Erson Cam >> good with lots of compression ?

-
what I'm gathering mike is they used the racer brown cam st-12 with these specs in the d dart 273>..................
quote from a guy >>>>>>> I ran the ST-12 294/294 advertised and .485/.485 lift in a 1971 340 Challenger and it was a rocket. With 3.55 gears and G60-15 tires, it wouldn't even think about hooking up if I launched it over 1000 rpm.
mopar article says they ran the st -12 cam and milled the head .0065 off to raise the compression even more that stock 10.5 . Am I reading right mike ?
if that is the case, there would be plenty of pv clearance with stock 10.5 pistons .
 
stroker402 said:
what I'm gathering mike is they used the racer brown cam st-12 with these specs in the d dart 273>..................
quote from a guy >>>>>>> I ran the ST-12 294/294 advertised and .485/.485 lift in a 1971 340 Challenger and it was a rocket. With 3.55 gears and G60-15 tires, it wouldn't even think about hooking up if I launched it over 1000 rpm.
mopar article says they ran the st -12 cam and milled the head .0065 off to raise the compression even more that stock 10.5 . Am I reading right mike ?
if that is the case, there would be plenty of pv clearance with stock 10.5 pistons .
Click to expand...
I read the same but check the clearance just in case.
 
.oo65 is not going to make much difference especially if the gasket was changed from stock
now .030...is not much more than .010 + a stock shim gasket when you put in a .040+ gasket
as the two cams are not the same as toolman says - you have to check
the racer brown is going to have quicker acceleration than the most likely chevy/ .842 based erson- so even if it was shorter it would get the valve openfurther around the piston / valve contact point around TDC
 
Wyrmrider said:
.oo65 is not going to make much difference especially if the gasket was changed from stock
now .030...is not much more than .010 + a stock shim gasket when you put in a .040+ gasket
as the two cams are not the same as toolman says - you have to check
the racer brown is going to have quicker acceleration than the most likely chevy/ .842 based erson- so even if it was shorter it would get the valve openfurther around the piston / valve contact point around TDC
Click to expand...
yes .... .0065 is probaly the thickness of paper. I for get the oem thickness of the steel shim gasket on commando... maybe .022 ...........don't know .
 
maybe the .0065 was a typo- but then it's close to a "minimum cut"
sometimes have to go more than minimum to equalize cc's end to end
 
found this mopar dude on FB stating quote :
Jared Carlston Everyone seems to forget that most 273's came with heads that are nearly identical to those....and shim head gaskets. I've got a set of those pistons under 920 heads with a massive cam... .515" of lift and 284* of duration on a 108 centerline and there's plenty of room due to the valve reliefs. In the area of .100-.120" if I recall correctly with over torqued permatorques. I think you'll be fine but check it if you can.
 
stroker402 said:
found this mopar dude on FB stating quote :
Jared Carlston Everyone seems to forget that most 273's came with heads that are nearly identical to those....and shim head gaskets. I've got a set of those pistons under 920 heads with a massive cam... .515" of lift and 284* of duration on a 108 centerline and there's plenty of room due to the valve reliefs. In the area of .100-.120" if I recall correctly with over torqued permatorques. I think you'll be fine but check it if you can.
Click to expand...
Good to hear that but he measured. So did I with my mild cam. You can pull the trigger and not measure if you wish. Good luck.
 
Always check. I put a combo together I had run before. Pistons, heads, cam all the same, No milling. Cam I was running was 260 at .050 and .616 lift. On start up it bent 6 intake valves. I couldn't believe it. I tore it down and the valves were hitting the pistons of course. So I measured lift it read .640 so I pulled the cam and checked the numbers and they were right numbers for that .616 cam. So I measured the cam. It was 272 at .050 .640 lift. Cam was stamped with the wrong number. Never trust numbers always measure.
 
I purchased a pair of oem head gaskets for the 1968 318 {#2806 984}, {.020" thickness} which are designed for the 3.91" Bore.
When I measured the bore it's pretty close to that number , 3.99 ..... the thickness of gasket is quite thicker. more like .050 on the rings ........ I read somewhere that you can't have the gasket ring come close to the cyl bore , it has to be some distance away.
I'm assuming that .020 number is when compressed? This is the last pair of oem mopar gaskets out there . I searched high and low for some small bore gaskets........... last oem pair I could find .
 
I asked if fbo had oem shim 273 head gaskets 3.65 bore and said quote "Yes, of course. We need the finished bore size and thickness you require.
They are available in .027 to .140 thickness in about .005 increments.
Starting at $69.00 each plus shipping."
Thank You

Don & Dana


FBO Ignition Systems Since 1982

541-942-5920 www.4secondsflat.com

FBO Ignition Modules & Custom Components-Pertronix Ignition Products-Daytona Sensors Engine Management-Distributor Recurves-Repairs-Rebuilding- Modifications
 
I think I will get around to building this 273 beast this year 2021. Soon !
my 273 has stock bore with a ball hone . I think I'll use the thinnest shim gasket of .027 with the stock dome pistons . I thought the stock/ oem mopar shim gaskets were .022 .
 
You must log in or register to reply here.
-

Back
Top