cam selection

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7dart0

7dart0

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70 dart 360 about 8.5 to 1,stock heads, 750 carb, A904 with stock converter, right now has stock 2;76 7 1/4 but going to 8 3/4 4;10 later in the summer. im looking for a good street cam with the occasional trip down the quarter mile. maybe something that has lope to it.
 
I think you'll get a lot of benefit from some head work and larger valves with a bigger cam. You're right on the edge of what most probably consider minimum compression but if I were going to do the cam, I'd do the heads, and in turn I'd at least do thinner headgaskets to get closer to 9.0 compression, might as well! I think you could do something like a Comp XE274 with nice results. I run the XE268 in my 318 with similar specs.
 
The .484/284 MP cam is too big, go just under that....
 
7dart0 said:
70 dart 360 about 8.5 to 1,stock heads, 750 carb, A904 with stock converter, right now has stock 2;76 7 1/4 but going to 8 3/4 4;10 later in the summer. im looking for a good street cam with the occasional trip down the quarter mile. maybe something that has lope to it.
Click to expand...


I've been where you are with several cars I did for other people years back. A big cam with two series gears = weak! The stock cam with 4.10's = almost as weak! :)

The gear swap late in the summer is the biggest concern for me? How much time are you planning to put on it thru the Spring and Summer?

If you haven't done it before, the difference in those gears is huge.....especially with a "stockish" converter. I'd actually want to pick two cams for both scenarios, but as a compromise, the XE268 that "mirage" spoke of is a decent choice to bridge the gap. I'd also consider the 275DEH grind...
http://www.compcams.com/Company/CC/cam-specs/Details.aspx?csid=636&sb=0
 
XE268 is a great all around cam, 284/484 worked great with my 3.91 rear. If you are going 4.10 you could go bigger. 3.73 gears would be my favorite driver gears. 3.91 is a little buzzy especially with 14 tires, and 3.55's feel like the car is more at home on the hiway. 3.73 is a good compromise.
 
I'm hoping to drive the car at least everyday. i do keep going back to that XE268 cam. i could drop to 3;73 gears im not to set on 4;10's.
 
I like Lunati's 268 VooDoo better.
 
If you plan on keeping the stock converter, your cam is a little bit for it. Ether swap out the converter or install Rhoads lifters.
IMO, milling the heads would be good. I don't know how much effort you want to put into the heads, but the above talk about it is spot on. Mill, bowl work with 2.02's wil add nice power all around.
 
7dart0 said:
70 dart 360 about 8.5 to 1,stock heads, 750 carb, A904 with stock converter, right now has stock 2;76 7 1/4 but going to 8 3/4 4;10 later in the summer. im looking for a good street cam with the occasional trip down the quarter mile. maybe something that has lope to it.
Click to expand...

Compu-Cams XE-262-H
Lift...................... .462"/.470"
Duration .............. 262*/270*
Duration @ .050" .. 218*/224*
Lobe Separation ... 110*
Centerline ........... 106*
Overlap ............... 46*

Good idle with a little 'rump-rump', and very good
low-end response.

Designed for 1300 to 5600 RPM's.

A very good 'bump-stick' for a 360 with Low-Compression {8.5-1},
an A-904 and a 'stock' Converter, and with 'Highway' 2.76 Gears.

'1970 Dart' ~ Shipping Weight.... #3180 lbs.

More response with > 3.55 ~ 3.70 ~ 3.91 Gears

Note: That XE-268-H 'needs' more Compression to gain optimal performance.
 
Maybe you could run the cam a few degrees advanced set it at 102 ic to help with the 2 series gears and stock converter for now.
 
how much milling of the heads can you get away with before you get into intake alignment problem and pushrod problems. i want to keep it simple with non adjustable rockers with hydraulic lifters. how much does milling bump up compression?
 
7dart0 said:
how much milling of the heads can you get away with before you get into intake alignment problem and pushrod problems. i want to keep it simple with non adjustable rockers with hydraulic lifters. how much does milling bump up compression?
Click to expand...

If you have the 360 'Open Chamber' combustion chamber Cylinder Heads
from 1970 thru 1974;

Casting Numbers
#3418915
#3671587

For every .0048" Milled, it will reduce the CC's by {1.0}.

You can 'safely' mill the Cylinder Head surface {.024"},
which will reduce CC's by {5.0}.

That will increase the Compression Ratio by {+.6}

And there will be no significant issues with the Intake Bolt
alignment, or Valve Train geometry problems.
 
good info to know. the heads i have are off of an old 87 dodge ramcharger. im at work so i dont know the serial numbers off hand
 
That answer isn't exactly black and white. (Almost) Here's why.

The factory lifter has approx. .080'of useful Range. The missing .020 is divided up into a non-useful area of .010 on top and .010 on the bottom. Head gasket comes into play now that the stock one is used up. The stock steel head gasket is listed @ approx. (IIRC) .028 thick.

If you mill .060 off the head and use a .042 gasket, you only lost .018 and the thicker gasket is to blame. No new gasket is required like this.

Make sure you can find the factory thin gasket or the head must be killed more to compensate for the thicker gasket.

The MoPar engines book states;

To reduce the chamber volume, remove .0048 from the head surface per 1cc of chamber volume. For each .010 removed from the head. ,0095 must be removed from the intake face of the head.

If all this work is done and you use a thicker head gasket, fitment will possible occur. Think before you leap. Find a on line compression ratio calculator. A 9.5-1 is the max I would go with what you have in mind. That's only 1 point of compression higher that what you say you have now. But you need to measure it to be absolutely sure. I highly advise this before milling.
 
Sorry for the double info post. I started this post almost an hour ago & all was fine until the local idiot (brother) called.
 
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