Camshaft + converter for 318 w/302 heads

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75 Duster 360

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I am instling a 1985 model 318 with 302 cylinder heads into my 1972 Duster. The engine has low miles and the heads are in great condition, with new guides installed. I need to know what camshaft I need to run in it. I bracket race it only, so I need a camshaft for maximum rpm that these stock heads will work best with. Will milling the heads help any and will it affect my valve clearance with stock piztons? I have a 318 Streetmaster and a Performer intake to choose from. I am running 3.55 gears and my Duster weighs 2800 lbs. I have a new Mopar purple cam 280 .474". Will it work well with the 302 heads? What about a torque converter for this combo? Are the 302 heads worth porting? Thanks.
 
Well, if you "bracket race it only", then the next question is "are you looking to go fast?"
  1. yes, the .474/280 cam will work. I've used that cam in a few 318's (street cars)
  2. I would run a quality 9.5 converter, on the loose side (3800 stall)
  3. I would gear it so that you cross the line 200 rpm's before your shift point. That won't be 3.55's. It will be around 4.30's - 4.56's
  4. I would sell both your intakes, and buy a RPM air gap (edelbrock)
  5. Yes, you can port the 302 heads. I'd advise it or they will be the bottle neck of your combo.
What E.T. are you hoping to run? What class?
 
318willrun said:
Well, if you "bracket race it only", then the next question is "are you looking to go fast?"
  1. yes, the .474/280 cam will work. I've used that cam in a few 318's (street cars)
  2. I would run a quality 9.5 converter, on the loose side (3800 stall)
  3. I would gear it so that you cross the line 200 rpm's before your shift point. That won't be 3.55's. It will be around 4.30's - 4.56's
  4. I would sell both your intakes, and buy a RPM air gap (edelbrock)
  5. Yes, you can port the 302 heads. I'd advise it or they will be the bottle neck of your combo.
What E.T. are you hoping to run? What class?
Click to expand...
I race 1/8 mile bracket racing in the street and footbrake classes. I do not care what et it runs, just want it to have the correct power and torque curves. What cam will match these stock heads and a slightly raised compressio. ratio?
 
Would a smaller camshaft work better with these heads and intake manifolds that I already have? Maybe a 268/272 .450/.455 purple shaft? What is the max rpm that I can turn with these heads? What about advancing the cam timing 4 degrees?
 
75 Duster 360 said:
I race 1/8 mile bracket racing in the street and footbrake classes. I do not care what et it runs, just want it to have the correct power and torque curves. What cam will match these stock heads and a slightly raised compressio. ratio?
Click to expand...
sorry, I'm a little lost (doesn't take much.... LOL). If you don't care about the E.T. at all, why change the cam? Why port the heads? Why the 4bbl? What "correct" power and torque curves are you hoping to achieve? A lot of questions.... :realcrazy:

But if you want the 318 to have a little more life...... (is this the power/torque curves?)
.474/280 cam will work fine. A good converter as I mentioned in above post.

P.S. - If it's strictly 1/8 mile car, I would run 4.88 gears.
 
got a 86 318 roller cam motor outta a diplomat with 302s im planning the build on for a 73 duster, 1/8 mile heads up 7.49 class and lil street play!! interested in your results and what others advise...what kinda budget you working with? im try an see how quick i can go for how cheap! craigslist, swap meet,..dumpster diving,..any thing short of stealing or receiving stolen goods lol !!
 
I would take it out and flog it, and see what you have "As Is)
i understand that you don't want to install eng just to pull it halfway back out to change cam.
.474/280 would work good with 3500 stall.........but now you have to change the spring. 302 valve springs.....don't think will hold up.
so replace spring.....well might as well do some clean up of the ports. woop nicked the seat.....might as well do a valve job on it......Maybe a bigger valve........shave head for more compression.........shave a lot and bigger cam...........
see how that slope can get real slippery FAST!!!!:eek::D
I say throw it in stock with 2200-2500 stall. 2800 pound car....should run well!

If you go down that slippery slope.....well now you need lower gears, more stall, wider rims, Drag Slicks, drag slick tubes(have you priced just the drag slick tubs:() Now what about them stock leaf spring......old and tired.....need to clamp the front segment to get a good hook......or hay SS Spring.........spring relocation kit......Bigger slick.......Yup still sliding:poke::D
 
Something like the Comp 265 DEH would work well, IMO.
 
And as I have read, a roller cam is efficient but not too much advantage over a hydraulic flat tappet at this stage. I too have a roller 318 and 302's and wondering the best way to go.
 
For got it was a roller eng.....would re think the .474/280....have something built for the roller lifter you already have.
after you decide how far you're going to go down that slope.......
 
Cudafever said:
For got it was a roller eng.....would re think the .474/280....have something built for the roller lifter you already have.
after you decide how far you're going to go down that slope.......
Click to expand...
That darned slippery slope. I thought about that when I read the title of the thread. lol
 
For a money "challenged" individual like me.............It took almost 30 year to slide down most of that slope.........and what do i find at the bottom.........More slopes.......but now, they are all marked" Black Diamond" !!!!!!!!!:p
 
got a 86 318 roller cam motor with roller lifter came out a 86 diplomat with 85,000 miles on it....good running dont smoke or use oil...not tryin to be argumentative,..just stating,..will photo build dates tomorrow if i get time...posibile its been swaped i reckon...but doubt it..
 
I
dirty white boy said:
got a 86 318 roller cam motor with roller lifter came out a 86 diplomat with 85,000 miles on it....good running dont smoke or use oil...not tryin to be argumentative,..just stating,..will photo build dates tomorrow if i get time...posibile its been swaped i reckon...but doubt it..
Click to expand...

It will say what year block it is on the side of the block..
 
10/06/84 is the casting date on my block,..gonna dig up tittle when i get home,..thought it was a 86 brother said 85 it was his car...10/84 casting would be right for early 85 model year...
 
I have a roller block out of a 85 5th Ave. In storage so I can't read the numbers.
 
I run the 302s on my 273 with a bunch of duration, they work well, porting them is not always the best thing, they have good velocity stock.
 
I've got an opportunity on 302 heads they are bare. Getting checked at machine shop.
I have a 87 318 with U heads. As well I have a good running 67 273 with stock bottom end and 2bl pistons(non commando) 273 heads are stock with adjustable valve train.
Wondering which motor to use if heads check out ok.
Thanks
 
4spdragtop said:
I've got an opportunity on 302 heads they are bare. Getting checked at machine shop.
I have a 87 318 with U heads. As well I have a good running 67 273 with stock bottom end and 2bl pistons(non commando) 273 heads are stock with adjustable valve train.
Wondering which motor to use if heads check out ok.
Thanks
Click to expand...
put the 302s on 318 with 273 crank an rockers, make a tuff lil motor!
 
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