pishta
I know I'm right....
what 'long tube headers' do you plan to run?
they are "custom made" by a friend of mine which is running a Hot Rod-shop here in Germany.what 'long tube headers' do you plan to run?
again i´m into throwing a 273 together (as my wife complained that the fish was to rude and not really driveable in normal traffic with the beefed up Magnum motor)
Honestly, you should teach your wife how to drive, instead of band aiding the situation. It will serve her well in the future, and you'll not have to remove the Magnum. But it sounds like you've made your mind up, so read on.
so decision were made the Magnum has to go and i will stick it into my Dodge D100 Truck next year.
so here are my plans i wanted to hear your opinions on that
this is given and it should stay as it is (money wise)
273 .040over
318 Heads with compcams Springs 901-16, bowl blended, opened intake runners to 340size, bit of portwork, polished chamber and polished exhaust runners.
Don't even worry about the port work. For all the work involved, it's not going to net much. This isn't a race motor. You've said your "tuning down" from a Magnum engine. No need to "tune up" the 273, because it's such a small displacement, you'll not see porting benefits until past 5K RPM, IMO.
Stock converter, 904er with shift kit, 3,91 rear with 26inch tall tires
600 cfm Holley with Vac.Sec.
longetube headers unrestricted mufflers 2,5inch dual exhaust
oil pan - windage tray:
standard oil pan + windage tray
deep 8quart pan without windage tray
or deep 8quart pan + windage tray
No need for all the hoorah with the oil pan. You're not building a race engine, so the stock oiling system, including the pan is perfect!
camshaft - 340 HPstock cam: should i go 4 degrees advanced or not ? think it could/would give me a bit more fun on the low end
4*- 6* would be a good "guess". That's a sizable cam for a 273 on the street, so any bottom end torque you can come up with will help. I would CERTAINLY advance it, though.
intake: i do have an 360° offenhauser single plane and i also have a stock 340 4bbl-iron beast i would tend to use the offy, as it was on the motor when i bought the Barracuda years ago, but the runners are 318 size, which will be fine for the small motor (but the heads are allready opened up to match 340 gaskets, will it hurt too much using smaller intake on wider heads ? Guess the otherway around would create more turbolences ??)
The Offenhauser piece is a good one. Since you have it, use it.
thanks
Good response RRR.
Another option would be, though "illegal", to tame the 360 and disguise it as 273. Or does TÜV actually check block numbers?
Edit: with TÜV being our DMV, sorta...
Talking about solid lifter cams
Here is why I said that ; The solids have faster rate clearance ramps. This allows you to install one size bigger cam, without the cylinder pressure loss, usually associated with that amount of.050 duration
Another way to look at it is;with the same advertised,you can have the next larger sized .050
Here is an example, purely hypothetical;
a 262/268/110 cam, might have, as a FTH ,216/[email protected]. But same cam as a solid, might have 224/229.. That's a difference of 8/7, and one cam size is generally considered to be 7*
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Now from the other side, if you wanted a 216/222 cam, a FTH might be 262/268. But the solid might be 255/261, again 1 size difference.
To get a sense of that 262 vs 255, let's install these two, in the same 273 with no other changes, again at split-overlap, and lets make them 110LSAs. And I'm just gonna capture the important numbers from the Wallace Calculator, as; Scr/Dcr/Psi/VP.
>So with the FTH, I get;
8.0/6.62/125/82 This would be very weak.But with more Scr, I get
9.6/7.90/157/104 And still more
9.9/8.14/163/108 Here the pressure is maxed out for 95Ron, and you might have to run 98 for WOT work. So this is as good as it gets with a FTH.
> Next ,the solid; I get;
8.0/6.79/129/88 Again , weak, but better than with the FTH
9.6/8.11/163/111 About as good as it gets
9.9/8.36/169/115 Too much pressure now,for available fuel!
So now look at the Scrs, where the pressure is maxed out at 163psi. Notice the numbers are 9.9 for the FTH and 9.6 for the Solid.
If your 273 came in at 9.6Scr, and you installed the FTH, you would be sacrificing 6psi and more importantly 111/104= a loss of 6.7% in VP, and that's a heavy loss for a 273.
But if your Scr came in at 9.9 you couldn't even run an
equivalent-at-.050 solid, because the pressure would be too high.
Yep!All this dynamic compression stuff is giving me a headache. LOL. The Comp 270S is lopey but very tame in a low compression 318 I am running in my short-box A-833 O/D truck these days. 224*@.050", 110LSA, .468" lift. I run the lash at .018/.022" hot but you could open it up to .028/.032" if it was too rough idling in a 273. That E-4 Isky would be a sure-fire stable idle with some authority, but not very choppy. A friend has one in a similar 318 to mine and it's stocker-smooth when warm, idling.
How about a Isky E-4? My 273 had 9.68 static compression and the E-4 specs are as follows. .425 lift 260/260° 216/216° @.050. 108° lobe center.
That's all the Wallace Calculator needs. Sock-it-to-me. All I do is punch the numbers in, and try to interpret the results.Yepp, it causes headache ... but i think i got thepoint behind it... Unfortunately it's very complex to do those calculations and AJ/FormS deserves my greatest respect.
Thanks foor showing me that the 340 cam wouldn't fit.
Maybe i will simply take the 318 stock cam but it would also be interested to know the results for the SSI11309 cam. But calculation will not work as i only have duration LSA and lift.
Yes, I did advance it a couple degrees. I usually run 92 octane non alcohol Premium with no issues. I have ran 87 but I didn't hot rod it. The shop that did the heads polished the chambers which may help. Those closed chamber 273 heads are pretty efficient with a little work. Thanks for the update.In at split overlap(44*), for an ICA of 58*
Static compression ratio of 9.68:1.
Your dynamic compression ratio is 8.07:1 .
Your dynamic cranking pressure is 161.70 PSI.
V/P (Volume to Pressure Index) is 108...................... 108 ..
On the money Mike
In 4* advanced at 104*,for a ICA of 54*
Static compression ratio of 9.68:1.
Your dynamic compression ratio is 8.28:1 .
Your dynamic cranking pressure is 167.18 PSI.
V/P (Volume to Pressure Index) is 115...................... 115 ..
Probably too much for pump gas
Well it's a 367 with KB107s. It's been decked to get 10.9Scr and .005 pop-up for .034 Q with .039gaskets.She's got a Milodon 7qt roadrace pan with their tray and pick-up, that I run just 5 qts in.Sorry to hi-jack this post but...what are the current specs on your car and engine A J?
All this dynamic compression stuff is giving me a headache. LOL. The Comp 270S is lopey but very tame in a low compression 318 I am running in my short-box A-833 O/D truck these days. 224*@.050", 110LSA, .468" lift. I run the lash at .018/.022" hot but you could open it up to .028/.032" if it was too rough idling in a 273. That E-4 Isky would be a sure-fire stable idle with some authority, but not very choppy. A friend has one in a similar 318 to mine and it's stocker-smooth when warm, idling.
That's all the Wallace Calculator needs. Sock-it-to-me. All I do is punch the numbers in, and try to interpret the results.
going in. Pending tc and gear choice( I'm running 323) you could be disappointed.All this dynamic compression stuff is giving me a headache. LOL. The Comp 270S is lopey but very tame in a low compression 318 I am running in my short-box A-833 O/D truck these days. 224*@.050", 110LSA, .468" lift. I run the lash at .018/.022" hot but you could open it up to .028/.032" if it was too rough idling in a 273. That E-4 Isky would be a sure-fire stable idle with some authority, but not very choppy. A friend has one in a similar 318 to mine and it's stocker-smooth when warm, idling.