylinder offers some nice packages on those heads. They will set them up with the right springs for the cam you have.Cam wise, Hughes Engines offers some nice short duration, high lift cams that would work well with your stroker.
What ever you do, get rid of the 318 heads. At 390+ cubes the 318 heads are useless. Cam? With the rest of the set up you have the 241 @ .050 cam will work with the 484 lift. This will work with the springs you have and should be about 10 degrees more duration than your current 474 cam. This would be the bare minimum cam you can get away with with a 390 stroker. Good Luck..
Go roller...I had a roller 340 with some x-heads...It was like a 534/536 roller cam...then call Rhoads lifters and beg them to make a retro roller lifter for you...I already did for my 440...that way you can have huge duration with great vacuumhttp://www.rhoadslifters.com/
1977 Dodge Aspen R/T318 4 speed overdrive 21,000 original miles
I originally bought the heads for just a piston upgrade in a 318 and a cam for cruising around. I did'nt figure on getting a stroker kit this soon, but beings how I did I am going to have to make the heads work for a little while. The cam I would like to change for sure. Thanks.