what solid cam is equivalent to a hyd 268 ?

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stroker402

stroker402

1968 dart GTS convertible
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what solid cam are you all using that is equivalent to a hyd 268 cam ? I have a big erson solid 510 lift - 284 dur, 2000-7200 rpm range in it now , just does not have the bottom end torque and takes too long to whind up.
it is going into a non commando 273 . 4 speed, headers , ld340, 650 dp, electronic ign, low compression 4 relief pistons, stock closed chamber 920 heads and 3.55 gears.
everyone talks about the 268 cam here on fabo.
 
For what you are doing are you married to the solid? I'd consider a hydraulic.

If not, call Jim at Racer Brown and let him grind you a cam.
 
Bump the "050 duration " 10-12 degrees... " for a solid flat tappet ,compared to a hydraulic lifter cam.
Same rpm zone... the solid lifter WILL NEED BETTER VALVE SPRING, and a basic blueprint of the valvetrain.
Just what I know...
 
yellow rose said:
For what you are doing are you married to the solid? I'd consider a hydraulic.

If not, call Jim at Racer Brown and let him grind you a cam.
Click to expand...

I have two set of adjustable rockers and no hyd rocker assemblies. like to use what I have .
the big erson cam I'm currently running is just too much for street driving.
 
I would use a solid 260 deg cam if you want a balance between top and bottom rpm range in a 273 with low compression
 
teringer said:
I would use a solid 260 deg cam if you want a balance between top and bottom rpm range in a 273 with low compression
Click to expand...
I have done a compression reading Cold on the 273 with 160# on all cylinders . I have the thin .028 head gaskets also.
 
I would stick around the 260 /112lc/ .440 I/e for a solid, I ran a 275 deg/.424 112lc solid in my 318 and it was way to big
 
adjustable rockers can be used with hydraulic lifters, probably need different length pushrods. a good solid is 20-246-4, 270*/270*, 224*/224* at .050", .468"/.468" and 110* lobe seperation , Comp cams
 
Low compression 273? Isky E-4. Solid lifter cam. No other. You can't build torque and horsepower with much else.
 
stroker402 said:
I have done a compression reading Cold on the 273 with 160# on all cylinders . I have the thin .028 head gaskets also.
Click to expand...
Wow, you've got 160 cold, with that 284? That's pretty awesome. But it's also gonna be a bit of a problem to downcam.How is that 160 even possible? Did you machine the decks or the heads,or back way off on the lash?
With 8/1 Scr and an ICA of 70*, your pressure should be like 115 or less and yes, that would make a pitiful bottom end, and with 3.55s, that's a serious mismatch.
So in my head something does not compute about the 160psi number.
But if 160 is correct, then your Scr has to be up around 10.6 according to my calcs. And if that's true, then you might be in a pickle.
If the 160 is true and the 10.6 is true, then going to the .039 gasket this will drop your Scr to 10.0, and that allows down to a 62* ICA, for a pressure of 162ish.And this will up your low-rpm performance by about 54%.
>But if you lashed her loose, and that 70* ICA was more like 65,then you could get 160psi with a 10.1Scr,and it still does not compute to 8.0 Scr, so IDK...
>But if the 160 is out to lunch, and 115 is more accurate, then you have a ton of room for improvement.Too many tons.The E-4 is a 260-260-108Solid,and in at 108,might boost the pressure to 126(at zero lash) and increase your low-rpm performance 25%
> But lashed to drop 4*, the ICA would be 54*, and now the pressure would be 130@ 8/1,for a 30% Boost,EDIT; or 154 @9.0Scr for a 54% boost
So I don't know chit about 273s, so I guess this is better than a poke in the eye with a sharp stick; but I do know that 126/130psi is pretty poor.

So I guess if it was me, I'd find a second compression tester, warm it up,lash the valves, and retest the pressure at WOT, as many cycles as it takes to get two consecutive same pressure readings.
 
Last edited:
Abodybomber said:
Bump the "050 duration " 10-12 degrees... " for a solid flat tappet ,compared to a hydraulic lifter cam.
Same rpm zone... the solid lifter WILL NEED BETTER VALVE SPRING, and a basic blueprint of the valvetrain.
Just what I know...
Click to expand...

This ^^^^^^^ is absolutely spot on.
 
The Isky E4 in a 273 works very well. I've tried a few cams in 273s over the years and the E4 is the best I found for use in low and high compression 273s. It's similar to the factory hi-po cam. Gotta agree with toolmamikes recommendation.
 
AJ/FormS said:
Wow, you've got 160 cold, with that 284? That's pretty awesome. But it's also gonna be a bit of a problem to downcam.How is that even possible?
With 8/1 Scr and an ICA of 70*, your pressure should be like 115 or less and yes, that would make a pitiful bottom end, and with 3.55s, that's a serious mismatch.
So in my head something does not compute about the 160psi number.
Click to expand...
I found out that this 273 has the 340 thicker rods with floating wrist pins . maybe the 340 rod alittle longer ?
 
grimreaper said:
The Isky E4 in a 273 works very well. I've tried a few cams in 273s over the years and the E4 is the best I found for use in low and high compression 273s. It's similar to the factory hi-po cam. Gotta agree with toolmamikes recommendation.
Click to expand...
what are the specs on the isky e-4 cam ?
 
stroker402 said:
I'm not quite understanding what you mean by this >Bump the "050 duration " 10-12 degrees... " for a solid flat tappet ,compared to a hydraulic lifter cam.explain please .
Click to expand...

In order to find a solid lifter camshaft that is "about the same" as a known hydraulic, you need to add around 10 degrees duration. In other words, a 278-280 solid will be "about the same size" as a comparable 268 hydraulic.
 
AJ/FormS said:
Wow, you've got 160 cold, with that 284? That's pretty awesome. But it's also gonna be a bit of a problem to downcam.How is that 160 even possible? Did you machine the decks or the heads,or back way off on the lash?
With 8/1 Scr and an ICA of 70*, your pressure should be like 115 or less and yes, that would make a pitiful bottom end, and with 3.55s, that's a serious mismatch.
So in my head something does not compute about the 160psi number.
But if 160 is correct, then your Scr has to be up around 10.6 according to my calcs. And if that's true, then you might be in a pickle.
Click to expand...
Yeah I know it was high I couldn't figure that out either. with the 4 relief pistons should be lower. This 273 engine was raced at one time 25 years ago . then it was parked. It is a fresh motor with no wear in the top rim of cyl bore . it was bored .030 over.
 
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