360 cam selection

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71abodys

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hey guys sorry to ask the same ol question which I'm sure has been asked 100 times but here ya go! I have a 71 Demon with a slant 6 that is dyeing a slow death. I just picked up a complete 360 for almost nothing (trade). The bottom end consists of .030 speed pro 405p dished pistons. the heads are stock 596's that have been gasket matched and a-little clean up work. topped with an RPM dual plane intake and 650 eddy carb. Full length headers with stock converter with a 904. REar is an 8 1/4 with 3.23's The cam is unknown but appears to be stock in the .420 range from the dial indicator. I would assume with the pistons down in the hole and dished pistons and stock heads 8:1 compression would be alot. I would not be opposed to cut the heads to get the cc's on the heads down. I want a cam that sounds better then it performs. I know with this combo I'm not going to get both worlds but the car isnt going to raced just cruised around. What are your thoughts?? how about the small thumr cam? THANKS!!!

VALVE LIFT @ 1.6:1

LOBE SEP. ANGLE

ADV.

@ .050”

IN. EX. IN. EX. IN. EX. IN. EX.
HYDRAULIC FLAT TAPPET: High performance street, stock converter ok, best with 2000+ converter and gears. Choppy/thumping idle.

Hyd

Hyd

2000-5800

20-600-4

279TH7

279

296

227

241

.486

.473

107°
 
Until the low static compression is verified and addressed if need be, a larger cam would make it miserable and a complete dog to drive. You would also need to address the converter.
 
71abodys said:
I want a cam that sounds better then it performs.
Click to expand...

If this is the case, that thumper is probably a good bet.

If you want to keep some good low end power, there are other's available.....And skep's grind is a pretty good one for your combo...
 
Or a Hughes whiplash cam they are designed for low cr
 
any of the smaller isky mega cams would work.like the old 270 mega cut on a 106 lsa. 270* 221 @ 50 .465 lift 106 or 108 lsa.it would have a nice chop to the idle and probably run decent as well.
 
Youtube Mopar 275DEH.....No speaka English :)

[ame="https://www.youtube.com/watch?v=siLvLAQF6Bg"]Dodge Dart 1970.mkv - YouTube[/ame]
 
Milling the heads down for a 1 point increase is OK. Going more may be possible. But this also introduces intake Fitment issues. At 8.0-1, a cam under 220 @ .050 will work fine with those gears.
 
I'm kind of in the same situation, and I'm a little confused about the part where it comes to shortening the valve guides...on the Hughes Engines website they say anything over .450 lift could have clearance issues, then on here on another thread someone mentioned that you're probably fine till .500. Any consensus on when the guides have to be cut down? I'd rather just drop in a cam...right now this thing just falls on its face past 4,500rpm. (71 Dart, 360/727/8.75, 2,300 stall).
 
There is no hard and fast rule on the valve guides. One may have interference at .450 lift. One may not have interference until .550. The factory tolerances were crummy, and that's givin um a compliment. My rule has always been to measure and expect to cut the guides regardless. It's not something you can lay a blanket rule over.
 
Is that because the rocker arm ratio is all over the place, or is it basically everything that's the problem?
 
No I thought we were discussing the valve guide height. They are all over the place, not just from engine to engine but also from guide to guide.
 
Gonna need a Holley (or Holley type) carburetor, and patience to tune it,
distributor modification to shorten up amount of advance travel, and
a torque converter loose enough to let it idle in gear. If you're gonna keep
the 3.23 gears, don't use more than approx 2500 stall and make sure
to use a trans cooler.
 
Thanks everyone for the help! Anyone have suggestions on milling the heads. I am goin to go this route since my buddy has machine shop and will cost zero. What can I safely remove from the heads and not interior milling intake? I did this while ago with a 360 using kb191's to get proper quench but can't remember how much I had them milled.. Thanks!
 
madmoparmick said:
Gonna need a Holley (or Holley type) carburetor, and patience to tune it
Click to expand...

Innnnnncorrect! All so very very wrong!

Any carb will need the time to be tuned and he doesn't "need" a Holley or Holley type carb. He needs the knowledge, skill and time to tune any carb that goes on top. Be it a Holley, Edelbrock, whatever aftermarket carb OR a OE carb.
 
JMO. I would not mill heads to increase compression. It takes a BIG cut to make an appreciable difference. Machine shops will charge extra for making big cuts, because they take several passes. That means more time. More money. Plus, factor in cutting the intake manifold. That will be a big cut, too. More money. It's not just the money issue, but now you will have a specific pair of heads and intake that can only be used with each other. There are better ways to go about, IMO. Of course, that's just my opinion. Take it for what it's worth.
 
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